Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7972089 | Materials Science and Engineering: A | 2018 | 22 Pages |
Abstract
An ultrafine microstructure consisting of α grains (~ 0.51â¯Âµm) and a small amount of β phase was successfully achieved in a friction stir-processed (FSPed) Ti-6Al-4V alloy. The fraction of high angle grain boundaries (HAGBs) with random crystallographic orientations reached 89.3% revealed that dynamic recrystallization was responsible for the ultra-grain refinement mechanism during friction stir processing (FSP). Low-temperature superplasticity (LTSP) of such an ultrafine microstructure was demonstrated in the temperature range of 550-650â¯Â°C and strain rates of 1â¯Ãâ¯10â4-3â¯Ãâ¯10â3 sâ1. Specifically, an extremely superior LTSP of 1130% was achieved at 600â¯Â°C and 3â¯Ãâ¯10â4 sâ1, which was explained by means of the ultrafine equiaxed grains, a large proportion of HAGBs with random orientations as well as the presence of β phase. The predominant superplastic deformation mechanism was considered as grain boundary sliding associated with grain boundary diffusion.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Wenjing Zhang, Hua Ding, Minghui Cai, Wenjing Yang, Jizhong Li,