Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infue...Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder.展开更多
The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds industry.The appearance of the LPBF mak...The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds industry.The appearance of the LPBF makes it possible to design and produce complex conformal cooling channel systems in molds.Thus,LPBF-processed tool steels have attracted more and more attention.The complex thermal history in the LPBF process makes the microstructural characteristics and properties different from those of conventional manufactured tool steels.This paper provides an overview of LPBF-processed tool steels by describing the physical phenomena,the microstructural characteristics,and the mechanical/thermal properties,including tensile properties,wear resistance,and thermal properties.The microstructural characteristics are presented through a multiscale perspective,ranging from densification,meso-structure,microstructure,substructure in grains,to nanoprecipitates.Finally,a summary of tool steels and their challenges and outlooks are introduced.展开更多
Inflammatory breast cancer(IBC)is a rare disease in clinic,with rapid progression and poor prognosis.It is easy to be misdiagnosed in cases of atypical clinical symptoms and imaging findings.Combined with the medical ...Inflammatory breast cancer(IBC)is a rare disease in clinic,with rapid progression and poor prognosis.It is easy to be misdiagnosed in cases of atypical clinical symptoms and imaging findings.Combined with the medical record of IBC in our hospital,the author explores the causes of misdiagnosis of inflammatory breast cancer,based on clinical manifestations,diagnosis,imaging examination,treatment and so on,so as to improve the clinical physicians understanding and diagnosis of this disease.展开更多
Breast cancer is one of the most frequent malignant tumors and is receiving more attention due to the increasing incidence and detection rate.Further studies regarding prognosis genes for biology are being conducted.T...Breast cancer is one of the most frequent malignant tumors and is receiving more attention due to the increasing incidence and detection rate.Further studies regarding prognosis genes for biology are being conducted.The paper aims to review the prognostic indexes of breast cancer such as p16,Her-2,Ki-67,MCM7.展开更多
Magnesium(Mg)alloys,as the lightest metal structural material with good damping capacities,have im-portant application prospects in realizing structural lightweight and vibration reduction.However,their engineering ap...Magnesium(Mg)alloys,as the lightest metal structural material with good damping capacities,have im-portant application prospects in realizing structural lightweight and vibration reduction.However,their engineering application is greatly limited by poor plastic formability.Wire and arc additive manufactur-ing(WAAM)provides a potential approach for fabricating large-scale Mg alloy components with high manufacturing flexibility.In this study,the evolution of the solidification microstructure of a WAAM-processed Mg-Al-based alloy was quantitatively analyzed based on the analytical models;then,the cor-relations between the solidification microstructure and mechanical properties/damping capacities were investigated.The results revealed that the WAAM-processed Mg-Al-based alloy with an equiaxed-grain-dominated microstructure displayed a simultaneous enhancement in mechanical properties and damping capacities compared to those of the cast Mg-Al-based alloy.The good combination of mechanical prop-erties and damping capacities are mainly attributed to the weakened basal texture with a relatively high Schmid factor for basalslip,the twinning-induced plasticity(TWIP)effect associated with the profuse{10-12}tensile twinning,and the relatively high dislocation density caused by the thermal stress during the WAAM process.展开更多
Objective To investigate the molecular classification of endometrial cancer(EC)and atypical endometrial hyperplasia(AEH)patients treated with fertility-sparing treatment(FST),and its relationship with clinicopathologi...Objective To investigate the molecular classification of endometrial cancer(EC)and atypical endometrial hyperplasia(AEH)patients treated with fertility-sparing treatment(FST),and its relationship with clinicopathological factors and treatment efficacy.Methods:A total of 52EC and AEH patients who received FST and molecular classification tested by next generation sequencing in Peking University People's Hospital from June 2020 to December 2022,were retrospectively collected.We analyzed the relationship between molecular classification and clinicopathological factors and treatment outcomes.Results(1)Of the 52 patients,including 46EC and 6 AEH patients,42(80.8%)achieved complete remission(CR)after FST,with a median time to achieve CR of 9 months.Ten cases(23.8%)had recurrence.