Balancing Strength and Toughness in Ti‐52221 Alloy: Effects of Heat Treatment

The balance between strength and toughness was generally difficult to achieve in metallic materials. To address this challenge, a novel Ti‐5Al‐2Mo‐2V‐2Zr‐2Cr‐1Nb (Ti‐52221) alloy was designed. Heat treatment was employed to enhance its properties, with a focus on investigating the effects of different cooling rates on microstructure and mechanical properties. Tensile and Charpy impact tests were conducted, with particular emphasis on the analysis of impact toughness. Electron backscatter diffraction was employed for microstructural characterization. The results showed that the cooling rate significantly affected the grain size and dislocation density of the alloy, thereby determining its mechanical properties. The sample subjected to multistep cooling exhibited a strength of 873 MPa, an elongation of 17%, and an impact toughness of 77 J. The excellent impact toughness originated from the high crack propagation energy, as well as the effects of deformation twinning and dislocations on crack propagation. This work revealed the potential for enhancing the overall performance of titanium alloys by optimizing the heat treatment process to tailor the microstructure.