不同振镜精度下选区激光熔化Ti6Al4V零件性能的对比分析

Research on the properties of Ti6Al4V parts prepared by selective laser melting under different galvanometer accuracy

为了研究振镜精度对选区激光熔化成形件的影响,在3种不同振镜精度下制备Ti6Al4V试样,并对零件的硬度、致密度、物相、微观组织、力学性能和断口形貌进行分析.结果表明,3组试样的物相均为α/α'相,随着振镜精度变差试样的致密度、维氏硬度、屈服强度和应变值呈下降趋势;振镜校准精度在0.025 mm范围内,拉伸件的断裂应变为10.15%,扫描轨迹未出现明显偏移;振镜校准精度在0.05 mm范围内,拉伸件的断裂应变为8.99%,扫描轨迹未出现明显偏移,断口边缘出现了夹渣,零件表面出现微小的气孔,抗拉强度与屈服强度变化不明显,断后伸长率有所下降;振镜校准精度在0.09 mm范围内,拉伸件的断裂应变为8.37%,部分扫描轨迹出现了10μm的偏移,零件表面出现明显的大气孔,断口两侧出现夹渣,抗拉强度变化不大,屈服强度略微下降,断后伸长率明显降低.分析认为振镜校准精度在0.05 mm范围内,打印过程熔道未出现明显的偏移现象,振镜校准精度在0.09 mm范围内,部分打印点出现了漂移现象,引起了熔道的偏移,脱离了原始的规划路径,导致气孔、飞溅或未熔粉末的产生,降低了零件的致密度及拉伸件的承载面积,引起了断后伸长率的降低.

In order to study the influence of galvanometer accuracy on selective laser melting forming parts,Ti6Al4V samples were prepared under three different galvanometer accuracy,and the hardness,density,phase,microstructure,mechanical properties,and fracture morphology of the parts were analyzed.The results showed that the phases of the three groups of samples were allα/α',and the density,Vickers hardness,yield strength,and strain values of the samples decreased as the galvanometer accuracy deteriorated.When the galvanometer calibration accuracy was within 0.025 mm,the fracture strain of the tensile specimen was 10.15%,and the marking line did not show significant deviation.When the galvanometer calibration accuracy was within 0.05 mm,the fracture strain of the tensile specimen was 8.99%,the marking line did not show significant deviation,and the edge of the fracture showed inclusions,while the surface of the part showed small pores.The tensile strength and yield strength changed insignificantly,but the elongation after fracture decreased.When the galvanometer calibration accuracy was within 0.09 mm,the fracture strain of the tensile specimen was 8.37%,and some marking lines deviated by 10μm.The surface of the part showed obvious large pores,and inclusions appeared on both sides of the fracture.The tensile strength changed little,the yield strength decreased slightly,and the elongation after fracture decreased significantly.It was analyzed that within a galvanometer calibration accuracy of 0.05 mm,the melting track during the printing process did not show significant deviation.Within a galvanometer calibration accuracy of 0.09 mm,some printing points showed drifting phenomena,causing the melting track to deviate and deviate from the original planned path,resulting in the generation of pores,splashing,or unmelted powder,which reduced the density of the parts and the bearing area of the tensile specimens,leading to a decrease in the elongation after fracture.