激光选区熔化复合制造TC4钛合金组织性能研究

Study on Microstructure and Properties of TC4 Titanium Alloy Fabricated by Laser Selective Melting Composite

采用选区激光熔化技术(SLM)在锻造后的TC4合金基体上制备TC4钛合金增材锻件复合成形件,并采用金相显微镜(OM)、扫描电镜(SEM)、显微维氏硬度计和拉伸试验机等试验设备,分析了不同SLM参数下TC4钛合金复合成形件微观组织及力学性能。结果表明:复合试样微观组织分为锻件基体区、结合区以及增材区三个区域。增材区与锻件区之间界线清晰,无未熔合、气孔、裂纹等缺陷。锻件区组织为等轴组织,增材区为相互交错的针状α′马氏体组织。性能试验结果表明:增材区和结合区抗拉强度及屈服强度均显著优于锻件;其中结合区强度最高,增材区次之。综合考虑强度和塑性,激光功率为280 W,扫描速率为1100 mm/s下得到的复合试样拉伸性能最好。

TC4 titanium alloy additive forging composite parts have been prepared on the forged TC4 alloy substrate by selective laser melting(SLM).The microstructure and mechanical properties of TC4 titanium alloy composite parts under different SLM parameters have been analyzed by metallographic microscope(OM),scanning electron microscope(SEM),hardness tester and tensile tester.The results show that the microstructure of the composite sample is divided into three regions:forging basal body region,bonding region and additive region.The boundary between the additive zone and the forging zone is clear,and there are no defects such as incomplete fusion cracks.The microstructure of the forging zone is equiaxed structure,and the additive zone is interlaced acicularα′martensite structure.The performance test results show that the tensile strength and yield strength of the additive zone and the bonding zone are significantly better than those of the forging.The bonding zone has the highest strength,followed by the additive zone.Considering the strength and plasticity,the tensile properties of the composite specimens obtained by laser power of 280 W and scanning rate of 1100 mm/s are the best.