一、引言 钛合金铸态组织由魏氏α与粗大的晶界α所组成,因而其室温塑性低,疲劳强度差。由于钛合金的魏氏组织有很强的遗传性,很难单纯利用热处理方法加以改善,因此使用受到限制。使铸造钛合金获得细小等轴晶粒的传统方法是进行大变形量加工以及相应的热处理。近年来,较系统地研究了一种用单 I. INTRODUCTION The as-cast microstructure of titanium alloy consists of Wei’s α and coarse grain boundary α, so its low plasticity at room temperature and poor fatigue strength. Due to the strong inheritance of the Widman’s tissue of titanium alloy, it is difficult to simply improve the heat treatment method, so the use is limited. The traditional method of obtaining fine equiaxed grains of a cast titanium alloy is to carry out a large deformation amount processing and a corresponding heat treatment. In recent years, a more systematic study of a single