Synergistic Enhancement of Strength and Creep Resistance in Additive Manufacturing Ti‐6.5Al‐2Zr‐Mo‐V Alloy via In Situ Co‐Modification With Si and Y Elements
Zishuo Ma, Qi An, Delong Gong, Junshi Li, Lihua Cui, Yuyang Liu, Jiayu Tian, Rui Zhang, Shuai Wang, Liqin Wang, Lujun HuangABSTRACT
The demand for advanced aerospace components necessitates near‐α titanium alloys with enhanced high‐temperature performance and compatibility with additive manufacturing (AM). To address this, an in situ alloying strategy was employed to co‐modify a Ti‐6.5Al‐2Zr‐Mo‐V alloy with Si and Y during laser powder bed fusion. The added elements effectively tailored the microstructure, resulting in a uniform dispersion of nano‐Y 2 O 3 particles and, after annealing, the precipitation of sub‐micron (Ti,Zr) 5 Si 3 silicides at α/β interfaces. The modified alloy exhibited significantly enhanced tensile strength, reaching 1348.2 MPa at room temperature in the as‐built condition. After microstructural regulation via 900°C heat treatment, a basket‐weave structure was obtained, leading to a balanced strength‐ductility combination with a tensile strength of 1066.3 MPa and an elongation of 19.1%. The alloy also maintained superior tensile performance from 500°C to 700°C, and the creep life at 500°C was doubled compared to the unmodified counterpart, demonstrating exceptional creep resistance. The improvement is attributed to a synergistic mechanism combining solid‐solution strengthening, effective dislocation pinning by thermally stable Y 2 O 3 nanoparticles, and interface stabilization via silicides that collectively hinder dislocation glide and retard creep damage. This work provides a viable pathway for designing high‐performance AM titanium alloys for critical high‐temperature applications.