Multiscale analysis of high impact toughness in a novel low-cost titanium alloy

作者：Zhongli Qiao, Qinyang Zhao, Zixuan Meng, Ping Guo, Runqi Zhang, Yan Zhang, Shuo Song, Cheng Lin, Kuaishe Wang, Yongqing Zhao · 发表于：Journal of Materials Research and Technology · 年份：2025 · DOI：10.1016/j.jmrt.2025.08.227 · 被引用次数：6 · 研究领域：Titanium Alloys Microstructure and Properties、High-Velocity Impact and Material Behavior、Microstructure and mechanical properties

This study systematically investigates the deformation behavior of novel low-cost Ti-6Al-4V-0.4Fe-0.6Mo alloy with varying microstructures under dynamic impact loading. The microstructures with equiaxed and bimodal were fabricated by controlling the temperatures (880°C, 900°C and 920°C) and cooling rates (air cooling, AC and furnace cooling, FC). Charpy impact testing results show that the 920FC sample, featuring large equiaxed α phases (average size: 8.2 μm), α lamellae (thickness: 1.5 μm), and retained β-phases, exhibits the highest impact toughness of ∼62.5 J/cm 2 . Compared with 880FC (∼45.3 J/cm 2 ), 900FC (∼42.1 J/cm 2 ) and Ti-6Al-4V alloys with equiaxed microstructures (∼50 J/cm 2 ), the impact toughness is improved by 38%, 48% and 25%, respectively. Moreover, the impact toughness of the 920AC sample (∼47.6 J/cm 2 ) is 20% higher than that of 880AC (∼39.5 J/cm 2 ) and 900AC samples (∼39.5 J/cm 2 ). Microstructural analyses results show that both 920AC and 920FC samples exhibit low α phase aspect ratios, high α phase spheroidization proportion, and large α grain sizes. The 920FC sample has a percentage of twin boundaries as high as 58.7%, which is the core mechanism for its superior impact toughness over the 920AC sample. Interestingly, we found that twinning nucleation in both α and secondary α phases (α s ) is induced by stacking faults and the abundant stacking faults form martensite 9R phase. The coarsening and growth of twins are affected by dislocation slip. In a...