The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces...The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has signif- icant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and inte- grated finishing and strengthening technologies and dis- cusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.展开更多
This research is focused on the study of the samples, approximatively 15 × 30 mm^2 sized, that were mechanically cut from two sheets (0.4 and 0.2 mm thick, respectively) of AIS1444 Type ferritic stainless steel...This research is focused on the study of the samples, approximatively 15 × 30 mm^2 sized, that were mechanically cut from two sheets (0.4 and 0.2 mm thick, respectively) of AIS1444 Type ferritic stainless steel (FSS) (DIN 1.4521, Eu designation X2CrMoTil8-2); this material was in the 'as-rolled' state. Part of these specimens were treated superficially on one side using abrasive SiC papers with different average grit sizes (i.e., 46.2, 30.2, 18.3 gm) and diamond suspension (up to 1 tim) in order to obtain various surface roughness. Both the 'as-rolled' and superficially treated samples were then aged in a muffle fumace in static air according to a thermal cycle corresponding to the curing phase of an experimental glass used as sealing in the solid oxide fuel cell stacks. After aging, the chemical compositions and mor- phological peculiarities of the scale formed depending on the thickness of the samples and their surface state were studied by scanning electron microscopy, energy-dispersive spectroscopy, micro-Raman spectroscopy, bright field light optical microscopy. The obtained results show that all scales formed consist of an inner Cr2O3 subscale and an outer (Mn,Cr)3O4 spinel layer; the relationship between FSS grain size and scale microstructural features is consistent on the samples with mirror-like surface only; the scale thicknesses on SiC grinded samples are comparable; the scales covering the 'as-rolled' surfaces are morphologically similar to those grown on the surfaces finished with the 30.2 and 18.3 μm SiC papers, and their thicknesses show an intermediate situation between the abraded and the mirror-like specimens. The last described characteristics depend mainly on the surface and microstructural peculiarities resulting from the rolling process.展开更多
The present investigation focuses on the parametric influence of machining parameters on the surface finish obtained in turning of glass fiber reinforced polymer (GFRP) composites. The experiments were conducted bas...The present investigation focuses on the parametric influence of machining parameters on the surface finish obtained in turning of glass fiber reinforced polymer (GFRP) composites. The experiments were conducted based on Taguchi's experimental design technique. Response surface methodology and analysis of variance (ANOVA) were used to evaluate the composite machining process to perform the optimization. The results revealed that the feed rate was main influencing parameter on the surface roughness. The surface roughness increased with increasing the feed rate but decreased with increasing the cutting speed. Among the other parameters, depth of cut was more insensitive. The predicted values and measured values were fairly close to each other, which indicates that the developed model can be effectively used to predict the surface roughness on the machining of GFRP composites with 95% confidence intervals. Using such model could remarkablely save the time and cost.展开更多
Ion beam irradiation was adopted for surface treatment of the micro punch manufactured by precision machining.Ar plasma was used for the ion irradiation process,which was generated by the electron cyclotron resonance(...Ion beam irradiation was adopted for surface treatment of the micro punch manufactured by precision machining.Ar plasma was used for the ion irradiation process,which was generated by the electron cyclotron resonance(ECR)equipment.The surface finish processes of micro punch were carried out at irradiation angles of 45°and 10°,respectively.The surface roughness and topography were measured to estimate the quality of surface finish.The results show that the ion irradiation is very effective to reduce the surface roughness,which can be improved more significantly at irradiation angle of 10°than at 45°.The technology of surface finish with ion beam irradiation is suitable for the surface treatment of micro die.展开更多
Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob le...Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob lem, an expert system approach is proposed, wherein it will be possible to predi ct the surface finish from limited experiments. The expert system contains a kno wledge base prepared from machining data handbooks and number of experiments con ducted by turning steel rods, over a wide range of cutting parameters. With this knowledge base, the expert system predicts surface finish for different tool-w ork-piece combinations, by carrying out few experiments for each case. The prop osed expert system model is validated by carrying out a number of experiments.展开更多
Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building ...Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building applications. The present review is a study on the influence of composite titanium on the cutting parameters, mechanical behavior, reinforcements, structure and nanostructure. This review will provide an understanding into selecting the optimum machining parameters for machining titanium composites. It’s also an attempt to give brief explanation by suitably machining the titanium composite which can be made reasonable.展开更多
