增材制造金属结构件残余应力的研究进展

Research Progress on Residual Stress of Metal Structure by Additive Manufacturing

增材制造技术近年来取得了重大进展,金属增材制造可以三维成型精度高的复杂形状零件,在各行业的应用中具有独特优势。然而,增材制造金属零件成形时由于高温度梯度会引起复杂残余应力。简要分析了增材制造技术的特点,重点总结了激光选区熔化和电弧增材制造的工艺原理。在此基础上,详细综述了增材制造过程中残余应力的产生机制及测量方法,其中,温度梯度机制是解释残余应力产生机制最常用的方法。针对残余应力的测量,分别从无损检测和破坏性检测两方面进行归纳,最常用的破坏性检测残余应力的方法是轮廓法和钻孔法,而无损检测的方法是X射线衍射法。并且总结了残余应力的调控方法,包括工艺参数调控、预热缓冷及重熔调控、结构设计调控、辅助外场调控、后处理调控。最后简要总结增材制造金属结构件残余应力研究中亟待解决的问题,并展望了金属增材制造的发展方向。

Additive manufacturing has made significant progress in recent years,and metal additive manufacturing can 3D fabricate complex-shaped parts with high precision,which has unique advantages in applications of various industries.However,the high temperature gradient in the forming of metal additive manufacturing parts can cause complex residual stresses.In this review,the characteristics of additive manufacturing technology are briefly analyzed,and the processing principles of selective laser melting and wire and arc additive manufacturing technology are emphatically summarized.On this basis,the generation mechanism and measurement method of residual stress from the additive manufacturing process are reviewed in detail.The temperature gradient mechanism is the most commonly used method to explain the residual stress generation.Regarding the measurement of residual stress,it is summarized from two aspects of non-destructive testing and destructive testing.The common destructive testing methods for residual stress are profile method and drilling method,while the common non-destructive testing method is X-ray diffraction method.The control methods of residual stress are also summarized,including processing parameters optimization,preheating and slow cooling and remelting,structural design,auxiliary external field,post-processing.Finally,a brief summary of the residual stress research in additive manufacturing of metal structural parts and the problems to be solved are summarized,and the development direction of additive manufacturing is prospected.