Recent Progress in Laser Additive Manufacturing of Intermetallic Alloys: Defects, Microstructure, and Mechanical Properties

Intermetallic alloys offer exceptional high-temperature mechanical properties and low densities, thus rendering them suitable for a wide range of applications in aviation and spacecraft. However, their inherent brittleness at room temperature poses challenges in the manufacture of complex geometries. Hence, Laser additive manufacturing (LAM) has emerged as a promising approach to investigate the potential limitations of these materials. This review discusses the key findings and challenges associated with the LAM of intermetallic alloys, particularly NiAl, Ni 3 Al, and TiAl, whose engineering applications are substantial. It provides an overview of typical defect morphologies, formation mechanisms, and strategies to prevent cracks and pores. Additionally, it presents an analysis of the microstructural characteristics of as-built and post-treated samples compared with those of samples prepared conventionally. Furthermore, the mechanical properties of the above-mentioned alloys at both room and high temperatures are reviewed, thus highlighting the effects of post-treatment processes. This review concludes with summary tables detailing the mechanical properties, which serve as useful references for researchers.