首页 | 本学科首页   官方微博 | 高级检索  
     检索      

孪晶对Be材料冲击加-卸载动力学影响的数值模拟研究
引用本文:潘昊,王升涛,吴子辉,胡晓棉.孪晶对Be材料冲击加-卸载动力学影响的数值模拟研究[J].物理学报,2018,67(16):164601-164601.
作者姓名:潘昊  王升涛  吴子辉  胡晓棉
作者单位:北京应用物理与计算数学研究所, 北京 100094
基金项目:科学挑战专题(批准号:TZ2018001)和国家自然科学基金(批准号:11702031)资助的课题.
摘    要:在高压、高应变率加载条件下,孪晶变形对材料的塑性变形具有重要的贡献,而目前孪晶对金属材料的动态屈服强度、冲击响应等的影响还没有被充分揭示.为此,本文考虑孪晶变形和晶粒碎化,针对铍(Be)材料在高应变率加载下的动态力学响应发展了含孪晶的热弹-黏塑性晶体塑性模型.经过和实验结果的对比,发现该模型可以更准确地预测Be材料在动态加载下,尤其是高压动态加载下的屈服强度.进一步,基于该塑性模型研究了Be材料在冲击加载下的准弹性卸载行为,结果表明剪切波速随着压力和剪应变的变化而发生变化是材料产生准弹性卸载现象的主要原因.此外,研究了冲击波卸载过程中Be材料孪晶的演化过程,发现Be材料卸载过程中也伴随着孪晶的产生.

关 键 词:孪晶  晶粒碎化  晶体塑性模型  冲击加载
收稿时间:2018-03-15

Effect of twining on dynamic behaviors of beryllium materials under impact loading and unloading
Pan Hao,Wang Sheng-Tao,Wu Zi-Hui,Hu Xiao-Mian.Effect of twining on dynamic behaviors of beryllium materials under impact loading and unloading[J].Acta Physica Sinica,2018,67(16):164601-164601.
Authors:Pan Hao  Wang Sheng-Tao  Wu Zi-Hui  Hu Xiao-Mian
Institution:Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
Abstract:As a rare metal material with low density, high strength and high melting point, beryllium (Be) is widely utilized in many fields including aerospace and vehicles. Dynamic loadings such as impact and high-rate compression often happen in the applications of Be materials in these fields. However, the dynamic behaviors of Be materials under high pressure and high-rate loading have not been fully investigated, although they are valuable for better applications of Be materials. articularly, the effect of twinning on dynamic behaviors of Be material is very important for better understanding the plasticity deformation mechanism of Be material. In this paper, a thermoelastic-viscoplastic crystal plasticity model is developed for dynamic behaviors of Be material under high pressure and high strain-rate loading based on the physical mechanism of plasticity deformation. Besides, the dislocation motion and work hardening are considered within the constitutive framework by the Orowan relation and the Taylor equation respectively, and the contribution of twinning to the plasticity deformation is also considered via twinning fraction evolution and fragmentation of crystal due to twinning deformation. With the model, dynamic behaviors of Be material are investigated, including effect of pressure on the dynamic yield strength, the quasi-elastic unloading behavior, and evolution of twinning in shock loading and unloading. Compared with the classical SG model, the model developed in this paper accords better with the experimental results in predicting yield strength of Be material under impact loading, especially with high pressure. Moreover, it is revealed that the condition of yield strength of the Be material is divided into three cases, namely the non-twinning under low pressure, the twinning deformation under moderate pressure, and the twinning fragmentation under high pressure. The unloading behavior of Be material under impact loading is also studied with the model, and the quasi-elastic unloading behavior observed in experiments many times, is faithfully predicted. It is found that the quasi-elastic unloading phenomenon of the material is closely related to the variation of the shear velocity of shock wave with the shear strain, which suggests that the non-linear elastic property of the material is an important reason for this phenomenon. Finally, the evolution of twinning of Be material in the shock loading is studied, showing that the increasing of twinning friction happens not only in the loading process but also in the unloading process of the shock waves. Some crystals break up into sub-crystals due to the fact that the volume fraction of twinning exceeds the critical fraction in the evolution of twinning.
Keywords:twinning  crystal fragmentation  crystal plasticity model  impact loading
本文献已被 CNKI 等数据库收录!
点击此处可从《物理学报》浏览原始摘要信息
点击此处可从《物理学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号