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Evolution of microstructure and texture of AZ80 magnesium alloy under hot torsion with constant decreasing temperature rate
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作者 Yongbiao Yang Jinxuan Guo +4 位作者 Cuiying Wang Wenxuan Jiang Zhimin Zhang Qiang Wang Xing Zhang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第4期1619-1637,共19页
Hot torsion tests for AZ80 magnesium alloy were carried out in the temperature range of 380℃-260℃,with a constant decreasing temperature rate of 10℃/s in order to weaken the basal texture and refine the grains.The ... Hot torsion tests for AZ80 magnesium alloy were carried out in the temperature range of 380℃-260℃,with a constant decreasing temperature rate of 10℃/s in order to weaken the basal texture and refine the grains.The results indicated that the average grain sizes were refined forming gradient structure with increasing specimen radial position from center(12.2-5.4μm),and that the initial basal texture intensity of the extruded magnesium alloy was weakened from 46.2 to 8.3.Furthermore,the extension twins(ETs)could be disintegrated from the twins forming separated twins with smaller sizes.Interestingly,ETs with the same twin variant intersecting with each other could be coalesced forming grains with similar orientation,while ETs with different twin variants were separated by twins boundaries contributing to grain refinement.Moreover,in addition to the conventional continuous dynamic recrystallized(CDRX)grains with 30˚orientation rotated around C-axis of the parent grains,CDRXed grains with 30˚rotation around a-axis and random rotation axis were also discerned.Besides,the CDRX evolution induced twins were also elaborated,exhibiting the complex competition between CDRX and twining.Hot torsion deformation with constant decreasing temperatures rate is an effective way of grain refinement and texture modification. 展开更多
关键词 Texture Microstructure Hot torsion Decreasing temperature AZ80
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Nano-scale Reinforcements and Properties of Al-Si-Cu Alloy Processed by High-Pressure Torsion
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作者 DONG Ying WU Siyuan +4 位作者 HE Ziyang LIANG Chen CHENG Feng HE Zuwei QIAN Chenhao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1253-1259,共7页
To improve the comprehensive mechanical properties of Al-Si-Cu alloy,it was treated by a high-pressure torsion process,and the effect of the deformation degree on the microstructure and properties of the Al-Si-Cu allo... To improve the comprehensive mechanical properties of Al-Si-Cu alloy,it was treated by a high-pressure torsion process,and the effect of the deformation degree on the microstructure and properties of the Al-Si-Cu alloy was studied.The results show that the reinforcements(β-Si andθ-CuAl_(2)phases)of the Al-Si-Cu alloy are dispersed in theα-Al matrix phase with finer phase size after the treatment.The processed samples exhibit grain sizes in the submicron or even nanometer range,which effectively improves the mechanical properties of the material.The hardness and strength of the deformed alloy are both significantly raised to 268 HV and 390.04 MPa by 10 turns HPT process,and the fracture morphology shows that the material gradually transits from brittle to plastic before and after deformation.The elements interdiffusion at the interface between the phases has also been effectively enhanced.In addition,it is found that the severe plastic deformation at room temperature induces a ternary eutectic reaction,resulting in the formation of ternary Al+Si+CuAl_(2)eutectic. 展开更多
关键词 Al-Si-Cu alloy high-pressure torsion nano-scale reinforcements ternary eutectic
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Clinical characteristics of testicular torsion and factors influencing testicular salvage in children:A 12-year study in tertiary center
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作者 Xiang-Hui Gang Yuan-Yuan Duan +5 位作者 Bin Zhang Zheng-Gan Jiang Rong Zhang Jun Chen Xiang-Yu Teng Duo-Bing Zhang 《World Journal of Clinical Cases》 SCIE 2024年第7期1251-1259,共9页