(2)Patients were distributed into 4 molecular subgroups as 39 cases(75%)of copy number low(CNL),7 cases(13.5%)of microsatellite instability-high(MSI-H),4 cases(7.7%)of POLE mutations(POLEmut),and 2 cases(3.8%)of copy number high(CNH).Patients with MSI-H subgroup had more family history of tumor(6/7),more with loss of expression of mismatch repair(MMR)protein(7/7),and higher expression level of Ki-67(3/3).(3)Patients with MSI-H subgroup had the lowest CR rate at 6 months(0/7,P=0.014),and survival analysis showed that such patients were less likely to achieve CR than those with CNL(P=0.022).For CNL patients,median 6-month CR rate was 40.6%.In addition,CR was obtained in 3(3/4)POLEmut patients and 2(2/2)CNH patients,respectively.Conclusions Molecular classification relates with the treatment response in patients with EC and AEH receiving FST.Patients with MSI-H subgroup have poor treatment efficacy,and patients with CNL need to be further divided to predict treatment benefit.There are also a few successful cases in POLEmut and CNH subtgroups,which needs further research.展开更多
Quasicrystal(QC)-reinforced metal matrix composites fabricated by rapid solidification present promising new opportunities to develop high-strength alloys with multiple functions.In this research,specially designed Al...Quasicrystal(QC)-reinforced metal matrix composites fabricated by rapid solidification present promising new opportunities to develop high-strength alloys with multiple functions.In this research,specially designed Al–Fe–Cr samples possessing an Al–Fe–Cr quasicrystal-reinforced Al matrix structure were manufactured using a laser powder bed fusion(LPBF)process.Based on the optimized process parameters of laser scanning speed and hatch distance,an almost dense(99.8%)free-crack sample was obtained with the multiscaled heterogenous structure induced by the nonuniform rapid solidification in a single molten pool.The results show that nanosized Al–Fe–Cr quasicrystalline particles of different sizes are heterogeneously distributed in theα-Al columnar grain structure.In detail,the coarseflower-like and spherical QC particles can be observed at the molten pool boundary,and thefine spherical Al–Fe–Cr QC is located inside the laser fusion zone.The orientation relationship between the Al matrix and the icosahedral Al–Fe–Cr QC is as follows:Al[112]||i5 with a semicoherency feature.The novel designed LPBF-processed Al–Fe–Cr alloy exhibits high mechanical strength due to the ultrafine multireinforced microstructure-induced Orowan strengthening effect.For instance,the ultimate tensile strength,yield strength and elongation of the sample processed with LPBF are 530.803.19 MPa,395.066.44 MPa,and 4.16%0.38%,respectively.The fractographic analysis shows that the fracture mechanism presents a combination of ductile‒brittle fracture.展开更多
Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum alloy.The influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties w...Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum alloy.The influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties were investigated.The results indicated that as the electric arc TS increased,the size and the volume fraction of equiaxed grain decreased.The high arc TS during WAAM also promoted the precipitation of theθ(Al2Cu)phase.The volume fractions ofθ’’andθ’phases reached maximum values when TS is 350 and 250 mm/min,respectively.The thermal cycle facilitated the precipitation of theθ’phase.In addition,the micro-hardness and tensile strength of the alloy were analyzed,and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength(273.5 MPa)and yield strength(182.9 MPa)compared to those fabricated at 250 mm/min.展开更多
The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is underutili...The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is underutilized.In this work,compared with the normal T6 heat treatment,a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary AlZr.It was found that a heterogeneous grain structure,which consisted of ultrafine equiaxed(~0.82μm)and columnar(~1.80μm)grains at the bottom and top of molten pool,respectively,was formed in the SLM processed sample.After direct aging(DA),the ultrafine grains were maintained and a mass of spherical coherent L1-AlZr particles with a mean radius of approximately1.15 nm was precipitated.In contrast,after solution treatment and aging(STA),a significant grain coarsening occurred in the equiaxed grain region.Meanwhile,the coarsening L1-AlZr particles,nano-sized S phases and GPB zones were detected in the STA sample.This subsequently induced that the yield strength of the DA sample(~435 MPa)was higher than that of the STA sample(~402 MPa)owing to the grain boundary strengthening and precipitation strengthening.Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6 alloy(~393 MPa).Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6alloy(~393 MPa).展开更多
