Abstract:The effects of rare earth(RE) elements Y and Nd (w(Y)/w(Nd)=3׃2) with total content of 1%−4% on microstructures and elevated temperature mechanical properties of AZ81 magnesium alloy were investigated. The results show that, proper content of rare earth elements makes the microstructures of AZ81 magnesium alloy refine obviously and the quantity of β-Mg17Al12 phases reduce, and Al2Y and Al2Nd form. After solid solution treatment, with increasing content of rare earth elements, the tensile strength and elongation of the alloys (at room temperature, 150 ℃ and 250 ℃) increase first, then decrease. When the content of rare earth elements is up to 2%, the values of tensile strength at room temperature and 150 ℃ are up to their maxima simultaneously, 282 MPa and 212 MPa, respectively. Meanwhile, the values of elongation at room temperature and at elevated temperature are also up to their maxima, 13% and 15%, respectively.

Key words: AZ81 magnesium alloy; rare earth; yttrium; neodymium; microstructure; mechanical properties