BACKGROUND Testicular torsion is the most common acute scrotum worldwide and mainly occurs in children and adolescents.Studies have demonstrated that the duration of symptoms and torsion grade lead to different outcom... BACKGROUND Testicular torsion is the most common acute scrotum worldwide and mainly occurs in children and adolescents.Studies have demonstrated that the duration of symptoms and torsion grade lead to different outcomes in children diagnosed with testicular torsion.AIM To predict the possibility of testicular salvage(TS)in patients with testicular torsion in a tertiary center.METHODS We reviewed the charts of 75 pediatric patients with acute testicular torsion during a 12-year period from November 2011 to July 2023 at the Suzhou Hospital of Anhui Medical University.Univariate and multivariate logistic regression analyses were used to determine independent predictors of testicular torsion.The data included clinical findings,physical examinations,laboratory data,color Doppler ultrasound findings,operating results,age,presenting institution status,and follow-up results.RESULTS Our study included 75 patients.TS was possible in 57.3%of all patients;testicular torsion occurred mostly in winter,and teenagers aged 11-15 years old accounted for 60%.Univariate logistic regression analyses revealed that younger age(P=0.09),body mass index(P=0.004),torsion angle(P=0.013),red blood cell count(P=0.03),neutrophil-to-lymphocyte ratio(P=0.009),and initial presenting institution(P<0.001)were associated with orchiectomy.In multivariate analysis,only the initial presenting institution predicted TS(P<0.05).CONCLUSION The initial presenting institution has a predictive value for predicting TS in patients with testicular torsion.Children with scrotal pain should be admitted to a tertiary hospital as soon as possible. 展开更多
关键词 Testicular torsion Testicular salvage PEDIATRICS PREDICTORS Case report
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Two-stage dynamic recrystallization and texture evolution in Al-7Mg alloy during hot torsion
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作者 Kwang Tae Son Chang Hee Cho +1 位作者 Myoung Gyun Kim Ji Woon Lee 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第8期1900-1911,共12页
Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500℃ and strain rates between 0.05 and 5 s^(-1) to explore the progressive dynamic recrystallization(DRX)and texture behavio... Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500℃ and strain rates between 0.05 and 5 s^(-1) to explore the progressive dynamic recrystallization(DRX)and texture behaviors.The DRX behavior of the alloy manifested two distinct stages:Stage 1 at strain of≤2 and Stage 2 at strains of≥2.In Stage 1,there was a slight increase in the DRXed grain fraction(X_(DRX))with predominance of discontinuous DRX(DDRX),followed by a modest change in X_(DRX) until the transition to Stage 2.Stage 2 was marked by an accelerated rate of DRX,culminating in a substantial final X_(DRX) of~0.9.Electron backscattered diffraction(EBSD)analysis on a sample in Stage 2 revealed that continuous DRX(CDRX)predominantly occurred within the(121)[001]grains,whereas the(111)[110]grains underwent a geometric DRX(GDRX)evolution without a noticeable sub-grain structure.Furthermore,a modified Avrami’s DRX kinetics model was utilized to predict the microstructural refinement in the Al-7Mg alloy during the DRX evolution.Although this kinetics model did not accurately capture the DDRX behavior in Stage 1,it effectively simulated the DRX rate in Stage 2.The texture index was employed to assess the evolution of the texture isotropy during hot-torsion test,demonstrating significant improvement(>75%)in texture randomness before the commencement of Stage 2.This initial texture evolution is attributed to the rotation of parent grains and the substructure evolution,rather than to an increase in X_(DRX). 展开更多
关键词 Al-7Mg alloys hot deformation hot torsion tests dynamic recrystazlliation microstructure texture
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Multi-objective optimization design of anti-roll torsion bar using improved beluga whale optimization algorithm
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作者 Yonghua Li Zhe Chen +1 位作者 Maorui Hou Tao Guo 《Railway Sciences》 2024年第1期32-46,共15页
