Abstract: The large thickness (60 μm) AlSi10Mg alloy was formed by selective laser melting (SLM) technology, and the optimal printing parameters were determined by orthogonal experiments with density as the index. The microstructure, phase analysis and mechanical properties of AlSi10Mg alloy formed at different annealing temperatures (200, 300, 400, 500 ℃) were studied. The results show that when the laser power is 310 W, the scanning speed is 1 450 mm/s, and the scanning spacing is 95 μm, the density of AlSi10Mg alloy is the highest, reaching 99.92%. With the increase of annealing temperature, the weld pool boundary of the longitudinal section of AlSi10Mg molded part gradually becomes blurred, and the eutectic structure at the weld pool boundary gradually homogenizes. In the X-ray diffraction spectrum, the diffraction peak of AlSi10Mg powder corresponding to the forming part and annealed part is obviously shifted. When the annealing temperature is 500 ℃, the tensile strength of annealed samples decreases from 355 MPa to 102 MPa with the fracture of Si network, and the elongation rate increases from 1.65 % to 13.25 % with the increase of dimples.

Key words: vehicle and electromechanical engineering; selection laser melting; AlSi10Mg; microstructure; annealing; mechanical property

摘要： 通过选择性激光熔化(selective laser melting,SLM)技术成型大层厚(60 μm)AlSi10Mg合金，以致密度为指标设计正交实验确定最优打印参数，对不同退火温度(200、300、400、500 ℃)的AlSi10Mg成型件进行微观组织、物相分析和力学性能研究。结果表明：当激光功率310 W、扫描速度1 450 mm/s、扫描间距95 μm时，AlSi10Mg成型件的致密度最高，达到99.92%；随着退火温度的升高，AlSi10Mg成型件纵截面的熔池边界逐渐变得模糊，熔池边界共晶组织逐渐均匀化，X射线衍射谱中AlSi10Mg原始粉末与成型件及退火后成型件对应的衍射峰有明显偏移现象；当退火温度为500 ℃时，退火后成型件抗拉强度伴随Si网络的断裂从355 MPa降至102 MPa，延伸率随着韧窝的增多从1.65%升高至13.25%。

关键词: 车辆与机电工程；选区激光熔化；AlSi10Mg；微观组织；退火；力学性能