Investigation on the synergistic improvement of strength and plasticity in Tip/AXM310 magnesium matrix composites fabricated by melt casting-extrusion process

Abstract

In this work, the Tip/AXM310 composites were prepared by combining mechanical stirring and hot extrusion processes. The effect of different addition quantities of Ti particles on the microstructure and mechanical properties of xTip/AXM310 (x = 0, 1, 2, 3 wt.%) composites was investigated, and the strengthening mechanism of the composites was discussed. The results demonstrated that the addition of Ti particles can refine the grains and promote the precipitation of the second phase in the matrix. As the amount of added Ti particles increases, the grain size and texture intensity of the composites gradually decrease, while the recrystallization fraction gradually increases. During the homogenization process prior to extrusion, the second phase of the Tip/AXM310 composites is transformed from C36-(Mg, Al)₂Ca to C15-Al₂Ca. The 2% Tip/AXM310 composite exhibits the best mechanical properties, with a yield strength of 282 MPa, an ultimate tensile strength of 302 MPa, and an elongation of 14.2%. This represents significant improvements of 16.7, 38.9, and 36.5% respectively compared to the matrix alloy. The improvement in the yield strength of the composites is mainly attributed to a combination of grain refinement, Orowan strengthening, and thermal mismatch strengthening. The theoretical yield strength values of the composites calculated from the equations of the four strengthening mechanisms are basically consistent with the experimental values.