Progress and challenges of laser direct manufacturing of large titanium structural components

The technological and economic advantages of laser direct manufacturing of large titanium structural components in comparison to the traditional forging process are briefly summarized and their industrial application potentials in the aerospace industries are prospected. State of the art on processing optimization, microstructure and mechanical properties control, equipment development and engineering applications in aerospace industries are reported. The technological challenges facing the further development of the technology is reviewed. Physical and metallurgical complexities of laser direct manufacturing of large titanium structural components are analyzed with a special emphasis on the thermal physics of the deposition process, extraordinary metallurgical kinetics of the laser induced high-temperature melt pool, the forming mechanisms of the unique non-equilibrium rapidly solidified structures and various inherent internal defects. It is pointed out that efficient prevention of ″component distortion and cracking″ as well as control of ″internal structure and defects″ are currently the two ″bottle-neck″ obstacles challenging the further development and industrial applications of the revolutionary advanced manufacturing technology. Intensive basic research and more fundamental understanding on the non-steady state evolution and interaction behaviors of internal stresses and the forming mechanisms of rapid solidification microstructures and internal defects are needed in order to effectively overcome the above ″bottle-neck″ problems.