Revealing the tensile creep behavior and mechanism of SiC particles reinforced AZ31 composite fabricated by liquid metallurgy

Abstract

Constant engineering stress tensile creep behavior of AZ31 magnesium matrix composites with SiC particles in 20% volume fraction and a mean diameter of 8.6 μm, fabricated by liquid metallurgy, was performed at the temperature range of 473–623 K, and the stress level range of 7–70 MPa. The minimum creep rates of the as-cast composites reveal better creep resistance at high temperatures and low stresses compared with those of unreinforced AZ31 alloy. The high apparent stress exponents and apparent activation energies of the composites imply the presence of threshold stress in the creep behavior. The true stress exponent of the composite was calculated to be ∼5, indicating that the possible creep mechanism is the climb-controlled creep model controlled by lattice diffusion.