Effect of ECAP process on liquid distribution of AZ80M alloy during semi-solid isothermal heat treatment
(1. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
2. Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China)
2. Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610213, China)
Abstract: Two kinds of semi-solid samples of AZ80-0.2Y-0.15Ca (wt.%) (AZ80M) magnesium alloy were prepared by semi-solid isothermal heat treatment of materials with and without equal channel angular pressing (ECAP) process. The microstructures of initial and semi-solid treated samples were compared and analyzed. The results showed a significant difference in the liquid phase distribution between three-pass ECAP processed (3P) and as-received samples during the isothermal heating process. The semi-solid 3P sample showed a more uniform liquid distribution due to its smaller dihedral angle. Besides, the coarsening processes of solid grains of as-received and 3P samples were dominated by the coalescence and Ostwald ripening mechanism, respectively. The difference of coarsening processes was mainly related to the proportion of the high-angle grain boundaries in materials, which further affected the evolution behavior of the liquid pools.
Key words: AZ80M; equal channel angular pressing; semi-solid microstructure; liquid phase distribution; coarsening mechanism