The control of grain morphology is important in laser additive manufacturing(LAM),as grain morphology further affects the hot cracking resistance,anisotropy,and strength–ductility synergy of materials.To develop a so...The control of grain morphology is important in laser additive manufacturing(LAM),as grain morphology further affects the hot cracking resistance,anisotropy,and strength–ductility synergy of materials.To develop a solidification-control solution and achieve columnar-to-equiaxed transition(CET)in Al-based alloys during LAM,Sc-and-Zr-modified Al-Mg alloys were processed via directed energy deposition(DED).CET was achieved by introducing high potent primary Al_(3)(Sc,Zr)nucleation sites ahead of the solidification interface.Furthermore,the relationship between the solidification control parameters and precipitation behavior of primary Al_(3)(Sc,Zr)nucleation sites was established using the time-dependent nucleation theory.Then,the CET was studied according to the Hunt criterion.The results indicated that coarse columnar grain structure was still obtained at the inner region of the molten pool at low Sc/Zr contents owing to the effective suppression of the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites via rapid solidification during DED.In addition,the relatively low melt temperature at the fusion boundary unavoidably promoted the precipitation of primary Al_(3)(Sc,Zr)nucleation sites,which resulted in a fine equiaxed grains band at the edge of the molten pool.As the Sc/Zr content increased,the solidification cooling rate was not sufficient to suppress the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites,and a fully equiaxed grain structure was obtained.Furthermore,the effect of the layer-by-layer manufacturing process on the subsequent precipitation strengthening of secondary Al_(3)(Sc,Zr)precipitates was discussed.Both the remelting and subsequent aging during thermal cycling should be considered to achieve greater precipitation strengthening.展开更多
Laser powder bed fusion(L-PBF)of Sc/Zr-modified Al-based alloys has recently become a promising method for developing a new generation of high-performance Al alloys.To clarify the modification roles of Sc/Zr elements,...Laser powder bed fusion(L-PBF)of Sc/Zr-modified Al-based alloys has recently become a promising method for developing a new generation of high-performance Al alloys.To clarify the modification roles of Sc/Zr elements,an Al–4.66Mg–0.48Mn–0.72Sc–0.33Zr(wt.%)alloy was processed using L-PBF.The effect of the local solidification condition of the molten pool on the precipitation behavior of primary Al_(3)(Sc,Zr)was analyzed based on time-dependent nucleation theory.It was found that primary Al_(3)(Sc,Zr)inevitably precipitated at the fusion boundary,while its precipitation could be effectively suppressed in the inner region of the molten pool.This subsequently induced the formation of a heterogeneousα-Al matrix.After direct aging,the heredity of solidification microstructure introduced heterogeneous secondary Al_(3)(Sc,Zr)precipitates withinα-Al matrix.Owing to the inverse relationship between grain boundary strengthening and precipitation strengthening,the direct-aged sample with dual heterogeneous structures exhibited reduced mechanical heterogeneity,resulting in lowered hetero-deformation-induced hardening.The low strain-hardening capability in the direct-aged sample promoted necking instability while inducing a large Lüders elongation,which effectively improved the tensile ductility.展开更多
Hybrid manufacturing(HM)uses additive manufacturing(AM)techniques to prepare complex or fine structures on traditional processing parts,which can fully utilize the advantages of AM to form complex parts,and the high e...Hybrid manufacturing(HM)uses additive manufacturing(AM)techniques to prepare complex or fine structures on traditional processing parts,which can fully utilize the advantages of AM to form complex parts,and the high efficiency and low cost of conventional processing methods in manufacturing regular components.A bimetal material was produced by selective laser melting(SLM)of AlSi10Mg on the deformed Al6061 alloy substrate in this study.Firstly,the interface characteristics of the two alloys were studied.The results show that a metallurgical interface with a thickness of 100–200μm was formed as the result of the Marangoni convection during SLM preparation.In detail,the circular flow in the melt pool at the interface led to the dilution of alloying elements and the change of microstructure.Moreover,a suitable first-layer thickness can eff ectively suppress the hot cracks at the interfacial region.Based on the optimized results,the hybrid manufactured samples with diff erent SLM processed volume ratios(SLM-part)to the substrate were prepared to study the mechanical properties and the deformation behavior of hybrid parts.The results show that the volume ratio of the SLM-part to the substrate had an influence on the strength and the elasto-plastic behavior by aff ecting the distribution of plastic deformation.展开更多
