Stability of lamellar microstructure of hard orientated PST crystal of TiAl alloy
Stability of lamellar microstructure of hard orientated PST crystal of TiAl alloy
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DOI：
10.1016/s1359-6454(03)00012-0
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发表时间：
2003-05
期刊：
影响因子：
9.4
通讯作者：
H. Y. Kim;K. Maruyama
中科院分区：
文献类型：
--
作者：
H. Y. Kim;K. Maruyama
定量研究了平行于压缩轴取向的硬取向Ti-48 Al PST晶体在蠕变过程中的显微组织变化。γ层的六种取向变体以相似的比例存在，但在生长的PST晶体中最常见的γ/γ界面是真正的孪晶型。蠕变变形后，由于γ/γ界面的消除，层片发生粗化。120°旋转和假孪晶界面的比例减少，而真孪晶界面的比例增加。与孪晶有关的γ/γ界面通过台阶的形成和移动而迁移，通过边缘迁移而消失。120°旋转界面发生明显的隆起和迁移，形成等轴晶。在蠕变变形过程中，α2/γ界面比γ/γ界面更稳定。假孪晶和120°旋转断层界面的热稳定性低于真孪晶界面。
Microstructural changes were investigated quantitatively during the creep deformation of a hard oriented Ti-48Al PST crystal with the lamella plates oriented parallel to the compression axis. Six orientation variants of the γ lamellae were present in similar proportions, but the most frequently observed γ/γ interface was of the true twin-type in the as-grown PST crystal. After creep deformation, the lamellae coarsened by the elimination of the γ/γ interfaces. The fraction of 120°rotational and pseudo-twin interfaces decreased, while that of true twin interfaces increased. The twin-related γ/γ interfaces migrated by ledge formation and its movement, and the interfaces disappeared by edge migration. The 120° rotational interfaces bulged and migrated substantially, and formed equiaxed grains. The α2/γ interface was more stable than the γ/γ interface during creep deformation. Pseudo-twin and 120°rotational fault interfaces were less thermally stable than the true twin interface.