α_2相滑移系对γ-TiAl基多孪晶晶体屈服强度的影响  

Effect of α_2 lamellars slip systems on yield stress ofpolysynthetically twinning crystals for γ-TiAl

作　　者：苏继龙[1] 胡更开[2] 

机构地区：[1]福建农林大学机电工程系,福州350002 [2]北京理工大学应用力学系,北京100081

出　　处：《中国有色金属学报》2005年第10期1500-1505,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(10325210)

摘　　要：基于γ-基多孪晶晶体微结构及滑移系和形变孪晶空间晶体学位向分布的变形机制,提出了分析晶体屈服应力对外载轴和片层界面夹角间的依赖关系及影响因素的细观力学解析模型。分析了2α相中柱面和锥面上滑移系的启动对多孪晶晶体屈服应力的影响。模拟计算和分析结果表明:当θ=0°时,位错滑移方向跨越片层界面,2α相中柱面滑移系开动;当θ=45°时,滑移方向平行片层界面;当θ=90°方向时,γ相中与片层界面斜交的孪晶开动,而2α相中锥面滑移系由于其临界剪切应力(CRSS)很大而并不开动。多孪晶晶体中孪晶与普通位错、柱面与孪晶及锥面与柱面之间的CRSS比值关系可确定为k∶e∶z=1∶3∶18。An analytical micromechanical method, based on the lamellar microstructure, dislocation slip and twinning deformation mechanisms of polysynthetically twinned crystal （PST）, was proposed to investigate the yielding stress change as function of loading angle（θ） between the load axis and the lamellar boundaries and some influence paramelers for a PST crystal. The effects of prism and pyramidal slip systems in α2 lamellars on the yield stress of polysynthetically twin crystals of TiAI were analyzed. The simulation and analyses results indicate that, when θ= 0°, the slip is activited to cross the lamellar boundaries and the prism systems in α2 phase are activited. When θ= 45°, the slip occurs parallel to interlamellar boundaries. When θ=90°, the twinning in γ phase are actived to cross the lamellar boundaries and the pyramidal slip systems in α2 phase are not actived due to much higher critical resolved shear stress on the pyramidal planes. The rate of critical shear stress （CRSS） for twinning to ordinary slip, prism to twinning and pyramidal to prism can be described as k ： e ： z=1 ： 3 ： 18.

关 键 词：γ-基合金 多孪晶晶体 滑移系 屈服应力 细观力学 

分 类 号：TH142.2[一般工业技术—材料科学与工程]