Hot working parameters and mechanisms in as-cast Mg-3Sn-1Ca alloy

摘要

The hot working characteristics of as-cast Mg-3Sn-1Ca alloy have been studied using processing-map technique and the kinetic rate equation. The map exhibited two domains; one in the lower strain rate range (0.0003-0.01 s~(-1)) and the other in the higher strain rate range (0.1-10 s~(-1))-both falling in the same temperature range of 350-550 s~(-1). Hot extrusion at 500 ℃ and a speed corresponding to an average strain rate of 3 s~(-1) exhibited dynamically recrystallized microstructure. The estimated apparent activation energy values are higher than those for self-diffusion in pure magnesium suggesting that the large volume fraction of MgSnCa intermetallic particles causes significant back stress.