The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a...The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.展开更多
This work focuses on the structure and magnetic properties of Fe-50wt% Ni permalloy manufactured from the pre-alloyed powder by selective laser melting (SLM). The selective laser melted (SLMed) alloys were characteriz...This work focuses on the structure and magnetic properties of Fe-50wt% Ni permalloy manufactured from the pre-alloyed powder by selective laser melting (SLM). The selective laser melted (SLMed) alloys were characterized by a 3D profilometer,optical microscope, scanning electron microscope, X-ray diffraction, etc. The effects of the volume energy density of laser(LVED) on structure, and magnetic properties with coercivity ( H), remanence ( B), and power losses ( P), were evaluated and discussed systematically. The results show that the relative porosity rate and the surface roughness of the SLMed specimens decreased with the increase in LVED. Only the γ-(FeNi) phase was detected in the X-ray diffraction patterns of the SLMed permalloys fabricated from the different LVEDs. Statistical analysis of optical microscopy images indicated that the grain coarsened at higher LVED. Furthermore, the microstructure of the SLMed parts was a typical columnar structure with an oriented growth of building direction. The highest microhardness reached 198 HV. Besides, the magnetic properties including B, H, and Pof SLMed samples decreased when the LVED ranged from 33.3 to 60.0 J/mm ~3 firstly and then increased while LVED further up to 93.3 J/mm, which is related to the decrease in porosity and the increase in grain size, while the higher residual stress and microcracks presented in the samples manufactured using very high LVED. The observed evolution of magnetic properties and LVED provides a good compromise in terms of reduced porosity and crack formation for the fabrication of SLMed Fe-50 wt% Ni permalloy. The theoretical mechanism in this study can offer guidance to further investigate SLMed soft magnetic alloys.展开更多
Uniform poly-α-methylstyrene(PAMS)hollow core microcapsules(HCMs)are widely used as templates to fabricate glow discharge polymer(GDP)fuel capsules,which are fundamental devices for inertial confinement fusion(ICF)en...Uniform poly-α-methylstyrene(PAMS)hollow core microcapsules(HCMs)are widely used as templates to fabricate glow discharge polymer(GDP)fuel capsules,which are fundamental devices for inertial confinement fusion(ICF)engineering.The sphericity and surface finish uniformity of PAMS HCMs are critical for achieving highquality GDP fuel capsules.In this work,millimeter-scale PAMS HCMs were fabricated by a microencapsulation technique.The sphericity and surface finish uniformity were concurrently improved using di-t-butyl peroxide(DTBP).The mechanisms of these effects were also experimentally and theoretically investigated.The results show that DTBP distributes at the O-W2 interface of W1/O/W2 compound droplets,which resists the diffusion of molecules through the O-W2 interface bidirectionally.The resisted diffusion of H_(2)O molecules into the O phase eliminates PAMS HCM surface defects.Additionally,the resistance of fluorobenzene(FB)molecules from diffusing from the O phase into the W2 phase can effectively extend the solidification of W1/O/W2 compound droplets and thus improve the spherical uniformity of the HCMs.Using these improved PAMS HCMs,GDP fuel capsules meeting the stringent requirements for ICF engineering are prepared,and the quality of which is beyond the National Ignition Facility standard.展开更多
The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray ph...The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes (electropolished, mechanically polished, ground, and as-received) were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.展开更多
This paper presents an approach for determiningthe optimal cutting condition for milling thin-walled ele-ments with complex shapes. The approach is based on theinteraction between the thin-walled detail and its period...This paper presents an approach for determiningthe optimal cutting condition for milling thin-walled ele-ments with complex shapes. The approach is based on theinteraction between the thin-walled detail and its periodicexcitation by tooth passing, taking into account the highintermittency of such a process. The influence of theexcitation frequency on the amplitude of the detail oscil-lation during milling was determined by simulation andexperiments. It was found that the analytical results agreedwith experimental data. The position of the detail when thetooth starts to cut was evaluated through experiments. Theinfluence of this parameter on the processing state is pre-sented herein. The processing stability is investigated andcompared with the proposed approach. Thereafter, spectralanalyses are conducted to determine the contribution of thevibrating frequencies to the detail behavior during processing.展开更多
基金Supported by Science Fund for Creative Research Groups of NSFC(51621064)National Natural Science Foundation of China(Grant No.51475074,11302043)the Fundamental Research Funds for the Central Universities(DUT15QY37)
文摘The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has signif- icant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and inte- grated finishing and strengthening technologies and dis- cusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.
