TiAl基两相合金热形变诱导形成T(Q)型孪晶与α_2薄片的TEM研究

HOT DEFORMATION INDUCED T(Q) TWIN AND α 2(Q) LATHS IN α TiAl BASED TWO PHASE ALLOY

利用常规和高分辨电镜（ＨＲＥＭ），研究了热形变诱导的Ｔｉ４５Ａｌ８Ｎｂ２．５Ｍｎ０．０５Ｂ合金中偏离严格取向关系的α２／γ片层界面结构，以及横过片层的Ｔ（Ｑ）型γ孪晶与α２（Ｑ）薄层优先在这些偏离严格取向关系的α２／γ片层界面上形成的机理。由于其片层界面上较大的应力集中，通过界面上的复杂位错核心反应将导致这些Ｔ（Ｑ）型γ孪晶与α２（Ｑ）薄层的产生。

The interfacial structure of α 2/ γ lamellae deviating the strict orientation relationship in a hot forged Ti 45Al 10Nb 2.5Mn 0.05B(mole fraction, %) alloy and the preferential formation mechanism of T(Q) type twin and α 2(Q) laths at these interlamellar interfaces have been investigated by the conventional and high resolution electron microscopy. The lath formation process involves complex transformations of the interfacial dislocation core and can be activated preferentially under concentrated stress fields at these interlamellar interfaces.