Effects of Al concentration and Zn addition on microstructures and mechanical properties of Mg–Al–(Zn)–Ca series magnesium (Mg) alloy medium plates were investigated. Concerning to mechanical properties of AMX (Mg–Al–Ca) alloys with various Al concentrations, which were processed by rolling at 523 K and final annealing at 473 K, good balance of tensile strength and failure elongation were obtained, when Al concentration was 8 mass%. When Al concentration was more than 9 mass%, however, both tensile strength and failure elongation were deteriorated due to coarsening of Al–Ca compounds. Concerning to mechanical properties of AZX (Mg–Al–Zn–Ca) alloys with various Al concentrations and 1 mass% Zn addition, which were processed by the same procedure with AMX alloys, enhancement of tensile strength without deterioration of failure elongation was attained at Al concentration of 6–8 mass%, when the tensile direction was parallel to the rolling direction. Clear deterioration in failure elongation compared with AMX alloys were observed, however, when the tensile direction was perpendicular to the rolling direction. 1 mass%Zn addition to AMX alloy promoted precipitation of fine Mg
17Al
12 particles, which likely affected mechanical properties. In addition, solid solution of Zn in AMX alloy likely contributed to enhancement of tensile strength.
View full abstract