采用激光3D打印技术制备了TC4合金试样,研究了固溶时效处理对激光3D打印TC4合金显微组织和力学性能的影响规律。结果表明:随着固溶温度升高,初生α相的粗化现象越发明显;随着固溶时间延长,α相转变为β相的数量增多;随着时效温度升高,残余β相中析出的次生α相的长宽均有所增加;随着时效时间延长,次生α相的体积分数有所增加;在时效处理过程中,初生α相中析出了次生网状β相,初生α相之间的β相中析出了次生α相,这两种次生相的析出会影响试样的性能。在950 ℃/1 h/WQ+550 ℃/4 h/AC固溶时效条件下处理后,钛合金的室温抗拉强度为990 MPa,屈服强度为920 MPa,伸长率为11.5%,断面收缩率为27.5%,达到了锻件的国标要求;沉积态和固溶时效态拉伸试样的断口上均布满了韧窝,均为塑性断裂。

TC4 titanium alloy specimens are prepared via laser three-dimensional (3D) printing and the effect of solution-aging state on the microstructures and mechanical properties of the specimens is investigated. The experimental results show that an increase in solution temperature results in more obvious coarsening of the primary α phase. As the time in solution increases, more of the α phase transforms into the β phase. With respect to aging, as the temperature increases, the length and width of the secondary α phase precipitated from the residual β phase increase, and as the aging time increases, the volume fraction of the secondary α phase increases. During the aging treatment, the secondary reticular β phase is precipitated from the primary α phase, and the secondary α phase is precipitated from the β phase between the primary α phases. Owing to the precipitation of the two secondary phases, the properties of the specimens are affected. With treatment conditions at 950 ℃/1 h/WQ+550 ℃/4 h/AC, the TC4 titanium alloy shows the best mechanical properties. The room-temperature tensile strength is 990 MPa, the yield strength is 920 MPa, the elongation is 11.5%, and the area reduction is 27.5%. The fracture morphologies of the laser-3D printed TC4 titanium alloys in both the as-deposited and solution-aging states are laden with dimples and plastic fractures. Overall, the national standards for forgings have been met.