基金funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) Fuel Cells and Hydrogen Joint Undertaking (FCH-JU-2013-1) under Grant Agreement No. 621207
文摘This research is focused on the study of the samples, approximatively 15 × 30 mm^2 sized, that were mechanically cut from two sheets (0.4 and 0.2 mm thick, respectively) of AIS1444 Type ferritic stainless steel (FSS) (DIN 1.4521, Eu designation X2CrMoTil8-2); this material was in the 'as-rolled' state. Part of these specimens were treated superficially on one side using abrasive SiC papers with different average grit sizes (i.e., 46.2, 30.2, 18.3 gm) and diamond suspension (up to 1 tim) in order to obtain various surface roughness. Both the 'as-rolled' and superficially treated samples were then aged in a muffle fumace in static air according to a thermal cycle corresponding to the curing phase of an experimental glass used as sealing in the solid oxide fuel cell stacks. After aging, the chemical compositions and mor- phological peculiarities of the scale formed depending on the thickness of the samples and their surface state were studied by scanning electron microscopy, energy-dispersive spectroscopy, micro-Raman spectroscopy, bright field light optical microscopy. The obtained results show that all scales formed consist of an inner Cr2O3 subscale and an outer (Mn,Cr)3O4 spinel layer; the relationship between FSS grain size and scale microstructural features is consistent on the samples with mirror-like surface only; the scale thicknesses on SiC grinded samples are comparable; the scales covering the 'as-rolled' surfaces are morphologically similar to those grown on the surfaces finished with the 30.2 and 18.3 μm SiC papers, and their thicknesses show an intermediate situation between the abraded and the mirror-like specimens. The last described characteristics depend mainly on the surface and microstructural peculiarities resulting from the rolling process.
文摘The present investigation focuses on the parametric influence of machining parameters on the surface finish obtained in turning of glass fiber reinforced polymer (GFRP) composites. The experiments were conducted based on Taguchi's experimental design technique. Response surface methodology and analysis of variance (ANOVA) were used to evaluate the composite machining process to perform the optimization. The results revealed that the feed rate was main influencing parameter on the surface roughness. The surface roughness increased with increasing the feed rate but decreased with increasing the cutting speed. Among the other parameters, depth of cut was more insensitive. The predicted values and measured values were fairly close to each other, which indicates that the developed model can be effectively used to predict the surface roughness on the machining of GFRP composites with 95% confidence intervals. Using such model could remarkablely save the time and cost.
基金Project(2006AA04Z331)supported by the Hi-tech Research and Development Program of ChinaProject(50835002)supported by theKey Program of the National Natural Science Foundation of ChinaProject(JC-06-07)supported by the Science Foundation for Distinguished Young Scholars of Heilongjiang Province,China。
文摘Ion beam irradiation was adopted for surface treatment of the micro punch manufactured by precision machining.Ar plasma was used for the ion irradiation process,which was generated by the electron cyclotron resonance(ECR)equipment.The surface finish processes of micro punch were carried out at irradiation angles of 45°and 10°,respectively.The surface roughness and topography were measured to estimate the quality of surface finish.The results show that the ion irradiation is very effective to reduce the surface roughness,which can be improved more significantly at irradiation angle of 10°than at 45°.The technology of surface finish with ion beam irradiation is suitable for the surface treatment of micro die.
文摘Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob lem, an expert system approach is proposed, wherein it will be possible to predi ct the surface finish from limited experiments. The expert system contains a kno wledge base prepared from machining data handbooks and number of experiments con ducted by turning steel rods, over a wide range of cutting parameters. With this knowledge base, the expert system predicts surface finish for different tool-w ork-piece combinations, by carrying out few experiments for each case. The prop osed expert system model is validated by carrying out a number of experiments.
文摘Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building applications. The present review is a study on the influence of composite titanium on the cutting parameters, mechanical behavior, reinforcements, structure and nanostructure. This review will provide an understanding into selecting the optimum machining parameters for machining titanium composites. It’s also an attempt to give brief explanation by suitably machining the titanium composite which can be made reasonable.
文摘The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.