Purpose – This study aims to reduce the redundant weight of the anti-roll torsion bar brought by thetraditional empirical design and improving its strength and stiffness.Design/methodology/approach – Based on the fi... Purpose – This study aims to reduce the redundant weight of the anti-roll torsion bar brought by thetraditional empirical design and improving its strength and stiffness.Design/methodology/approach – Based on the finite element approach coupled with the improved belugawhale optimization (IBWO) algorithm, a collaborative optimization method is suggested to optimize the designof the anti-roll torsion bar structure and weight. The dimensions and material properties of the torsion bar weredefined as random variables, and the torsion bar’s mass and strength were investigated using finite elements.Then, chaotic mapping and differential evolution (DE) operators are introduced to improve the beluga whaleoptimization (BWO) algorithm and run case studies.Findings – The findings demonstrate that the IBWO has superior solution set distribution uniformity,convergence speed, solution correctness and stability than the BWO. The IBWO algorithm is used to optimizethe anti-roll torsion bar design. The error between the optimization and finite element simulation results wasless than 1%. The weight of the optimized anti-roll torsion bar was lessened by 4%, the maximum stress wasreduced by 35% and the stiffness was increased by 1.9%.Originality/value – The study provides a methodological reference for the simulation optimization process ofthe lateral anti-roll torsion bar. 展开更多
关键词 Anti-roll torsion bar Multi-objective optimization IBWO Chaotic mapping Differential evolution
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Rupture of a giant jejunal mesenteric cystic lymphangioma misdiagnosed as ovarian torsion: A case report
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作者 Jing Xu Tie-Feng Lv 《World Journal of Clinical Cases》 SCIE 2024年第4期847-852,共6页
BACKGROUND Cystic lymphangioma is a rare benign tumor that affects the lymphatic system.Mesenteric lymphangiomas in the small bowel are extremely uncommon.CASE SUMMARY We present a 21-year-old female patient who compl... BACKGROUND Cystic lymphangioma is a rare benign tumor that affects the lymphatic system.Mesenteric lymphangiomas in the small bowel are extremely uncommon.CASE SUMMARY We present a 21-year-old female patient who complained of abdominal pain.The diagnosis of ovarian torsion was suspected after abdominopelvic unenhanced computed tomography and ultrasound revealed a large cyst in contact with the bladder,ovary,and uterus.The patient underwent emergency laparotomy per-formed by gynecologists,but it was discovered that the cystic tumor originated from the jejunum.Gastrointestinal surgeons were then called in to perform a cystectomy.Pathological examination confirmed the diagnosis of cystic lymphangioma of the mesentery.The patient had an uneventful postoperative recovery.CONCLUSION Mesenteric lymphangiomas can cause abdominal pain,and imaging techniques can help determine their characteristics,location,and size.Complete surgical excision and pathological examination are considered the standard treatment and diagnostic method. 展开更多
关键词 RUPTURE JEJUNUM Mesenteric cystic lymphangioma Ovarian torsion Surgical excision Pathological examination Case report
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Analysis of strength characteristics of loess before and after freezing using a hollow cylinder torsional shear apparatus
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作者 Peng Shen QingZhi Wang +2 位作者 JianHong Fang ChenWei Wang Kui Zhang 《Research in Cold and Arid Regions》 CSCD 2024年第2期63-72,共10页
This paper aims to comprehensively analyze the influence of the principal stress angle rotation and intermediate principal stress on loess's strength and deformation characteristics. A hollow cylinder torsional sh... This paper aims to comprehensively analyze the influence of the principal stress angle rotation and intermediate principal stress on loess's strength and deformation characteristics. A hollow cylinder torsional shear apparatus was utilized to conduct tests on remolded samples under both normal and frozen conditions to investigate the mechanical properties and deformation behavior of loess under complex stress conditions. The results indicate significant differences in the internal changes of soil particles, unfrozen water, and relative positions in soil samples under normal and frozen conditions, leading to noticeable variations in strength and strain