In the context of popularized healthcare,cloud computing centers are used to collect medical data from the cloud and diagnose illnesses.This means a technical framework that can be applied to the medical diagnostic pr...In the context of popularized healthcare,cloud computing centers are used to collect medical data from the cloud and diagnose illnesses.This means a technical framework that can be applied to the medical diagnostic process in popularized healthcare is needed in order to provide technical support.Based on the evidence fusion theory,this study established a multi-modality image evidence fusion method,which can simulate the doctor’s diagnostic process and use multiple modalities of medical images to diagnose illnesses.This study used the evidence fusion method to fuse two different modalities of medical images.The accuracy of the diagnosis after fusion was higher than that of diagnosis through two modalities separately.This fusion method has achieved great results in the process of multi-modality image fusion.展开更多
Laser powder bed fusion(L-PBF)-processed high-silicon steel has great advantages in freely designed electric engines,and various studies have been conducted in this field.However,the analysis of both the mechanical an...Laser powder bed fusion(L-PBF)-processed high-silicon steel has great advantages in freely designed electric engines,and various studies have been conducted in this field.However,the analysis of both the mechanical and magnetic properties,focusing on the multiscale microstructure under as-fabricated and heat-treated conditions,which is indispensable for industrial applications,has not been performed.In this study,an Fe–Ni–Si sample was fabricated using the L-PBF process.Subsequently,the following hot isotropic pressing(HIPing)process was employed as a post heat treatment step for the Fe–Ni–Si alloys.The effects of HIPing on the microstructure were investigated,focusing on the metastable stable phase transformation in the Fe–Ni–Si system.X-ray diffraction results showed single-phase fccγ(Fe,Ni)in the L-PBF-processed samples before and after HIPing.Moreover,the acicular Ni/Si-rich structure(formed in the as-fabricated L-PBF sample because of its high cooling rates)transformed to the equilibrium austenite,Ni3Si,and FeNi3 phases during HIPing.After HIP,the compressive modulus and strength increased from 11 GPa and 650 MPa to approximately 18 GPa and 900 MPa,respectively.The magnetic properties were evaluated via a hysteresis loop,and the coercivity increased from 1.8 kA/m and to 2.9 kA/m after the HIPing process.展开更多
In this study,the effect of triple-cycling heat treatment on the microstructure,phase,and compression behaviour of directed energy deposited(DED)Ti-7Mo alloy was investigated with a focus on a non-equilibrium to equil...In this study,the effect of triple-cycling heat treatment on the microstructure,phase,and compression behaviour of directed energy deposited(DED)Ti-7Mo alloy was investigated with a focus on a non-equilibrium to equilibrium microstructure transition.As a result of thermal accumulation,in situ cycling,and rapid solidification,the as-deposited sample presents a continuous gradient microstructure withα-Ti in the top region andα+βin the bottom region.After the triple-cycling heat treatment,theα+βTi at the bottom region,which is non-equilibrium,changes to a state of equilibrium nearα-Ti.Meanwhile,the microstructure becomes more uniform throughout the entire sample.The morphology of theα-Ti phase changes from acicular to a short rode-like shape with increases in the number of dimensions.In terms of the mechanical properties,both the microhardness and compression properties were improved,particularly with respect to the fracture characteristics.The heat-treated sample possesses a much higher ductility than the brittle fractural behaviour.This work provides new insights into the microstructure and property optimisation and homogenisation of DED-processed Ti-based components with cycling heat treatment.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFB4600300)the National Natural Science Foundation of China(No.U22A20189,52175364)the China Scholarship Council(Grant No.202206290134)。
文摘Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder.
