The microstructural evolution with respect to the precipitation of silicides and ordered α₂ phase in near-α TA29 Ti alloy during thermal exposure at 650 °C for different time has been investigated in this work, and the subsequent mechanical properties have been evaluated by tensile and fracture toughness tests. The results indicated that the (Ti, Zr)₆Si₃ silicides firstly precipitated in residual β films, and then began to precipitate within α plates. A large number of fine α₂ precipitates showing sphercial shape concurrently formed in the α plates at a short time. The ordered α₂ precipitates asymmetrically grew up along different crystallographic directions with increasing exposure time, leading to their spherical shape change to ellipsoidal shape and finally olive shape, in which the long axis was perpendicular to [0001]_α as viewed along [$\overline{2}$110]_α direction. The number density of ordered α₂ was obviously decreased after 1000 h due to Ostwald ripening. The precipitation of silicides and ordered α₂ phase improved the tensile strength but deteriorated the ductility and fracture toughness, whereas the strength was decreased and the room temperature elongation was recovered slightly after long-term exposure because of α₂ ripening.

相对于硅化物的析出的组织演变和有序α ₂相在近α在650℃下热暴露不同的时间期间TA29 Ti合金已在此工作了研究，以及随后的机械性能已被拉伸评估和断裂韧性测试。结果表明，（Ti，Zr）₆ Si ₃硅化物首先在残留的β膜中析出，然后开始在α板中析出。大量微细的α _2级的析出物表示同时形成在α板在短时间内sphercial形状。α有序₂析出物不对称地长大随着增加曝光时间不同的结晶方向，从而导致它们的球形形状变化到椭圆形的形状并最后橄榄形状，其中长轴是垂直于[0001] _α沿着观察[$\overline{2}$110] _α方向。的有序α的数密度₂明显1000小时后降低由于Ostwald熟化。硅化物的沉淀和有序α ₂相提高了抗张强度，但降低的延展性和断裂韧性，而强度降低和室温伸长率略微后回收长期暴露由于α ₂催熟。