Mesoscopic superelasticity,superplasticity,and superrigidity  

作　　者：MA ZengSheng ZHOU ZhaoFeng HUANG YongLi ZHOU YiChun SUN ChangQing 

机构地区：[1]Key Laboratory of Low-dimensional Materials andApplication Technology,Ministry of Education,and Faculty of Materials,Optoelectronics and Physics,Xiangtan University,Xiangtan 411105,China [2]School of Electric and Electronic Engineering,Nanyang Technological University,Singapore 639798,Singapore

出　　处：《Science China(Physics,Mechanics & Astronomy)》2012年第6期963-979,共17页中国科学：物理学、力学、天文学（英文版）

基　　金：supports from the National Natural Science Foundation of China(Grant Nos. 11002121,11102176 and 11172254)

摘　　要：Atomic-undercoordination-induced local bond contraction,bond strength gain,and the associated temperature (T)-dependent atomic-cohesive-energy and binding-energy-density are shown to originate intrinsically the exotic paradox of superplasticity,superelasticity,and superrigidity demonstrated by solid sizing from monatomic chain to mesoscopic grain.The paradox follows these relationships:(ε(K,T)y(K,T)σ(K,T))∝(exp(B/△T_(mk)),(η_1△T_(mk))d～(-3),[1+AK～(-2/2)exp(△T_(mk)/T)]△T_(mk)d～(-3)),(Plastic strain)(Elastic modulus)(Yield stress,IHPR)where A,B,η1,d and△T_(mk)=Tm(K) Tare size (K)-dependent physical parameters.Tm (K) is the melting point.Mechanical work hardening during compressing and self-heating during stretching modulate the measured outcome extrinsically.Superplasticity dominates in the solid-quasimolten-liquid transition state.The competition between the accumulation and annihilation of dislocations activates the inverse Hall-Petch relationship.Therefore,it is essential for one to discriminate the intrinsic competition between the local bond energy density gain and the atomic cohesive energy loss from the extrinsic factors of pressure and temperature in dealing with atomistic mechano-thermo dynamics.Atomic-undercoordination-induced local bond contraction,bond strength gain,and the associated temperature （T）-dependent atomic-cohesive-energy and binding-energy-density are shown to originate intrinsically the exotic paradox of superplasticity,superelasticity,and superrigidity demonstrated by solid sizing from monatomic chain to mesoscopic grain.The paradox follows these relationships：（ε（K,T）y（K,T）σ（K,T））∝（exp（B/△T_（mk））,（η_1△T_（mk））d～（-3）,[1＋AK～（-2/2）exp（△T_（mk）/T）]△T_（mk）d～（-3））,（Plastic strain）（Elastic modulus）（Yield stress,IHPR）where A,B,η1,d and△T_（mk）=Tm（K） Tare size （K）-dependent physical parameters.Tm （K） is the melting point.Mechanical work hardening during compressing and self-heating during stretching modulate the measured outcome extrinsically.Superplasticity dominates in the solid-quasimolten-liquid transition state.The competition between the accumulation and annihilation of dislocations activates the inverse Hall-Petch relationship.Therefore,it is essential for one to discriminate the intrinsic competition between the local bond energy density gain and the atomic cohesive energy loss from the extrinsic factors of pressure and temperature in dealing with atomistic mechano-thermo dynamics.

关 键 词：BOLS theory LBA approach atomistic mechano-thermo dynamics elastic modulus yield strength temperature coordination bond stress 

分 类 号：O413.1[理学—理论物理] TG146.21[理学—物理]