延性金属层裂强度对温度、晶粒尺寸和加载应变率的依赖特性及其物理建模  

Dependence of spallstrength on temperature,grain size and strain rate in pure ductile metals

作　　者：张凤国[1] 赵福祺 刘军[1] 何安民[1] 王裴[1] Zhang Feng-Guo;Zhao Fu-Qi;Liu Jun;He An-Min;Wang Pei(Institute of Applied Physics and Computational Mathematics,Beijing 100088,China)

机构地区：[1]北京应用物理与计算数学研究所,北京100088

出　　处：《物理学报》2022年第3期185-192,共8页Acta Physica Sinica

基　　金：科学挑战专题(批准号:TZ2018001)资助的课题。

摘　　要：层裂强度表征了材料内部最大动态抗拉能力,并与材料本身的力学性质以及损伤早期演化相关.建立层裂强度计算的解析表达式,深入认识层裂强度所包含的微细观物理涵义,有利于更好地优化延性金属材料的层裂强度.目前大量的实验表明:延性金属材料的层裂强度对加载拉伸应变率、温度效应以及材料初始微细观结构具有很强的依赖关系.本文基于对孔洞成核与增长的损伤早期演化特性的分析,以及对温度效应和晶粒尺寸与材料本身力学性质之间关系的分析,给出了简单、实用的层裂强度的解析物理模型,物理模型的计算结果与典型延性金属高纯铝、铜和钽的层裂强度实验结果基本符合,从而验证了我们给出的层裂强度模型具有较好的适用性和预测性.When a shockwave,which can be generated by high velocity impact or explosive detonation,reflects from the free surface of a metal,it usually creates tensile stress inside the metal.While the tensile stress is large enough,voids nucleation,growth and coalescence happen inside the metal,causing the metal to spall.As one of the main contents of the spallation damage research,the spallation strength,which is often characterized by features of the free surface velocity history measured in spallation experiments,represents the maximum tensile stress that the material can withstand,and is actually a complex interaction among several competing mechanisms.Optimizing the spallation strengths of metals is important for their applications in the aerospace,automotive,and defense industries,and can be achieved by using the advanced manufacturing strategies,if we can know better the meaning and present analytic model of the spallation strength of metal.A large number of experiments show that the spallation strength of ductile metal is strongly dependent on the tensile strain rate,grain size and temperature of material.Based on the analysis of early spallation evolution and influence of grain size and temperature on the material,a simple analytic model of spallation strength is presented in this paper,which takes into account the effects of strain rate,grain size and temperature in materials.The applicability of this model is verified by comparing the calculated results from the model with the experimental results of spall strength of typical ductile metals such as high purity aluminum,copper,and tantalum.

关 键 词：层裂强度 孔洞成核与早期增长 晶粒尺寸 温度 拉伸应变率 延性材料 

分 类 号：O346[理学—固体力学] TG111[理学—力学]