检索结果-南通市图书馆

Journal of Materials Science & Technology 2023年第12期143卷 242-252页

作者： H.T.Jeong W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul121-791Republic of Korea

The activation volume(V∗)and strain-rate sensitivity exponent(m)of CoCrFeMnNi and Al_(0.5)CoCrFeMnNi high entropy alloys(HEAs)with various grain sizes(ranging between 2.4 and 356μm)were measured at different strain rates and strain levels at room *** the strain rate decreased,the plastic strain decreased,and the grain size increased,V∗*** enhanced solid-solution strengthening by addition of aluminum decreased V∗.The Hassen plot was modified to capture the grain-size depen-dence of V∗by considering the grain-size dependence of the dislocation *** the plastic strain increased,the strain rate decreased,and the grain size decreased,m *** behavior of m could be quantitatively predicted by using equations derived for the grain-size-dependent V∗and flow *** difference in the grain-size dependence of m between conventional face centered cubic(FCC)metals and FCC HEAs over the nanograin size range could not be explained in terms of a relatively large Hall-Petch slope of the FCC HEAs compared with that of the FCC conventional metals,but was explainable in terms of a substantially higher probability of activation of grain-boundary diffusion-controlled grain-boundary-sliding mechanism at nanograin sizes in the FCC conventional metals than in the FCC HEAs.

关键词： Grain size High entropy alloys Activation volume strain-rate sensitivity Solid solution

rate-dependent mechanical behavior of single-,bi-,twinned-,and poly-crystals of CoCrFeNi high-entropy alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第25期120卷 253-264页

作者： Siyuan Wei Yakai Zhao Jae-il Jang Upadrasta Ramamurty School of Mechanical and Aerospace Engineering Nanyang Technological University639798Republic of Singapore Division of Materials Science and Engineering Hanyang UniversitySeoul 04763Republic of Korea Technology and Research Institute of Materials Research and EngineeringAgency for Science138634Republic of Singapore

While considerable effort is made to understand the solid solution strengthening on the deformation behavior of high-entropy alloys(HEAs),relatively little attention is paid to the role of microstructural interfaces,especially twin boundaries(TBs),on the strain-rate sensitivity(SRS)of *** address this,we have conducted micropillar compression experiments on single-,bi-,and twinned-crystals of Co CrFe Ni HEA and compared the results with those obtained with uniaxial tensile and compression tests on polycrystalline bulk *** show that SRS,as well as the yield strength and plastic flow behavior,in single crystals are orientation dependent due to the differences in the maximum Schmid *** the high-angle grain boundaries arrest dislocation motion,TBs allow for dislocation transmission through them,which result in distinct mechanical *** the bi-crystal’s deformation behavior is controlled by the‘hard’grain,twinned crystals exhibit an‘averaged’*** large diversity of the reported SRS values in face centered cubic HEAs could be due to the varying fractions and thus contributions of annealing twins in the tested samples.

关键词： High-entropy alloy strain-rate sensitivity Micropillar compression Orientation Nanoindentation

Superplasticity-like creep behavior of coarse grained ternary Al alloys

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2010年第4期20卷 564-571页

作者：乔军 E.M.TALEFF College of Materials Science and Engineering University of Science and Technology Liaoning Department of Mechanical Engineering University of Texas at Austin

Enhanced tensile ductilities in coarse grained Al-Mg-Zn and Al-Mg-Fe materials were *** materials were Al-2Mg-5Zn,Al-3Mg-5Zn,Al-4Mg-5Zn,Al-3Mg-0.11Fe,Al-3Mg-0.27Fe,and *** elongation-to-failure tests were conducted at constant cross-head speed and constant temperatures from 300 to 450℃.strain rate change tests were conducted at a constant temperature from 300 to 450℃and in strain-rate range from 4.31×10-5to 1.97×*** results show that over 100%ductilities are consistently achieved in these *** superplasticity-like behavior is rate-controlled by solute-drag *** ternary Zn and Fe additions do not have an adverse effect on solute-drag creep and ductility,they increase stress exponent and its sensitivity to Mg content during solute-drag creep.

