选区激光熔化铝合金缺陷的形成机制和对力学性能的影响:综述

The Formation Mechanism and Effect on Mechanical Properties of Defects of Aluminum Alloy by Selective Laser Melting:a Review

选区激光熔化(Selective laser melting,SLM)作为增材制造(Additive manufacturing,AM)技术的一种,其成形精度高,有利于实现更复杂的结构设计,适合铝合金复杂零部件的快速成形,被广泛应用于航空航天领域中。铝合金由于具有密度小、比强度高及优良的综合力学性能被广泛应用于航空航天、汽车等轻量化设计领域中。但是打印缺陷的形成严重限制了SLM工艺铝合金的推广应用。因此,了解缺陷的形成机制从而控制缺陷的产生对SLM工艺铝合金的应用有着重要的意义。SLM工艺打印缺陷主要分为裂纹,孔隙,残余应力和各向异性,球化。打印缺陷主要由不恰当的工艺参数导致。本文以Al-Si系铸造铝合金为研究对象,综述了SLM制备铝合金打印缺陷形成机制的研究进展,总结了缺陷形成的影响因素,并归纳了缺陷与铝合金力学性能之间的影响关系,孔隙率过多容易导致铝合金的拉伸和疲劳性能降低,通过选择适当的后处理可以有效改善其疲劳性能。

As an additive manufacturing technology,selective laser melting(SLM)is capable of forming complex structures with high forming precision and is suitable for rapid prototyping of complex-structure components made of aluminum alloys.Due to their high specific strength and excellent mechanical properties,aluminum alloys are widely used in aerospace,automobile,and other industries that require lightweight materials.However,SLM aluminum alloys are prone to cracks,pores,residual stress,anisotropy,and balling.Defects are mainly caused by inappropriate process parameters and can restrict the use of SLM aluminum alloys.Therefore,insights into the formation mechanism of these defects can help control and mitigate their effects.In this study,the common Al-Si cast aluminum alloy was used to review the current state of research on the defect formation mechanism of SLM aluminum alloys.This paper summarizes the effects of different process parameters on the defect formation and examines the relationship between defects and the mechanical properties of aluminum alloys.High porosity can reduce tensile strength and negatively affect the fatigue properties;however,fatigue resistance can be increased via an appropriate post-treatment.