基金financial supports provided by the China Scholarship Council(Nos.202206 290061 and 202206290062)。
文摘The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds industry.The appearance of the LPBF makes it possible to design and produce complex conformal cooling channel systems in molds.Thus,LPBF-processed tool steels have attracted more and more attention.The complex thermal history in the LPBF process makes the microstructural characteristics and properties different from those of conventional manufactured tool steels.This paper provides an overview of LPBF-processed tool steels by describing the physical phenomena,the microstructural characteristics,and the mechanical/thermal properties,including tensile properties,wear resistance,and thermal properties.The microstructural characteristics are presented through a multiscale perspective,ranging from densification,meso-structure,microstructure,substructure in grains,to nanoprecipitates.Finally,a summary of tool steels and their challenges and outlooks are introduced.
文摘Inflammatory breast cancer(IBC)is a rare disease in clinic,with rapid progression and poor prognosis.It is easy to be misdiagnosed in cases of atypical clinical symptoms and imaging findings.Combined with the medical record of IBC in our hospital,the author explores the causes of misdiagnosis of inflammatory breast cancer,based on clinical manifestations,diagnosis,imaging examination,treatment and so on,so as to improve the clinical physicians understanding and diagnosis of this disease.
文摘Breast cancer is one of the most frequent malignant tumors and is receiving more attention due to the increasing incidence and detection rate.Further studies regarding prognosis genes for biology are being conducted.The paper aims to review the prognostic indexes of breast cancer such as p16,Her-2,Ki-67,MCM7.
基金supported by the National Key Research and Development Program of China (No.2021YFB3701100)the National Natural Science Foundation of China (Nos.U20A20234,51874062)+1 种基金the Postdoctoral Science Foundation of China (No.2022M710503)the Chongqing Foundation and Advanced Research Project (No.cstc2019jcyj-zdxmX0010).
文摘Magnesium(Mg)alloys,as the lightest metal structural material with good damping capacities,have im-portant application prospects in realizing structural lightweight and vibration reduction.However,their engineering application is greatly limited by poor plastic formability.Wire and arc additive manufactur-ing(WAAM)provides a potential approach for fabricating large-scale Mg alloy components with high manufacturing flexibility.In this study,the evolution of the solidification microstructure of a WAAM-processed Mg-Al-based alloy was quantitatively analyzed based on the analytical models;then,the cor-relations between the solidification microstructure and mechanical properties/damping capacities were investigated.The results revealed that the WAAM-processed Mg-Al-based alloy with an equiaxed-grain-dominated microstructure displayed a simultaneous enhancement in mechanical properties and damping capacities compared to those of the cast Mg-Al-based alloy.The good combination of mechanical prop-erties and damping capacities are mainly attributed to the weakened basal texture with a relatively high Schmid factor for basalslip,the twinning-induced plasticity(TWIP)effect associated with the profuse{10-12}tensile twinning,and the relatively high dislocation density caused by the thermal stress during the WAAM process.
基金National Key Technology Research and Developmental Program of China(Program Nos.2022YFC2704400,2022YFC2704405)the Biomedical Ethics Committee of Peking University People's Hospital(approval number:IRB00001052-19142).
