激光增材制造近 β 钛合金的微观组织调控 与强韧性协同提升机制

Near β titanium alloys, due to their outstanding properties such as high specific strength and excellent fracture toughness, are indispensable key structural materials in cutting-edge fields like aerospace. However, their traditional manufacturing processes face numerous challenges when it comes to preparing complex components. Laser additive manufacturing (LAM) technology, as a disruptive manufacturing paradigm, provides a revolutionary approach for the integrated forming of complex structures of near-β titanium alloys and customized control of microstructure. This paper systematically reviews the research progress in recent years on microstructure regulation and the synergistic improvement of strength and toughness of near-β titanium alloys through laser additive manufacturing technology. It mainly expounds how the unique non-equilibrium thermal process of LAM induces the formation of typical microstructures such as fine grains, metastable phases (martensite phase, ω phase), and high-density dislocations, and deeply analyzes multiple strengthening and toughening mechanisms such as phase transformation strengthening, fine grain strengthening, solid solution strengthening, and dislocation strengthening based on these structures. Meanwhile, systematically summarized the key roles of post-treatment strategies such as hot isostatic pressing (HIP), heat treatment (HT), and surface modification in eliminating defects, optimizing the microstructure, and ultimately achieving an excellent match of strength and toughness. The results show that combining the unique microstructure endowed by laser additive manufacturing with precise post-processing control is the core strategy to break the inherent shackles of strength and toughness of near β titanium alloys and achieve a breakthrough in their comprehensive performance limit, laying an important theoretical and technical foundation for their engineering application in high-performance fields.