Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7972971 | Materials Science and Engineering: A | 2018 | 30 Pages |
Abstract
The microstructure, texture and mechanical properties evolution of the extruded fine-grained Mg-(1, 5) Y (wt%) alloy sheets were investigated during annealing. The as-extruded sheets exhibited a fully dynamic recrystallized (DRXed) microstructure consisting of uniform and fine equiaxed grains (5.7-8.7â¯Âµm) and a small amount of YH2 second phase particles. Both sheets exhibited significant thermal stability at 300â¯Â°C annealing and remarkable grain growth at temperatures higher than 400â¯Â°C. The measured grain growth activation energy (Q) of Mg-1Y at all temperatures tested was 91â¯Â± 3â¯kJ/mol, suggesting that the growth was controlled by grain boundary diffusion. Meanwhile, for Mg-5Y alloy at lower temperatures (300-400â¯Â°C), the Q value (59â¯kJ/mol) indicated that the grain growth was controlled by grain boundary diffusion while the Q value (175â¯kJ/mol) at higher temperatures (400-450â¯Â°C) implied that lattice self-diffusion controlled the process. A representative rare-earth texture was present for both sheets in the as-extruded condition, and remarkable basal texture weakening was observed with the grain growth during each isothermal annealing process. The texture weakening can be ascribed to the preferential growth of non-basal oriented grains based on the EBSD analysis, which was likely related to the segregation of Y atoms at grain boundaries. The microhardness and grain size relationship can be described well by the Hall-Petch relation for all the annealed sheets, while the yield stress was not the case indicating that the macroscopic strength was more sensitive to the texture than the localized microhardness.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
G.H. Huang, D.D. Yin, J.W. Lu, H. Zhou, Y. Zeng, G.F. Quan, Q.D. Wang,