development.In frozen state, loess experiences primarily compressive failure with a slow growth of cracks, while at normal temperature, it predominantly exhibits shear failure. With the increase in the principal stress angle, the deformation patterns of the soil samples under different conditions become essentially consistent, gradually transitioning from compression to extension, accompanied by a reduction in axial strength. The gradual increase in the principal stress axis angle(α) reduces the strength of the generalized shear stress and shear strain curves.Under an increasing α, frozen soil exhibits strain-hardening characteristics, with the maximum shear strength occurring at α = 45°. The intermediate principal stress coefficient(b) also significantly impacts the strength of frozen soil, with an increasing b resulting in a gradual decrease in generalized shear stress strength. This study provides a reference for comprehensively exploring the mechanical properties of soil under traffic load and a reliable theoretical basis for the design and maintenance of roadbeds. 展开更多
关键词 LOESS Hollow cylinder torsional shear apparatus Major principal stress angle Intermediate principal stress coefficient
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The Effects of the Longitudinal Axis of Loading upon Bending, Shear and Torsion of a Thin-Walled Cantilever Channel Beam
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作者 David W. A. Rees Abdelraouf M. Sami Alsheikh 《World Journal of Mechanics》 2024年第5期73-96,共24页
Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoreticall... Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section. 展开更多
关键词 Thin-Aluminium Channels Cantilever Beam Bending Shear torsion WARPING BIMOMENT Flexural Axis Centre of Twist CENTROID Shear Centre torsional Stiffness Constrained Stress
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Theory of Flexural Shear, Bending and Torsion for a Thin-Walled Beam of Open Section
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作者 David W. A. Rees Abdelraouf M. Sami Alsheikh 《World Journal of Mechanics》 2024年第3期23-53,共31页
Aspects of the general Vlasov theory are examined separately as applied to a thin-walled channel section cantilever beam under free-end end loading. In particular, the flexural bending and shear that arise under trans... Aspects of the general Vlasov theory are examined separately as applied to a thin-walled channel section cantilever beam under free-end end loading. In particular, the flexural bending and shear that arise under transverse shear and axial torsional loading are each considered theoretically. These analyses involve the location of the shear centre at which transverse shear forces when applied do not produce torsion. This centre, when taken to be coincident with the centre of twist implies an equivalent reciprocal behaviour. That is, an axial torsion applied concentric with the shear centre will twist but not bend the beam. The respective bending and shear stress conversions are derived for each action applied to three aluminium alloy extruded channel sections mounted as cantilevers with a horizontal principal axis of symmetry. Bending and shear are considered more generally for other thin-walled sections when the transverse loading axes at the shear centre are not parallel to the section = s centroidal axes of principal second moments of area. The fixing at one end of the cantilever modifies the St Venant free angular twist and the free warping displacement. It is shown from the Wagner-Kappus torsion theory how the end constrained warping generates an axial stress distribution that varies with the length and across the cross-section for an axial torsion applied to the shear centre. It should be mentioned here for wider applications and validation of the Vlasov theory that attendant papers are to consider in detail bending and torsional loadings applied to other axes through each of the centroid and the web centre. Therein, both bending and twisting arise from transverse shear and axial torsion applied to each position being displaced from the shear centre. Here, the influence of the axis position upon the net axial and shear stress distributions is to be established. That is, the net axial stress from axial torsional loading is identified with the sum of axial stress due to bending and axial stress arising from constrained warping displacements at the fixing. The net shear stress distribution overlays the distributions from axial torsion and that from flexural shear under transverse loading. Both arise when transverse forces are displaced from the shear centre. 展开更多
