AbstractThe hot working behavior of Mg-3Sn-2Ca alloy has been investigated in the temperature range 300–500 oC and strain rate range 0.0003–10 s-1, with a view to evaluate the mechanisms and optimum parameters of hot working. For this purpose, a processing map has been developed on the basis of the flow stress data obtained from compression tests. The stress-strain curves exhibited steady state behavior at strain rates lower than 0.01 s-1 and at temperatures higher than 350 oC and flow softening occurred at higher strain rates. The processing map exhibited two dynamic
recrystallization domains in the temperature and strain rate ranges: (1) 300–420 oC and 0.0003–
0.003 s-1, and (2) 420–500 oC and 0.003–1.0 s-1, the latter one being useful for commercial hot
working. Kinetic analysis yielded apparent activation energy values of 161 and 175 kJ/mole in
domains (1) and (2) respectively. These values are higher than that for self-diffusion in magnesium
suggesting that the large volume fraction of intermetallic particles CaMgSn present in the matrix
generates considerable back stress. The processing map reveals a wide regime of flow instability
which gets reduced with increase in temperature or decrease in strain rate.