Preparation of Mg-Nd alloys by in situ reduction using Nd2O3

The high cost of producing magnesium alloys containing rare earth with Mg-RE master alloy severely restricts the wide application of rare earth in magnesium alloys. Consequently, we have adopted a novel, cost-effective approach to preparing magnesium alloys containing rare earth elements by calcium thermal reduction of RE₂O₃. This paper presents the successful preparation of neodymium-containing magnesium alloy by the method described, with the process parameters optimized by orthogonal test and single-factor experiment. The optimum process parameters are 780℃ melting point, 1/6 content ratio of Ca to Nd ₂O ₃, and 90 min reaction time. The results of SN ratios and ANOVA showed that time had the greatest effect on Nd yield, the content ratio of Ca and Nd ₂O ₃ followed, and temperature had the least effect on Nd yield. The actual Nd yield of the optimal alloy is 32.67 %, which is in the range of Taguchi`s prediction of 23.36–33.83 %. Based on orthogonal experiments, the relationship between the three factors and Nd yield was studied separately and in detail. The results show that the Nd yield exhibits a trend of initial increase and subsequent decline as a function of reaction time, content ratio of Ca to Nd2O3, and melting temperature. The Nd yield peaked at a reaction time of 90 min, a content ratio of Ca to Nd ₂O ₃ of 1/6 and a melting temperature of 780 ℃. A physical phase analysis and microstructure observation of the alloys prepared with the optimal process parameters were conducted. The alloy is comprised primarily of three distinct phases: α-Mg, Mg ₂Ca, and Mg ₄₁Nd ₅. This proves that Mg-Nd alloy can be prepared successfully by this method, and provides a new idea for the preparation of magnesium alloys containing rare earth.