关键词 Thin Wall Theory Cantilever Beam Open Channel Section Principal Axes Flexure Transverse Shear torsion Shear Centre Shear Flow WARPING Fixed-End Constraint
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Influence of twist extrusion process on consolidation of pure aluminum powder in tubes by equal channel angular pressing and torsion 被引量:4
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作者 王晓溪 何敏 +2 位作者 朱珍 薛克敏 李萍 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2122-2129,共8页
In comparison with the conventional equal channel angular pressing(ECAP) process,a comprehensive study of influence of twist extrusion(TE) process on consolidating pure aluminum powder in tubes(PITs) by equal ch... In comparison with the conventional equal channel angular pressing(ECAP) process,a comprehensive study of influence of twist extrusion(TE) process on consolidating pure aluminum powder in tubes(PITs) by equal channel angular pressing and torsion(ECAPT) was conducted via three-dimensional(3D) finite element simulation,experimental investigation and theoretical analysis.Simulation results revealed that during the consolidation of aluminum powder particles by ECAPT,TE process played a significant role of back pressure.Due to the torsional shear and high hydrostatic pressure exerted by twist channel,both the magnitude and homogeneity of the effective strain were increased markedly.After one pass of ECAPT process using a square channel with an inner angle of 90° and a twist slope angle of 36.5° at 200℃,commercial pure aluminum powder particles were successfully consolidated to nearly full density.Simulation and experimental results showed good agreement.In the microstructure observations,grains were greatly refined.At the same time,porosities were effectively eliminated by shrinking in size and breaking into small ones.Microhardness test indicated that strain distribution of ECAPT-processed billet was more homogeneous with respect to the ECAP-processed one.All these improvements may be attributed to the extreme intense shear strain induced during ECAPT and the increase in self-diffusion coefficient of aluminum due to the back pressure exerted by TE process. 展开更多
关键词 aluminum powder equal channel angular pressing and torsion powder consolidation back pressure
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Torsional超声乳化模式治疗硬核白内障 被引量:1
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作者 张祺 程旭康 王晋瑛 《眼科新进展》 CAS 北大核心 2009年第4期297-298,共2页
目的探讨Torsional超声乳化模式治疗硬核白内障的效果。方法将220例(285眼)行白内障超声乳化术的硬核白内障患者随机分为普通超声乳化模式组与Torsional超声乳化模式组,比较术中晶状体核乳化时间和灌注液用量,术后检查记录角膜内皮细胞... 目的探讨Torsional超声乳化模式治疗硬核白内障的效果。方法将220例(285眼)行白内障超声乳化术的硬核白内障患者随机分为普通超声乳化模式组与Torsional超声乳化模式组,比较术中晶状体核乳化时间和灌注液用量,术后检查记录角膜内皮细胞丢失率、最佳矫正视力。结果普通模式组术中晶状体核乳化时间平均164s,Torsional模式组平均117s;灌注液用量普通模式组为93mL,Torsional模式组为41mL;2组比较差异均有统计学意义(P<0.05)。术后1周角膜内皮细胞丢失率Torsional模式组为11.8%,普通模式组为20.3%,差异有统计学意义(P<0.05)。术后第1天和第30天Torsional模式组平均最佳矫正视力为0.4和0.6,普通模式组为0.1和0.4。结论Torsional超声乳化模式治疗硬核白内障与普通超声乳化模式相比,可以减少超声乳化时间、灌注液用量,从而降低角膜内皮细胞的丢失率,提高术后视力效果。 展开更多
关键词 torsional超声乳化 硬核 白内障
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Microstructure evolution and dislocation configurations in nanostructured Al-Mg alloys processed by high pressure torsion 被引量:3
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作者 刘满平 蒋婷慧 +3 位作者 谢学锋 刘强 李雪峰 Hans J.ROVEN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第12期3848-3857,共10页
Microstructure evolution and dislocation configurations in nanostructured Al–Mg alloys processed by high pressure torsion (HPT) were analyzed by transmission electron microscopy (TEM) and high-resolution TEM (HR... Microstructure evolution and dislocation configurations in nanostructured Al–Mg alloys processed by high pressure torsion (HPT) were analyzed by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The results show that the grains less than 100 nm have sharp grain boundaries (GBs) and are completely free of dislocations. In contrast, a high density of dislocation as high as 1017 m^-2 exists within the grains larger than 200 nm and these larger grains are usually