细晶TiAl基合金的高温拉伸力学性能

TENSILE CHARACTERISTICS OF FINE GRAIN TiAl BASED ALLOY AT ELEVATED TEMPERATURE

研究了细晶粒Ｔｉ３３Ａｌ３Ｃｒ０５Ｍｏ（质量分数，％）合金的高温抗拉力学性能。研究结果表明，在９００℃下，全层片组织和双态组织的屈服强度分别为３８０ＭＰａ和２７８ＭＰａ，伸长率分别为９８０％和１１２０％，全层片组织表现出更好的高温综合力学性能。分析高温变形后合金的显微组织发现，高温变形时，除了γ晶粒中的位错滑移之外，还发现了层片间的相对滑动和层片弯曲等现象。此外，简要讨论了层片结构对高温力学性能的影响及高温变形机理。

Mechanical Properties of fine grain Ti 33Al 3Cr 0 5Mo(%) alloy were investigated at 900 ℃ through tensile tests. It was found that, when the grains were refined to ～10 μm, the specimens with full lamellar and duplex microstructure reached the yield strength of 380 MPa and 278 MPa respectively, while the relative elongations of the two kinds of specimens were almost the same, that is, 98% and 112% respectively. The microstructural analysis of the deformed specimens with electron microscopy showed that there were a lot of dislocation slip in gamma grains, as well as remarkable lath sliding along the interface of the lamellar structure and lath bending in lamellar colonies. In addition, the effect of the lamellar structure on the tensile properties and the mechanism of deformation of TiAl at elevated temperature were briefly discussed.