【摘要】 经验证明均匀的细晶粒双态复相组织γ TiAl基合金具有较好的加工性能 ,常用的获得这种组织的热处理工艺是通过在α+γ相区循环热处理获得的。但是以往的循环热处理工艺具有难控制 ,易出现裂纹 ,不能广泛应用于工业生产的缺陷。本文采用风冷循环热处理工艺 ,解决了这些问题 ,获得了晶粒直径为 2 0 μm左右的复相双态TiAl合金 ,并研究了循环热处理过程中的显微组织演化。结果表明 :随着循环次数的增加 ,材料的均匀性和等轴性有较大的改观。通过改变循环热处理温度以及时间 ,还可以获得含有不同体积分数片层晶粒的双态组织更多还原

【Abstract】 It is well known that uniform fine grain duplex γ TiAl alloy has good comprehensive properties.Fein full lamellar (FFL) microstructure could be obtained by the method of circle heat treatment in (α+γ)phase field.But its difficulty in controlling and tendency to form cracks has impeded its wide industrial application.Taking use of improved circle heat treatment technology,a serious of fine duplex microstructure with grain diameter about 20μm were obtained.The evolvement of microstructure during circle heat treatment was also studied.The results show that with the increase of the circles,the uniformity and the spheroidicity of the materials were largely inproved,and duplex microstructure γ TiAl alloy with varied fractions of lamellar could be got by changing time and temperature of circle heat treatment (CHT).更多还原