Significant strain hardening ability of AZ91 magnesium alloy fabricated by spark plasma sintering

The strain hardening behavior of AZ91 alloys fabricated by spark plasma sintering (SPS) under different sintering temperatures was investigated by compression at room temperature. The sintered AZ91 alloys with random texture exhibit high yield strength and significant strain hardening ability. The hardening abilities (including strain hardening rate, strain hardening exponent and hardening capacity) increase with increasing sintering temperature. The strain hardening of sintered AZ91 alloys is dominated by dislocation slip and accompanied with extension twinning. The increment of hardening abilities is mainly due to the increasing of dislocation induced strain hardening because the rate of dislocation propagation is enhanced by coarse-grain. Additionally, the strain hardening induced by twinning is suppressed by fine-grain and intragranular lamellar Mg17Al12 precipitate.