文摘Objective To investigate the molecular classification of endometrial cancer(EC)and atypical endometrial hyperplasia(AEH)patients treated with fertility-sparing treatment(FST),and its relationship with clinicopathological factors and treatment efficacy.Methods:A total of 52EC and AEH patients who received FST and molecular classification tested by next generation sequencing in Peking University People's Hospital from June 2020 to December 2022,were retrospectively collected.We analyzed the relationship between molecular classification and clinicopathological factors and treatment outcomes.Results(1)Of the 52 patients,including 46EC and 6 AEH patients,42(80.8%)achieved complete remission(CR)after FST,with a median time to achieve CR of 9 months.Ten cases(23.8%)had recurrence.(2)Patients were distributed into 4 molecular subgroups as 39 cases(75%)of copy number low(CNL),7 cases(13.5%)of microsatellite instability-high(MSI-H),4 cases(7.7%)of POLE mutations(POLEmut),and 2 cases(3.8%)of copy number high(CNH).Patients with MSI-H subgroup had more family history of tumor(6/7),more with loss of expression of mismatch repair(MMR)protein(7/7),and higher expression level of Ki-67(3/3).(3)Patients with MSI-H subgroup had the lowest CR rate at 6 months(0/7,P=0.014),and survival analysis showed that such patients were less likely to achieve CR than those with CNL(P=0.022).For CNL patients,median 6-month CR rate was 40.6%.In addition,CR was obtained in 3(3/4)POLEmut patients and 2(2/2)CNH patients,respectively.Conclusions Molecular classification relates with the treatment response in patients with EC and AEH receiving FST.Patients with MSI-H subgroup have poor treatment efficacy,and patients with CNL need to be further divided to predict treatment benefit.There are also a few successful cases in POLEmut and CNH subtgroups,which needs further research.
基金supported by the National Natural Science Foundation(Grant No.52005411)National Key R&D Program of China(Grant No.2016YFB1100100)the Research Fund of the State Key Laboratory of Solidification Processing,NPU,China(Grant No.2020-TZ-02).
文摘Quasicrystal(QC)-reinforced metal matrix composites fabricated by rapid solidification present promising new opportunities to develop high-strength alloys with multiple functions.In this research,specially designed Al–Fe–Cr samples possessing an Al–Fe–Cr quasicrystal-reinforced Al matrix structure were manufactured using a laser powder bed fusion(LPBF)process.Based on the optimized process parameters of laser scanning speed and hatch distance,an almost dense(99.8%)free-crack sample was obtained with the multiscaled heterogenous structure induced by the nonuniform rapid solidification in a single molten pool.The results show that nanosized Al–Fe–Cr quasicrystalline particles of different sizes are heterogeneously distributed in theα-Al columnar grain structure.In detail,the coarseflower-like and spherical QC particles can be observed at the molten pool boundary,and thefine spherical Al–Fe–Cr QC is located inside the laser fusion zone.The orientation relationship between the Al matrix and the icosahedral Al–Fe–Cr QC is as follows:Al[112]||i5 with a semicoherency feature.The novel designed LPBF-processed Al–Fe–Cr alloy exhibits high mechanical strength due to the ultrafine multireinforced microstructure-induced Orowan strengthening effect.For instance,the ultimate tensile strength,yield strength and elongation of the sample processed with LPBF are 530.803.19 MPa,395.066.44 MPa,and 4.16%0.38%,respectively.The fractographic analysis shows that the fracture mechanism presents a combination of ductile‒brittle fracture.
基金supported financially by the National Key R&D Program of China(No.2018YFB1105804)the Ningxia 13th Five Year Major Science and Technology Projects(Nos.2016BZ08 and 2018BCE01001).
文摘Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum alloy.The influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties were investigated.The results indicated that as the electric arc TS increased,the size and the volume fraction of equiaxed grain decreased.The high arc TS during WAAM also promoted the precipitation of theθ(Al2Cu)phase.The volume fractions ofθ’’andθ’phases reached maximum values when TS is 350 and 250 mm/min,respectively.The thermal cycle facilitated the precipitation of theθ’phase.In addition,the micro-hardness and tensile strength of the alloy were analyzed,and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength(273.5 MPa)and yield strength(182.9 MPa)compared to those fabricated at 250 mm/min.