separated into subgrains and dislocation cells. The dislocations are 60° full dislocations with Burgers vectors of 1/2〈110〉and most of them appear as dipoles and loops. The microtwins and stacking faults (SFs) formed by the Shockley partials from the dissociation of both the 60° mixed dislocation and 0° screw dislocation in ultrafine grains were simultaneously observed by HRTEM in the HPT Al–Mg alloys. These results suggest that partial dislocation emissions, as well as the activation of partial dislocations could also become a deformation mechanism in ultrafine-grained aluminum during severe plastic deformation. The grain refinement mechanism associated with the very high local dislocation density, the dislocation cells and the non-equilibrium GBs, as well as the SFs and microtwins in the HPT Al-Mg alloys were proposed. 展开更多
关键词 Al-Mg aluminum alloy severe plastic deformation high pressure torsion dislocation configurations grain refinement deformation mechanism
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GIGACYCLE FATIGUE BEHAVIOR OF CAST ALUMINUM IN TENSION AND TORSION LOADING 被引量:3
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作者 薛红前 吴铁鹰 Bathias C 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第1期32-37,共6页
An improved understanding of fatigue behavior of a cast aluminum alloy(2-AS5U3G-Y35)in very high cycle regime is developed through the ultrasonic fatigue test in axial and torsion loading.The new developed torsion f... An improved understanding of fatigue behavior of a cast aluminum alloy(2-AS5U3G-Y35)in very high cycle regime is developed through the ultrasonic fatigue test in axial and torsion loading.The new developed torsion fatigue system is presented.The effects of loading condition and frequency on the very high cycle fatigue(VHCF)are investigated.The cyclic loading in axial and torsion at 35 Hz and 20 kHz with stress ratio R=-1 is used respectively to demonstrate the effect of loading condition.S-N curves show that the fatigue failure occurs in the range of 105—1010 cycles in axial or torsion loading and the asymptote of S-N curve is inclined,but no fatigue limit exists under the torsion and axial loading condition.The fatigue fracture surface shows that the fatigue crack initiates from the specimen surface subjected to the cyclic torsion loading.It is different from the fatigue fracture characteristic in axial loading in which fatigue crack initiates from subsurface defect in very high cycle regime.The fatigue initiation is on the maximum shear plane,the overall crack orientation is on a typical spiral 45° to the fracture plane and it is the maximum principle stress plane.The clear shear strip in the torsion fatigue fracture surface shows that the torsion fracture is the shear fracture. 展开更多
关键词 fatigue testing torsion fatigue very high cycle fatigue(VHCF) torsion loading cast aluminum
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Enhanced ductility and reduced asymmetry of Mg-2Al-1Zn alloy plate processed by torsion and annealing 被引量:1
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作者 王军 杨续跃 +3 位作者 李祎 肖振宇 张笃秀 Taku SAKAI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第12期3928-3935,共8页
The ductility and plastic asymmetry of an as-annealed magnesium alloy plate were studied in compression through combined process of torsion and subsequent annealing by optical microscope and EBSD. The yield strength... The ductility and plastic asymmetry of an as-annealed magnesium alloy plate were studied in compression through combined process of torsion and subsequent annealing by optical microscope and EBSD. The yield strength(YS) and ultimate compression strength(UCS) as well as the compression ductility(CD) were simultaneously raised by prior torsion at room temperature. The CD was further enhanced by subsequent annealing. Also, the torqued sample followed by annealing experienced a rising CD with the increase in prior strain, leading to the maximum true strain of 0.279, which is twice that of the as-annealed original one. The sample showed a largely reduced tension-compression yield asymmetry by subjecting to pre-torsion alone or combined with a subsequent annealing. The enhanced ductility and reduced asymmetry are attributed to the development of a gradient microstructure with refined grains, and also randomization of the weakened texture due to torsion and subsequent annealing. 展开更多
