铝合金激光熔化沉积应力场及力学性能分析

Stress field and mechanical properties of laser metal deposited aluminum alloys

采用激光熔化沉积工艺对6 mm厚的ZL114A铝板中的通槽进行了修复试验.试验中采用AlSi10Mg粉末作为沉积过程的填充材料.为了选择合适的激光扫描方法,通过数值模拟的方式,探究了不同扫描路径下产生的残余应力情况.模拟结果显示,相比于自一侧向另一侧平行扫描,自下向上逐层扫描方式更有助于减小残余应力,残余应力分布也更均匀.采用自下向上的逐层扫描方式实现了铝板通槽的激光熔化沉积的工艺试验,并探索了缺陷及热输入对试件力学性能的影响.结果表明,通过工艺试验得到的沉积试件,最优性能的试件抗拉强度为268 MPa,达到母材的89%.试件断裂并未沿着沉积区与母材的界面处断裂,而是在沉积区内部层与层界面间的搭接区域断裂.

Through grooves in the 6 mm thickness ZL114A aluminum plate were repaired by the laser metal deposition process, and the filling powder was AlSi10Mg powder. In order to determine the scanning strategy, the residual stress generated with different scanning strategies was calculated by numerical simulation. The process of laser melting deposition was realized by the path scanning method with the smallest residual stress, and the influence of defects and heat input on the mechanical properties of the test workpiece was further studied. The results show that the layerby-layer scanning strategy generated less the residual stress compared with the parallel scanning strategy. In terms of mechanical properties, by optimizing the process, the tensile strength of the tensile specimens has reached 268 MPa, which is 89% of the tensile strength of the substrate. Besides, the fracture location of the specimen was not along the interface between the deposition area and the substrate, but in the overlapping area between the deposition tracks.