Abstract

Metal additive manufacturing (MAM) is an emerging technology to produce complex end-use metallic parts. To adopt MAM for manufacturing numerous engineering parts used in critical applications, a thorough understanding of the relationship between the complex thermal cycles in MAM and the unique heterogeneous microstructures of MAM parts need to be established. This review article provides a comprehensive overview of the evolution of heterogeneous microstructures in MAM parts, including melt pool boundaries, heterogeneous grain structure, sub-grain cellular structure, matrix supersaturation, segregation, phase transformation, oxides formation, and texture. The evolution of residual stresses and the anisotropy in MAM parts and the post-MAM heat treatment effects on the microstructural evolution are also discussed. This review covers the microstructural aspects of most engineering materials in particular steels, high entropy alloys, aluminum alloys, titanium alloys, nickel-base superalloys, and copper alloys, with a primary focus on the parts manufactured using selective laser melting, direct energy deposition, and electron beam melting processes.

Graphic Abstract

中文翻译：

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增材制造的金属零件的异质性：综述

摘要

金属增材制造（MAM）是生产复杂的最终用途金属零件的新兴技术。为了采用MAM来制造关键应用中使用的许多工程零件，需要全面了解MAM中复杂的热循环与MAM零件独特的异质微观结构之间的关系。这篇综述文章全面概述了MAM零件中异质微观结构的演变，包括熔池边界，异质晶粒结构，亚晶粒细胞结构，基体过饱和，偏析，相变，氧化物形成和织构。还讨论了MAM零件中残余应力和各向异性的演变以及MAM后热处理对显微组织演变的影响。

图形摘要