面心立方金属平面变形的屈服应力状态分析

Analysis of yield stress states of fcc metals under plane deformation

将fcc金属滑移和孪生 2种机制综合起来进行考虑 ,应用Bishop Hill最大功原理 ,计算和分析了临界剪切应力之比 ζ不同时各理想取向平面共生变形时的屈服应力状态、相应活化系及Taylor因子M .结果表明 :当 ζ >1 /3时 ,随着 ζ的减小 ,C ,G ,RCu3种取向时的M值不变 ,共同的活化系均为滑移系 ,不易孪生 ;其它取向的M值越来越小 ,共同的活化系均包括滑移系和孪生系 ,具有孪生倾向 .ξ取不同值时 ,最强和最弱的M值的取向位置均没有改变 ,分别位于RG 取向处和C ,G取向处 .

The Bishop Hill maximum principle is applied to fcc metals for twinning and slip under plane deformation. The yield stress states, corresponding active systems and Taylor factors M for main ideal orientations have been calculated and analyzed when the ratios of critical shear stresses are different. The results show that when ζ >1/3, for C, G, R C u orientations, the M values remain unchanged as ζ decreases and twinning is difficult since all common active systems are slip systems; for the other orientations, the M values become less and less and the common active systems include slip and twinning systems, which have the trend of twinning. When ζ varies, the orientations for the strongest and weakest M do not change, they are located in R G and C, G orientations respectively. [