基金financially supported by the National Key R&D Program of China(No.2018YFB1106300)the National Natural Science Foundation of China(No.51604227)the Fundamental Research Funds for the Central Universities(No.31020180QD130)。
文摘The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is underutilized.In this work,compared with the normal T6 heat treatment,a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary AlZr.It was found that a heterogeneous grain structure,which consisted of ultrafine equiaxed(~0.82μm)and columnar(~1.80μm)grains at the bottom and top of molten pool,respectively,was formed in the SLM processed sample.After direct aging(DA),the ultrafine grains were maintained and a mass of spherical coherent L1-AlZr particles with a mean radius of approximately1.15 nm was precipitated.In contrast,after solution treatment and aging(STA),a significant grain coarsening occurred in the equiaxed grain region.Meanwhile,the coarsening L1-AlZr particles,nano-sized S phases and GPB zones were detected in the STA sample.This subsequently induced that the yield strength of the DA sample(~435 MPa)was higher than that of the STA sample(~402 MPa)owing to the grain boundary strengthening and precipitation strengthening.Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6 alloy(~393 MPa).Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6alloy(~393 MPa).
基金the Project from the National Key Research and Development Program of China(Nos.2016YFB1100100 and 2018YFB1106300)。
文摘The control of grain morphology is important in laser additive manufacturing(LAM),as grain morphology further affects the hot cracking resistance,anisotropy,and strength–ductility synergy of materials.To develop a solidification-control solution and achieve columnar-to-equiaxed transition(CET)in Al-based alloys during LAM,Sc-and-Zr-modified Al-Mg alloys were processed via directed energy deposition(DED).CET was achieved by introducing high potent primary Al_(3)(Sc,Zr)nucleation sites ahead of the solidification interface.Furthermore,the relationship between the solidification control parameters and precipitation behavior of primary Al_(3)(Sc,Zr)nucleation sites was established using the time-dependent nucleation theory.Then,the CET was studied according to the Hunt criterion.The results indicated that coarse columnar grain structure was still obtained at the inner region of the molten pool at low Sc/Zr contents owing to the effective suppression of the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites via rapid solidification during DED.In addition,the relatively low melt temperature at the fusion boundary unavoidably promoted the precipitation of primary Al_(3)(Sc,Zr)nucleation sites,which resulted in a fine equiaxed grains band at the edge of the molten pool.As the Sc/Zr content increased,the solidification cooling rate was not sufficient to suppress the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites,and a fully equiaxed grain structure was obtained.Furthermore,the effect of the layer-by-layer manufacturing process on the subsequent precipitation strengthening of secondary Al_(3)(Sc,Zr)precipitates was discussed.Both the remelting and subsequent aging during thermal cycling should be considered to achieve greater precipitation strengthening.
基金financially supported by the National Key Research and Development Program of China(Nos.2018YFB1106302 and 2016YFB1100104)the National Natural Science Foundation of China(No.52005411)。
文摘Laser powder bed fusion(L-PBF)of Sc/Zr-modified Al-based alloys has recently become a promising method for developing a new generation of high-performance Al alloys.To clarify the modification roles of Sc/Zr elements,an Al–4.66Mg–0.48Mn–0.72Sc–0.33Zr(wt.%)alloy was processed using L-PBF.The effect of the local solidification condition of the molten pool on the precipitation behavior of primary Al_(3)(Sc,Zr)was analyzed based on time-dependent nucleation theory.It was found that primary Al_(3)(Sc,Zr)inevitably precipitated at the fusion boundary,while its precipitation could be effectively suppressed in the inner region of the molten pool.This subsequently induced the formation of a heterogeneousα-Al matrix.After direct aging,the heredity of solidification microstructure introduced heterogeneous secondary Al_(3)(Sc,Zr)precipitates withinα-Al matrix.Owing to the inverse relationship between grain boundary strengthening and precipitation strengthening,the direct-aged sample with dual heterogeneous structures exhibited reduced mechanical heterogeneity,resulting in lowered hetero-deformation-induced hardening.The low strain-hardening capability in the direct-aged sample promoted necking instability while inducing a large Lüders elongation,which effectively improved the tensile ductility.
