Solid solution strengthening behaviors in binary Mg–Y single phase alloys

Solid solution effects on the mechanical behavior of binary Mg–Y single phase alloys have been investigated in a temperature range from ambient to 350 °C with yttrium contents between 0.20 and 1.88 at.%. At room temperature, the hardness increases with the increasing Y content as Hv0.5 (kg mm−2) = 31.12 + 13.23 Y (at.%). The yield strength increases linearly with cn, where c is the solute atom concentration and n = 1/2 or 2/3. However, the yield strength deviates from the cn power-law at temperature over 100 °C. This deviation observed in tensile tests over a temperature range 150–250 °C can be correlated with the dynamic strain ageing (DSA) effects due to the interaction between dislocations and solute Y atoms, which is evidenced by the serrated flow, as well as the local minimum and plateau in the temperature dependences of yield and ultimate strength. Other possible strengthening mechanisms have been also discussed.