关键词 magnesium alloy microstructure torsion asymmetry texture TWINNING
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Refinement and consolidation of pure Al particles by equal channel angular pressing and torsion 被引量:1
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作者 李萍 薛克敏 +1 位作者 王晓溪 钱陈豪 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1289-1294,共6页
Consolidation of pure Alpowder was conducted at 200 ℃ by equal channel angular pressing and torsion (ECAPT) method. The grain refinement and consolidation behavior were deeply investigated by scan electronic micros... Consolidation of pure Alpowder was conducted at 200 ℃ by equal channel angular pressing and torsion (ECAPT) method. The grain refinement and consolidation behavior were deeply investigated by scan electronic microscopy (SEM) and transmission electronic microscopy (TEM). The density, hardness and room temperature compression properties of the deformed samples were measured. The experiment results show that ECAPT is an effective method of consolidating powders at relatively low temperatures. Pure A1 particles are successfully consolidated into dense bulk material after 4 passes of ECAPT at 200 ℃. The consolidated material possesses fine grain structure and excellent mechanical properties. The refinement and consolidation mechanisms were analyzed. ECAPT is a promising method to produce the high-performance bulk materials from particles. 展开更多
关键词 REFINEMENT CONSOLIDATION equal channel angular pressing and torsion Al powder
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三角范畴和Abel范畴的Torsion理论 被引量:2
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作者 林记 姚云飞 《数学杂志》 CSCD 北大核心 2014年第6期1134-1140,共7页
本文主要研究了三角范畴在Abel化过程中torsion理论的保持问题.利用三角范畴的coherent函子范畴是Abel范畴,证明了T的coherent函子范畴A(T)是A(D)的thick子范畴;若(X,Y)是D的torsion理论,且D=X*Y的扩张是可裂的,那么(A(X),A(Y))是A(D)的... 本文主要研究了三角范畴在Abel化过程中torsion理论的保持问题.利用三角范畴的coherent函子范畴是Abel范畴,证明了T的coherent函子范畴A(T)是A(D)的thick子范畴;若(X,Y)是D的torsion理论,且D=X*Y的扩张是可裂的,那么(A(X),A(Y))是A(D)的torsion理论. 展开更多
关键词 三角范畴 coherent函子范畴 thick子范畴 torsion理论
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环的相对于余遗传Torsion Theory的Jacobson根
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作者 赵文正 《河南师范大学学报(自然科学版)》 CAS CSCD 1996年第4期5-8,共4页
本文推广了环论中拟正则左理想的概念,引入τ-拟正则左理想的概念,给出环的相对于余遗传Torsiontheory的Jacobson根的元素刻划.
关键词 τ-小子模 τ-拟正则左理想 余遗传 torsion theory
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Tor-torsion pair与弱整体维数
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作者 邢建民 《纯粹数学与应用数学》 CSCD 2009年第3期563-565,共3页
利用torsion pair的方法讨论了Tor-torsion pair的一些性质,目的是找到Tor-torsion pair与环R的弱整体维数之间的关系,并得到了一个很好的不等式关系.
关键词 Tor—torsion PAIR 弱整体维数 平坦维数
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p-torsion模的性质
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作者 邢建民 李秀丽 《青岛科技大学学报(自然科学版)》 CAS 2010年第1期100-102,共3页
给出了p-torsion模的定义,并利用同调的方法讨论了p-torsion模的性质,目的是找到p-torsion模构成torsion类的条件以及构造p-torsionfree类,并最终找到了一个p-torsionfree类与投射维类的关系。
关键词 投射模 -torsion φ-torsion 预包络 完备环 局部环
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Influence of Microstructures and Textures on the Torsional Behavior of Pearlitic Wires 被引量:14
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作者 YandongLIU QiwuJIANG +3 位作者 GangWang YandongWANG A.Tidu LiangZUO 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第3期357-360,共4页
The microstructure, texture characteristics and torsion ability of two kinds of steel wires were investigated. The eutectoid steel wires were produced by hot and cold drawing with severe deformation. The torsinability... The microstructure, texture characteristics and torsion ability of two kinds of steel wires were investigated. The eutectoid steel wires were produced by hot and cold drawing with severe deformation. The torsinability of steel wires was measured under two cases, i.e. there exists either fiber texture or circular texture. The results showed that the torsional behavior of the steel wires was affected by their textures and microstructures. The {110}<110> circular texture weakened the torsion ability of the wires. The torsion fracture behavior of {110}<110> texture wires is related to the fact that only two slip systems were activated under simple shear strain deformation. 展开更多
关键词 Texture SLIP DRAWING torsion Microstructure
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