文摘Hybrid manufacturing(HM)uses additive manufacturing(AM)techniques to prepare complex or fine structures on traditional processing parts,which can fully utilize the advantages of AM to form complex parts,and the high efficiency and low cost of conventional processing methods in manufacturing regular components.A bimetal material was produced by selective laser melting(SLM)of AlSi10Mg on the deformed Al6061 alloy substrate in this study.Firstly,the interface characteristics of the two alloys were studied.The results show that a metallurgical interface with a thickness of 100–200μm was formed as the result of the Marangoni convection during SLM preparation.In detail,the circular flow in the melt pool at the interface led to the dilution of alloying elements and the change of microstructure.Moreover,a suitable first-layer thickness can eff ectively suppress the hot cracks at the interfacial region.Based on the optimized results,the hybrid manufactured samples with diff erent SLM processed volume ratios(SLM-part)to the substrate were prepared to study the mechanical properties and the deformation behavior of hybrid parts.The results show that the volume ratio of the SLM-part to the substrate had an influence on the strength and the elasto-plastic behavior by aff ecting the distribution of plastic deformation.
文摘In the context of popularized healthcare,cloud computing centers are used to collect medical data from the cloud and diagnose illnesses.This means a technical framework that can be applied to the medical diagnostic process in popularized healthcare is needed in order to provide technical support.Based on the evidence fusion theory,this study established a multi-modality image evidence fusion method,which can simulate the doctor’s diagnostic process and use multiple modalities of medical images to diagnose illnesses.This study used the evidence fusion method to fuse two different modalities of medical images.The accuracy of the diagnosis after fusion was higher than that of diagnosis through two modalities separately.This fusion method has achieved great results in the process of multi-modality image fusion.
基金National Key R&D Program of China(Grant No.2018YFB0310400).
文摘Laser powder bed fusion(L-PBF)-processed high-silicon steel has great advantages in freely designed electric engines,and various studies have been conducted in this field.However,the analysis of both the mechanical and magnetic properties,focusing on the multiscale microstructure under as-fabricated and heat-treated conditions,which is indispensable for industrial applications,has not been performed.In this study,an Fe–Ni–Si sample was fabricated using the L-PBF process.Subsequently,the following hot isotropic pressing(HIPing)process was employed as a post heat treatment step for the Fe–Ni–Si alloys.The effects of HIPing on the microstructure were investigated,focusing on the metastable stable phase transformation in the Fe–Ni–Si system.X-ray diffraction results showed single-phase fccγ(Fe,Ni)in the L-PBF-processed samples before and after HIPing.Moreover,the acicular Ni/Si-rich structure(formed in the as-fabricated L-PBF sample because of its high cooling rates)transformed to the equilibrium austenite,Ni3Si,and FeNi3 phases during HIPing.After HIP,the compressive modulus and strength increased from 11 GPa and 650 MPa to approximately 18 GPa and 900 MPa,respectively.The magnetic properties were evaluated via a hysteresis loop,and the coercivity increased from 1.8 kA/m and to 2.9 kA/m after the HIPing process.
基金This work was supported by the National Key R&D Program of China(Grant No.2016YFB1100100)Fundamental Research Funds for the Central Universities(Grant No.31020180QD130)Production-Education-Research program of Aero Engine Corporation of China(Grant No.HFZL2019CXY019).
文摘In this study,the effect of triple-cycling heat treatment on the microstructure,phase,and compression behaviour of directed energy deposited(DED)Ti-7Mo alloy was investigated with a focus on a non-equilibrium to equilibrium microstructure transition.As a result of thermal accumulation,in situ cycling,and rapid solidification,the as-deposited sample presents a continuous gradient microstructure withα-Ti in the top region andα+βin the bottom region.After the triple-cycling heat treatment,theα+βTi at the bottom region,which is non-equilibrium,changes to a state of equilibrium nearα-Ti.Meanwhile,the microstructure becomes more uniform throughout the entire sample.The morphology of theα-Ti phase changes from acicular to a short rode-like shape with increases in the number of dimensions.In terms of the mechanical properties,both the microhardness and compression properties were improved,particularly with respect to the fracture characteristics.The heat-treated sample possesses a much higher ductility than the brittle fractural behaviour.This work provides new insights into the microstructure and property optimisation and homogenisation of DED-processed Ti-based components with cycling heat treatment.