Microstructure refinement induced by elastic compressive stress in Ti-6Al-4V alloy

• Published in: Journal of alloys and compounds 2024-04, Vol.981, p.173700, Article 173700
• Main Authors: Zhang, Yinan, Jiang, Yuan, Si, Kunlun, Xin, Shewei, Zhang, Siyuan, Hou, Fengqi, Zhang, Kai, Hai, Jiawei, Xiao, Lehao, Yang, Yi, Wang, Hao, Huang, Aijun, Zhang, Lai-Chang
• Format: Article
• Language: English
• Subjects: Elastic compressive stress; Microhardness; Microstructure; Phase transformation; Titanium alloy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2024.173700

The β→α transformation is a crucial and fundamental phase transformation in titanium and its alloys. This work investigated the effect of elastic compressive stress (ECS) on the microstructure and mechanical property during cooling from β phase region to α + β phase region in Ti-6Al-4V alloy. Results indicated that ECS in this process results in significant refinement and increased aspect ratios of α lamellae (αL) and α colonies (αC). These changes are attributed to the enhanced phase transformation driving force to promote nucleation of α lamellae. The ECS-cooling induced alloy exhibits higher hardness than the stress-free counterpart, mainly resulting from the refined microstructure. This work provides a potential method to tailor the microstructure and improve the mechanical properties of Ti alloys. [Display omitted] •The phenomena of αL refinement are for the first time identified under elastic stress, and the formation mechanism of such phenomena was elucidated.•The elastic compressive stress influences Gibbs free energy are the main reasons for the refinement and variant selection of α lamellae and α colony in Ti-6Al-4V alloys.