Effect of B_4C reinforcement and hot rolling on microstructure and mechanical properties of WE43 magnesium matrix composite

摘要

In this study, WE43 alloy matrix composites, reinforced with 2.5, 5, 7.5, and 10 wt% B_4C particles have been produced by the stir casting technique at 750 ℃. Cast ingots of the matrix alloy and the composites were then subjected to hot rolling at 480 ℃. After that, the effect of B_4C additions (0-10 wt%) as well as hot rolling on the microstructure and mechanical properties of WE43 alloy were investigated. Microstructural characterization following hot rolling revealed a relatively uniform distribution of B_4C particles, well-bonded B_4C particles to the matrix, and a minimal porosity level. Further, both as-cast and hot-rolled composites have shown considerable grain refinement and hence improved mechanical properties compared to unreinforced alloy. Twinning was the dominant deformation mechanism in the hot-rolled WE43 alloy, whereas dynamic recrystallization occurred extensively in hot-rolled composites. It was observed that tensile strength and hardness values were improved not only as B_4C content increased but more due to the rolling effect; however, elongation to fracture was reduced. Maximum ultimate tensile strength of ～284 MPa and yield strength of ～259 MPa with an improved hardness to ～97 HB were obtained for the hot-rolled WE43-10%B_4C composite.