基金financially supported by the Sciences Platform Environment and Capacity Building Projects of GDAS(No.2021GDASYL-20210102005)the Guangdong Special Support Program(No.2019BT02C629)+2 种基金the GuangDong Basic and Applied Basic Research Foundation(Nos.2020A1515111031 and 2021A515010939)the Guangzhou Major Projects of Industry University-Research(IUR)Collaborative Innovation“Surface Treatment and Repair for Key Components of Industrial Gas Turbine(IGT).”support from the program of CSC(No.201801810066)support from the program of CSC(No.201801810106)。
文摘This work focuses on the structure and magnetic properties of Fe-50wt% Ni permalloy manufactured from the pre-alloyed powder by selective laser melting (SLM). The selective laser melted (SLMed) alloys were characterized by a 3D profilometer,optical microscope, scanning electron microscope, X-ray diffraction, etc. The effects of the volume energy density of laser(LVED) on structure, and magnetic properties with coercivity ( H), remanence ( B), and power losses ( P), were evaluated and discussed systematically. The results show that the relative porosity rate and the surface roughness of the SLMed specimens decreased with the increase in LVED. Only the γ-(FeNi) phase was detected in the X-ray diffraction patterns of the SLMed permalloys fabricated from the different LVEDs. Statistical analysis of optical microscopy images indicated that the grain coarsened at higher LVED. Furthermore, the microstructure of the SLMed parts was a typical columnar structure with an oriented growth of building direction. The highest microhardness reached 198 HV. Besides, the magnetic properties including B, H, and Pof SLMed samples decreased when the LVED ranged from 33.3 to 60.0 J/mm ~3 firstly and then increased while LVED further up to 93.3 J/mm, which is related to the decrease in porosity and the increase in grain size, while the higher residual stress and microcracks presented in the samples manufactured using very high LVED. The observed evolution of magnetic properties and LVED provides a good compromise in terms of reduced porosity and crack formation for the fabrication of SLMed Fe-50 wt% Ni permalloy. The theoretical mechanism in this study can offer guidance to further investigate SLMed soft magnetic alloys.
基金This work was supported by the National Natural Science Foundation of China(52036006,51725602 and 22002145)the Young Talents Program of Laser Fusion Research Center and the Open Project of State Key Laboratory of Environment-friendly Energy Materials(21kfhg03).
文摘Uniform poly-α-methylstyrene(PAMS)hollow core microcapsules(HCMs)are widely used as templates to fabricate glow discharge polymer(GDP)fuel capsules,which are fundamental devices for inertial confinement fusion(ICF)engineering.The sphericity and surface finish uniformity of PAMS HCMs are critical for achieving highquality GDP fuel capsules.In this work,millimeter-scale PAMS HCMs were fabricated by a microencapsulation technique.The sphericity and surface finish uniformity were concurrently improved using di-t-butyl peroxide(DTBP).The mechanisms of these effects were also experimentally and theoretically investigated.The results show that DTBP distributes at the O-W2 interface of W1/O/W2 compound droplets,which resists the diffusion of molecules through the O-W2 interface bidirectionally.The resisted diffusion of H_(2)O molecules into the O phase eliminates PAMS HCM surface defects.Additionally,the resistance of fluorobenzene(FB)molecules from diffusing from the O phase into the W2 phase can effectively extend the solidification of W1/O/W2 compound droplets and thus improve the spherical uniformity of the HCMs.Using these improved PAMS HCMs,GDP fuel capsules meeting the stringent requirements for ICF engineering are prepared,and the quality of which is beyond the National Ignition Facility standard.
基金supported by the Special Funds for the Major State Basic Research Projects(G2011CB610502)the National Natural Science Foundation of China (No.51025104)
文摘The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes (electropolished, mechanically polished, ground, and as-received) were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.
文摘This paper presents an approach for determiningthe optimal cutting condition for milling thin-walled ele-ments with complex shapes. The approach is based on theinteraction between the thin-walled detail and its periodicexcitation by tooth passing, taking into account the highintermittency of such a process. The influence of theexcitation frequency on the amplitude of the detail oscil-lation during milling was determined by simulation andexperiments. It was found that the analytical results agreedwith experimental data. The position of the detail when thetooth starts to cut was evaluated through experiments. Theinfluence of this parameter on the processing state is pre-sented herein. The processing stability is investigated andcompared with the proposed approach. Thereafter, spectralanalyses are conducted to determine the contribution of thevibrating frequencies to the detail behavior during processing.