层厚对内燃机用激光选区熔化成形Ti-5Al-2.5Sn钛合金组织与性能的影响

In fluence of Layer Thickness on Microstructure and Mechanical Properties of Selective Laser Melted Ti-5Al-2.5 Sn Alloy

研究了层厚对激光选区熔化(SLM)技术成形Ti-5Al-2.5Sn(Ti-Al-Sn)钛合金试样致密度、显微组织和力学性能的影响规律。结果表明,随着层厚的减小,激光体的能量密度将会提高,层厚度达到60μm时也同样能够制得致密度大于99.0%的Ti-Al-Sn合金试样。采用SLM工艺得到的Ti-Al-Sn合金试样主要包括3种显微组织,分别为针形α'马氏体组织、针形α'马氏体+岛形αm混合组织以及单纯的岛形αm组织。当层厚增加以及扫描速率变慢时,试样的冷却速率也逐渐降低。当层厚增加后,各个Ti-Al-Sn试样的力学性能测试结果都发生了降低的现象。各个层厚下得到的Ti-Al-Sn试样在室温下进行拉伸测试时都表现为韧性断裂特征。

The effect of layer thickness on the density, microstructure and mechanical properties of ti-5al-2.5 Sn (Ti-Al-Sn) titanium alloy was studied. The results show that with the decrease of thickness, the energy density of the laser body will be increased ,and the Ti-Al-Sn alloy sample with a density greater than 99.0% can be produced when the layer thickness reaches 60 μm. Using SLM technology of Ti-Al-Sn alloys mainly includes three kinds of microstructure, the needle alpha' martensite structure respectively, needle alpha martensite + island shape alpha m mixed groups and the pure form of alpha m group. As the thickness of the layer increases and the scanning rate slows down, the cooling rate of the sample decreases gradually. When the thickness of the layer was increased, the mechanical properties of the ti-al-sn samples were reduced. The Ti-Al-Sn samples obtained at different layers were characterized by ductile fracture at room temperature.