激光选区熔化成形高性能钛合金微观组织调控与力学性能分析

Microstructure Adjustment and Mechanical Properties Analysis of High-performance Titanium Alloy Manufactured by Selective Laser Melting

采用激光选区熔化成形技术制备Ti6Al4V合金试件,通过光学显微镜、扫描电镜和断口形貌分析,系统研究了成形态试样显微组织对力学性能的影响。对比不同打印参数下的微观组织特征,显示沿沉积方向形成β柱状晶,晶内主要分布着针状马氏体α′相,α′相含量越高塑性越差,控制工艺参数可以使针状马氏体α′相原位分解形成α+β相,有利于提高塑性。通过调节激光功率和扫描速度,制备了综合力学性能优异的试件,其抗拉强度达到1 301 MPa,屈服强度达到1 102 MPa,延伸率为7.94%。选区激光熔化成形钛合金经组织调控发生原位分解后,拉伸性能得到提高。

Ti6 Al4 V alloy samples were prepared by selective laser melting, and the effect of microstructure on mechanical properties was systematically studied by optical microscope, scanning electron microscopy and fracture morphology analysis. Comparing the microstructure characteristics under different parameters, the microstructure features show that columnar β crystal is formed along the deposition direction, and the acicular martensite α′ phase is mainly distributed in the crystal. With the increase of α′ phase content, the plasticity becomes worse. By controlling the process parameters, the acicular martensite α′ decomposes in situ to form α + β phase, which is conducive to improving the plasticity. By controlling the laser power and scanning speed, samples with excellent comprehensive mechanical properties were prepared. The tensile strength reached 1 301 MPa, the yield strength reached 1 102 MPa, and the elongation was 7.94%. Tensile properties can be improved by microstructure regulation of in-situ analysis for titanium alloy manufactured by selective laser melting.