A texture connection model of as-extruded magnesium alloy in semi-solid partial remelting process

XH Zhang and JQ Li and XD Ran and Q Chen, JOURNAL OF MATERIALS SCIENCE, 58, 1330-1344 (2023).

DOI: 10.1007/s10853-022-08065-z

This study investigated the texture evolution and its effects on the microstructure, particularly coalescence growth of grains, of an as- extruded magnesium alloy in semi-solid partial remelting process (PRMP) based on experiments and atomistic simulation. The results showed that the percentage of texture (10(sic)0)< 0001 > and (11(sic)0)< 0001 > formed in extrusion grew as the soaking times increased in PRMP. Both Ostwald ripening (OR) and coalescence growth of grains were detected. A model called texture connection (TC) was developed to discuss the relationship between coalescence growth and texture in PRMP. For ST (sheet texture, both 0001 and (10(sic)0) parallel respectively), FT15 (fiber texture, 0001 parallel, (10(sic)0) with an angle of 15 degrees) and PT15 (plane texture, (10(sic)0) parallel, 0001 with an angle of 15 degrees) cells, the neighboring grains combined to form a bigger grain with few defects. Dislocations were observed in process of coalescence growth. The types of dislocations depended on the texture and formed dislocations' position. For FT15 cells, 1/3 (sic)110 edge dislocation was formed between (10(sic)0) prismatic planes, and 1/3 10(sic)0 screw dislocation arose between (0001) (basal planes. The increased energy of freshly generated dislocations hindered grains coalescence growth. Especially for FT30, PT30 and FP5 (both 0001 and (10(sic)0) with an angle of 5 degrees) cells, such that they could not grow by merging. A screw dislocation with Burger's vectors of 101X was observed using HRTEM. The TC model appropriately explained why the texture percentage grew with soaking time in PRMP. GRAPHICS

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