2013 年 54 巻 625 号 p. 143-147
The AZX (X = calcium) series of magnesium alloys have recently been developed as lightweight incombustible alloys for use in automotive and railway vehicles. However, magnesium alloys containing Ca show inferior plastic deformation and poor formability. The tensile properties of rolled and annealed samples of Mg-3Al-1Zn-1Ca (AZX311) alloy were examined. Sheets of this alloy subjected to a rolling process of three passes at 473 K without reheating showed a 0.2% proof stress of 361 MPa and a tensile strength of 373 MPa. The high strength of the AZX311 alloy sheet was the result of the effective grinding of compounds and their fine dispersal in the magnesium phases, which occurred during rolling deformation and grain refinement. After annealing, the growth of compounds and grains was improved without extreme elongation, but the strength of the compounds was maintained owing to their fine dispersion. The thermal stability of this alloy was improved by adding only 1 mass% elemental Ca.