激光3D打印工艺对钛合金质量的影响

为了解决传统锻造方法锻造TC4钛合金时容易造成的生产效率低且锻造形状简单等问题,对TC4钛合金进行了激光3D打印,并确定了最佳激光3D打印工艺参数.利用金相显微镜和扫描电子显微镜对TC4钛合金单道打印层的成形质量、显微组织与相组成进行了分析.利用显微维氏硬度计和万能拉伸试验机测量了打印层的硬度和拉伸力学性能.结果表明,在最佳工艺参数下TC4钛合金打印成形良好,其打印层组织主要由片层状α固溶体组成.打印层的Z向拉伸强度指标低于XY向,而Z向拉伸塑性指标高于XY向,且Z向强度和塑性指标均超越了TC4锻件国家标准(GB/T 25137-2010).同时Z向和XY向拉伸断口形貌均为塑性断口.

Effect of laser 3D printing process on quality of titanium alloy

In order to solve the problems of low production efficiency and simply forged shapes of TC4 titanium alloy prepared with the traditional forging method, laser 3D printing of TC4 titanium alloy was carried out, and the optimum technological parameters for the laser 3D printing were determined. Forming quality, microstructure and phase composition of single channel printed layer of TC4 titanium alloy were analyzed with optical microscope(OM)and scanning electron microscope(SEM). The hardness and tensile mechanical properties of printed layer were measured using microhardness tester and universal tensile testing machine. The results show that the TC4 titanium alloy can be successfully printed under the optimum technological parameters, and the microstructure of printed layer is mainly composed of lamellar α solid solution. The tensile strength indexes in the Z direction of printed layer is lower than those in the XY direction, while the tensile plasticity indexes in the Z direction is higher than those in the XY direction. Both strength and plasticity indexes in the Z direction surpass the national standard of TC4 forgings(GB/T 25137-2010). Meanwhile, the tensile fracture morphologies in both Z and XY directions show plastic fractographs.