以细观力学法确定γ-TiAl基PST晶体宏观屈服准则  

Applying micromechanical method to characterize the yield criterion for polysynthetically twinning crystals of TiAl

作　　者：苏继龙[1] 

机构地区：[1]福建农林大学机电工程学院,福州350002

出　　处：《中国农业大学学报》2005年第5期76-80,共5页Journal of China Agricultural University

摘　　要：基于γ-TiAl基PST晶体的微结构及滑移系和形变孪晶的空间晶体学位向分布的变形机制,提出分析PST晶体宏观屈服准则的细观力学解析模型。从γ-TiAl基PST晶体微结构复合材料代表单元的应力和应变场出发,对双轴载荷下PST晶体微观结构的宏观屈服面进行数值模拟,结合塑性理论中Hill屈服准则,得到γ-TiAl基PST晶体的宏观屈服准则方程。结果表明:PST晶体屈服应力σy和外载轴与片层微结构界面之间的夹角θ存在强烈依赖关系;PST晶体在拉伸和压缩时屈服应力差别很小。An analytical mJcromechanical method was proposed to investigate the yield criterion for a PST crystal based on lamellar microstructure and dislocation slip and twinning deformation mechanisms of polysynthetically twinned （PST） crystal. The emphasis was put upon simulating the yield surface of γ-TiAl based PST crystal under biaxial loading on the basis of calculating stress and strain of lamellar microstructure of PST. With the Hill theory, the yield criterion function of γ-TiAl based PST crystal was obtained. The results demonstrated that yielding stress of PST crystal depends strongly on loading angle between microstructure boundaries and differs only slightly with tension and compression applied loading conditions.

关 键 词：γ-Ti~基合金 PST晶体 屈服准则 细观力学 

分 类 号：TH142.2[一般工业技术—材料科学与工程]