不同失稳判据下喷射沉积超高强铝合金热变形失稳区域分布及演变特点

Distribution and evolution characteristics of thermal deformation instability regions for spray deposited ultra high strength aluminum alloy based on various instability criteria

基于热模拟试验获得超高强铝合金真应力-真应变数据的基础上,采用Prasad、murty、Gegel和Malas失稳准则分别构建不同真应变下的试验合金失稳图,并分析不同失稳准的失稳区域分布及演变特点。结果表明:所有判据下的失稳图中,高温高应变速率区域是失稳区高频出现区域;随着真应变增大,呈大面积离散状分布的Prasad失稳区域不断减小;呈离散状分布的murty判据下的失稳区域,在中高温和中应变速率区域产生新的失稳区域,区域范围呈增大趋势;随着真应变增大,Gegel和Malas判据下失稳区域分布及演变特点相似,低温低应变速率下的失稳区域均呈增大趋势,中高温高应变速率区域对应的失稳区域逐渐呈减小趋势。

Based on the acquired true stress-true strain data of ultra high strength aluminum by thermal simulation, the four instability criteria of Prasad, Murty, Gegel and Malas were used to establish the instability maps under d＇ifferent true strain. Distribution and evolution characteristics of thermal deformation instability re^ions were studied. The results show that instability domains are located at higher strain rate and higher temperature regions. As the true strain increases, the instability domains with discrete distribution in large area become smaller by Prasad criteria. By Murty, the instability regions are distributed under the discrete state. A new instability region creates at middle higher temperature and strain rate and becomes larger. As the true strain increases, the distribution and evolution characteristics of instability regions by Gegel and Malas are similar. The areas of instability regions show an increase tendency at lower temperature and lower strain rate and show a decrease tendency at middle higher temperature and higher strain rate doniains.