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高应变率下的扩散型相变:绝热剪切形变过程中铝合金沉淀相的瞬间溶解

发表时间:2014-05-15  浏览量:1666  下载量:501
全部作者: 杨扬,罗淑洪,陈培显,胡海波,汤铁钢,张庆明,张晓伟
作者单位: 中南大学材料科学与工程学院;中国工程物理研究院流体物理研究所;北京理工大学爆炸科学与技术国家重点实验室
摘 要: 采用分离式霍普金森压杆(split Hopkinson pressure bar, SHPB)对2195-T6态铝锂合金帽型试样进行动态加载,利用光学显微镜(optical microscopy,OM)和透射电子显微镜(transmission electron microscopy,TEM)研究动态剪切变形区的微观结构变化。结果表明:在绝热剪切变形后绝热剪切带(adiabatic shear band,ASB)内晶粒急剧细化形成纳米等轴晶,并发现在高应变速率的绝热剪切过程中发生了扩散型相变——加载前基体中的沉淀相瞬间溶解于基体。首次探讨了绝热剪切形变过程中沉淀相瞬间溶解的热力学和动力学,并建立了沉淀相的溶解模型,即伴随着扩散的挠动模型。
关 键 词: 材料科学基础学科;2195铝锂合金;绝热剪切变形;沉淀相瞬间溶解
Title: Diffusive transformation at high strain rate: instant dissolution of precipitates in aluminum alloy during adiabatic shearing deformation
Author: YANG Yang, LUO Shuhong, CHEN Peixian, HU Haibo, TANG Tiegang, ZHANG Qingming, ZHANG Xiaowei
Organization: School of Materials Science and Engineering, Central South University; Institute of Fluid Physics, Chinese Academy of Engineering Physics; State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology
Abstract: Dynamic testing of 2195-T6 aluminum lithium alloy was carried out in a hat-shaped specimen by a split Hopkinson pressure bar (SHPB) at ambient temperature. The microstructure and phase transformation in dynamic shear deformation band produced in 2195-T6 aluminum lithium alloy were investigated by means of optical microscopy (OM) and transmission electron microscopy (TEM). The results showed that the fine equiaxed grains were formed in adiabatic shear band (ASB), and the diffusive transformation took place during adiabatic shearing deformation, namely the precipitates existed in the matrix of aluminum alloy before loading were instantly dissolved into matrix. The thermodynamics and kinetics of instantaneous dissolution of the precipitates during adiabatic shearing were firstly investigated, and a dissolution model considering the factor of perturbation was established in the present work.
Key words: basic subject of material science; 2195 aluminum lithium alloy; adiabatic shearing deformation; instant dissolution of precipitates
发表期数: 2014年5月第9期
引用格式: 杨扬,罗淑洪,陈培显,等. 高应变率下的扩散型相变:绝热剪切形变过程中铝合金沉淀相的瞬间溶解[J]. 中国科技论文在线精品论文,2014,7(9):897-907.
 
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