An index for deformation controllability of small-volume materials  

作　　者：WANG ZhangJie SHAN ZhiWei LI Ju SUN Jun MA Evan 

机构地区：[1]Center for Advancing Materials Performance from the Nanoscale CAMP-Nano) & Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University [2]Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology [3]Department of Materials Science and Engineering, Johns Hopkins University

出　　处：《Science China(Technological Sciences)》2014年第4期663-670,共8页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.50925104,11132006,51231005 and 51321003);the National Basic Research Program of China("973"Program)(Grant Nos.2010CB631003 and 2012CB619402);the support from the"111"Project of China(Grant No.B06025);JL also acknowledges the support by US National Science Foundation(Grant Nos.DMR-1240933 and DMR-1120901)

摘　　要：Mechanical tests on small-volume materials show that in addition to the usual attributes of strength and ductility, the controlla- bility of deformation would be crucial for the purpose of precise plastic shaping. In our present work, a ＂mechanical controlla- bility index＂ （MCI） has been proposed to assess the controllability of mechanical deformation quantitatively. The index allows quantitative evaluation of the relative fraction of the controllable plastic strain out of the total strain. MCI=0 means completely uncontrollable plastic deformation, MCI=∞ means perfectly controllable plastic shaping. The application of the index is demonstrated here by comparing two example cases： 0.273 to 0.429 for single crystal A1 nanopillars that exhibit obvious strain bursts, versus 3.17 to 4.2 for polycrystalline A1 nanopillars of similar size for which the stress-strain curve is smoother.

关 键 词：mechanical controllability index plastic deformation strain bursts nanomechanics 

分 类 号：TB302[一般工业技术—材料科学与工程]