α2相滑移系对全片层组织TiAl合金屈服应力影响的初步分析

摘要:

基于PST晶体的微结构和γ相及α2相普通位错和孪晶滑移启动，结合细观力学方法，通过数值模拟两相中的各滑移系上的分切应力，得出PST晶体屈服应力和外加载荷与片层之间夹角θ的关系。重点分析了α2相中柱面滑移系的启动对PST晶体屈服应力大小变化的影响。α2相中柱面滑移系的启动对PST晶体小加载角方向的屈服应力有比较明显的影响。所采用的细观方法和得到的结论对进一步研究全片层TiAl合金的屈服强度有一定的参考价值。

Abstract:

Micromechanics theory is used to analyze the yield stress of polysynthetically twinning (PST) crystals of ?TiAl as a function of the loading angle between the lamellar and the loading axis. The numerical results of yield strength, based on considering the lamellar microstructure and the deformation mechanisms such as ordinary slip systems and true twinnings in PST crystals composed of and phase, is obtained by using calculating of resolved shear stresses in all slip systems based on micromechanical method. The emphasis was put on discussing the influence of prism slip systems in ? phase on the yield stress of polysynthetically twinning (PST) crystals of ?TiAl. The results indicates that the slip systems in ? phase have, to a certain extent, influences on the yield strength of PST crystals, especially at small angles ?directions.