关键词： Al-Mg alloys superplasticity solute-drag creep tensile ductility strain-rate sensitivity

A QUASI-FLOW CONSTITUTIVE MODEL WITH strain-rate DEPENDENCE

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2004年第3期20卷 283-291页

作者：胡平申国哲杨光 State Key Lab.of Automotive Dynamic Simulation Institute of Automobile Body Manufacturing EngineeringChangchun 130025China College of Mathematics in Jilin University Changchun 130025China

In this paper,the proposed is a quasi-flow constitutive model with strain-rate sen- sitivity for elastic plastic large *** model is based on the Quasi-flow Corner theory, and is suitable for the sheet metal forming process simulation with a variable punch machine velocity. Uniaxial tensile tests and deep-drawing tests of a circular blank with square punch are carried out and numerically *** consistency between the experimental and the numerically simulated results shows the validity of the present new constitutive model.

关键词： strain-rate sensitivity quasi-flow constitutive model sheet metal forming

Material embrittlement in high strain-rate loading

在线全文

学校读者我要写书评

暂无评论

International Journal of Extreme Manufacturing 2019年第2期1卷 53-71页

作者： Xiuxuan Yang Bi Zhang Dalian University of Technology DalianPeople’s Republic of China The Southern University of Science and Technology ShenzhenPeople’s Republic of China The University of Connecticut StorrsCTUnited States of America

Material embrittlement is often encountered in machining,heat treatment,hydrogen and lowtemperature conditions among which machining is strain-rate *** strain-rate evoked embrittlement is expected in material loading processes,such as in high-speed machining and projectile *** order to understand the fundamental mechanisms of the strain-rate evoked material embrittlement,this study is concerned with the material responses to loading at high *** then explores the strain-rate evoked material embrittlement and fragmentation during high strain-rate loading processes and evaluates various empirical and physical models from different researchers for the assessment of the material *** study proposes strain-rate sensitivity for the characterization of material embrittlement and the concept of the pseudo embrittlement for material responses to very high strain-rates.A discussion section is arranged to explore the underlying mechanisms of the strain-rate evoked material embrittlement and fragmentation based on dislocation kinetics.

关键词： embrittlement strain rate strain-rate sensitivity dislocation

Viscoplastic Damage-Softening Constitutive Model for Concrete Subjected to Uniaxial Dynamic Compression

在线全文

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2017年第4期26卷 427-433页

作者： Xiaowang Sun Yongchi Li Ruiyuan Huang Zhongbao Ye Kai Zhao Department of Modern Mechanics University of Science and Technology of ChinaHefei 230026China

A new viscoplastic damage-softening constitutive model is presented. It is developed by integrating a Bodner-Partom viscoplastic model with a newdamage evolution equation. A set of ordinary differential equations（ ODEs） is formulated,and a Runge-Kutta integral method is used to get stress-strain curves given by the model. Also,stress-strain curves of a wide range of strain-rates for concrete were obtained by split Hopkinson pressure bar（ SHPB） tests. By fitting the integral stressstrain curves to the experimental ones with the least square optimization method,we determined the material parameters in our model. Some properties of the newmodel,such as strain-rate sensitivity,damage evolution characteristics,strain-rate jump effects and unloading feature,are *** results showthat our new model can describe dynamic behaviors of concrete very well,and our integrating-fitting-optimizing method to get material parameters is valid.

关键词： constitutive model damage evolution strain-rate sensitivity dynamic behavior of concrete

Microstructure-Property Relationship of High Strength Low Alloy Steels During Tensile Testing at High strain rates

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2011年第S1期18卷 869-873页

作者： Moss Matthew Timokhina Ilana Hodgson Peter Institute for Technology Research and Innovation Deakin UniversityGeelongVictoria3217Australia

The influence of strain-rate on the room temperature mechanical properties of Dual-Phase and Transformation Induced Plasticity (TRIP) steels was *** results showed that both plastic strain,and strength properties increased with increasing strain rates at high strain *** strain rates lower than approximateil 1s-1 the properties no longer have an advantageous proportionality to strain rate and remain strain rate *** explanations are offered for trends exhibited,in terms of thermal and athermal considerations,in relation to the respective microstructures of the two steels.

关键词： TRIP dual-phase steel high strain rate microstructure strain-rate sensitivity