固溶处理对Ti60合金组织及拉伸性能的影响

Influence of solution treatment on the microstructure and mechanical property of Ti60 alloy

摘要:

本文通过对600°C用Ti60高温钛合金在不同温度固溶热处理，获得α′单相和α+α′两相组织，对比了两种组织特征及室温、300℃和600℃下的拉伸性能，探讨了初生α相对力学性能的影响规律。结果表明淬火过程中β相只析出α′马氏体相，α+α′组织保留约10%初生α相，初生α相的存在引起马氏体组织抗拉强度降低和塑性提升，进而获得更加匹配的强度和塑性。其中α+α′组织韧窝尺寸较大，因为少量初生α相则能够细化β晶粒尺寸，通过增加晶界面积阻碍裂纹扩展，进而提高塑性，随着温度升高，初生α相对合金塑性影响逐步减小。

Abstract:

Both of the α′ and α+α′ martensite microstructures of Ti60 alloy as high temperature titanium alloy used up to 600°C can be obtained by solution treatments at different temperatures. The morphologies of the two microsturctures are compared as well as the tensile properties at room temperature, 300°C and 600°C. The results indicate that all the β phase transforms to α′ phase during quenching, and only about 10% primary α phase retains in the α+α′ microstructure. The little decrease of strength and great increase of ductility can be attributed to the partial solution of primary α phase. The size of dimple observed on the fracture of specimens with α+α′ microstructure at room temperature is larger than that with α′ microstructure. Because the retained primary α phase dedicates to the refinement of β grains, leading to the disturbance of expansion of cracks by increasing the length of grain boundaries. The influence of the primary α phase on the tensile properties decreases with the increasing of the tensile temperature.