γ-TiAl合金全片层组织室温变形协调行为

Compatibility of deformation in fully lamellar microstructure of γ -TiAl alloy at ambient temperature

研究Ti-47.5Al-2Cr-2Nb-0.2B全片层组织室温变形结构中γ/γ片层间变形协调行为。引入多晶体塑性变形的几何协调因子m,并利用矩阵分析方法计算120°旋转有序型、真孪晶型和伪孪晶型γ/γ界面两侧片层中各种滑移系之间的m值,与实验结果比较发现,通过计算m值可以预测不同类型γ/γ界面两侧片层中的有效滑移系,120°旋转有序型γ/γ界面几何协调性最好,1/6<1 12]{111}形变孪晶可以通过1/2<1 10]{111}普通位错协调变形;对于真孪晶型界面,1/6<1 12]{111}形变孪晶可以扩展通过,并仍以1/6<1 12]{111}孪晶变形进行协调。

The compatibility of deformation in fully lamellar microstructure of Ti-47.5Al-2Cr-2Nb-0.2B alloy at room temperature was studied. A geometric compatibility factor m was calculated by matrix operation to compare the compatibility between two slip systems in two neighboring γ, lamellae with 120°-rotational, true-twin and pseudo-twin relationships. The experimental results show that the effective slip systems between two neighboring γ, lamellae can be predicted by calculation of the m values. Among the three type γ/γ, interfaces, the compatibility between 120°-rotational ordered interface is the best, the deformation of 1/6（112] {111} twinning in one γ, lamella can transfer into another γ, lamella by 1/2（110] {111} ordinary dislocation slip. For true-twin interface, 1/6（112] {111} twin can propagate into a neighboring γ, lamella through 1/6 （112] {111} twinning.