文献类型：期刊文献

英文题名：Fifth-degree elastic energy for predictive continuum stress-strain relations and elastic instabilities under large strain and complex loading in silicon

作者：Chen, Hao[1];Zarkevich, Nikolai A.[2];Levitas, Valery I.[2,3,4];Johnson, Duane D.[2,5];Zhang, Xiancheng[1]

机构：[1]East China Univ Sci & Technol, Key Lab Pressure Syst & Safety, Minist Educ, Sch Mech & Power Engn, Shanghai 200237, Peoples R China;[2]Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA;[3]Iowa State Univ, Dept Aerosp Engn, Ames, IA 50011 USA;[4]Iowa State Univ, Dept Mech Engn, Ames, IA 50011 USA;[5]Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA

年份：2020

卷号：6

期号：1

外文期刊名：NPJ COMPUTATIONAL MATERIALS

收录：;EI(收录号：20203209020657);WOS:【SCI-EXPANDED(收录号:WOS:000555977000001)】；

基金：V.I.L. and H.C. are supported by NSF (CMMI-1943710 & MMN-1904830), ONR (N00014-16-1-2079), & XSEDE (MSS170015). N.A.Z. and D.D.J. are supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science & Engineering Division. Ames Laboratory is operated for DOE by Iowa State University under contract DE-AC02-07CH11358. X.C.Z. and H.C. are also sponsored by the National Key Research and Development Program of China (2018YFC1902404), the National Natural Science Foundation of China (51725503, 51975211), and Innovation Program of Shanghai Municipal Education Commission (2019-01-07-00-02-E00068).

语种：英文

外文关键词：Strain - Lagrange multipliers - Silicon compounds - Loading - Twinning - Elasticity - Phase transitions

摘要：Materials under complex loading develop large strains and often phase transformation via an elastic instability, as observed in both simple and complex systems. Here, we represent a material (exemplified for Si I) under large Lagrangian strains within a continuum description by a 5(th)-order elastic energy found by minimizing error relative to density functional theory (DFT) results. The Cauchy stress-Lagrangian strain curves for arbitrary complex loadings are in excellent correspondence with DFT results, including the elastic instability driving the Si I -> II phase transformation (PT) and the shear instabilities. PT conditions for Si I -> II under action of cubic axial stresses are linear in Cauchy stresses in agreement with DFT predictions. Such continuum elastic energy permits study of elastic instabilities and orientational dependence leading to different PTs, slip, twinning, or fracture, providing a fundamental basis for continuum physics simulations of crystal behavior under extreme loading.