Laser additive manufacturing of titanium alloys: process, materials and post-processing

Laser additive manufacturing (LAM) of titanium (Ti) alloys has emerged as a transformative technology with vast potential across multiple industries. To recap the state of the art, Ti alloys processed by two essential LAM techniques (i.e., laser powder bed fusion and laser-directed energy deposition) will be reviewed, covering the aspects of processes, materials and post-processing. The impacts of process parameters and strategies for optimizing parameters will be elucidated. Various types of Ti alloys processed by LAM, including α-Ti, (α + β)-Ti, and β-Ti alloys, will be overviewed in terms of microstructures and benchmarking properties. Furthermore, the post-processing methods for improving the performance of LAM-processed Ti alloys, including conventional and novel heat treatment, hot isostatic pressing, and surface processing (e.g., ultrasonic and laser shot peening), will be systematically reviewed and discussed. The review summarizes the process windows, properties, and performance envelopes and benchmarks the research achievements in LAM of Ti alloys. The outlooks of further trends in LAM of Ti alloys are also highlighted at the end of the review. This comprehensive review could serve as a valuable resource for researchers and practitioners, promoting further advancements in LAM-built Ti alloys and their applications.