Microstructure and mechanical properties of Mg-6Al-4RE-0.4Mn alloy
(1.Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry,Chinese Academy of Sciences, Changchun 130022, China
2.吉林省长春市中科院长春应用化学研究所稀土化学与物理重点实验室)
2.吉林省长春市中科院长春应用化学研究所稀土化学与物理重点实验室)
Abstract: Mg-6Al-4RE-0.4Mn (mass fraction, %, RE=Ce rich mischmetal) alloy was prepared by steel mould casting technique. Solid solution and artificial aging (T6) were carried out. The microstructure and mechanical properties of both as-cast and T6 treated alloys were investigated at room temperature and 423 K. It is found that the intermetallic compounds of the as-cast and T6 treated alloys were mainly composed of Al11RE3, Mg17Al12 and Al6REMn6. The Vickers hardness (Hv) of the as-cast alloy is 63 and it increases to 70 after T6 heat treatment. T6 heat treatment plays a slight role in the tensile properties at room temperature, but the yield strength and elongation of T6 state at 423 K are distinctly improved. The yield strength and elongation of the as-cast alloy at 423 K are 71 MPa and 18%, respectively, and the values increase after T6 heat treatment, which is attributed to Al11RE3, Mg17Al12 and Al6REMn6 precipitates that impede the dislocation movement and gliding of grain boundaries effectively.
Key words: Mg-Al-RE alloy; casting; heat treatment; microstructure; mechanical property