Microstructure and mechanical properties of cast Mg-15Al-xNd alloy by permanent mold

To improve the comprehensive mechanical properties of Mg-15AI magnesium alloy, different amounts （from 0 to 4.0wt.%） of Nd were added to the alloy and six Mg-15AI-xNd alloys were prepared by metal mould casting. The effect of Nd content on microstructure of the alloys was investigated by means of OM, SEM, EDS, TEM, and XRD. The tensile properties were tested at room temperature （RT） and high temperature （473 K）. The results indicate that the primary a-Mg dendrite is significantly refined with the addition of Nd. The best refinement is reached at 1.0wt.% Nd content and the average dendrite arm spacing decreases from 80- 100 pm （without Nd addition） to -20 pm. A further increase in Nd content leads to the coarsening of the primary a-Mg dendrite. The addition of Nd improves the tensile properties of Mg-15AI both at RT and 473 K. The Mg-15AI alloy containing 1.0wt.% Nd exhibits the best tensile properties. Compared with the alloy without Nd, the yield and ultimate tensile strength of the Mg-15AI-1.0Nd alloy at RT increase from 132.3 to 148.6 MPa and 152.3 to 189.6 MPa, increase by 12.3% and 24.5%, respectively; and the elongation at RT increases from 0.05 % to 1.24%. The yield and tensile strength of the alloy at 473 K increase from 97.9 to 115.3 MPa and 121.6 to 140.1 MPa, increase by 15.2% and 20%, respectively. Further increment of Nd content to 1.5wt.% degrades the tensile properties, which is ascribed to grain coarsening and growth of the AI-Nd phase.

Microstructure and mechanical properties of Mg-6Al magnesium alloy with yttrium and neodymium

The effects of rare earth(RE) elements Y and Nd on the microstructure and mechanical properties of Mg-6Al magnesium alloy were investigated.The results show that a proper level of RE elements can obviously ref ine the microstructure of Mg-6Al magnesium alloys,reduce the quantity of β-Mg17Al12 phase and form Al2Y and Al2Nd phases.The combined addition of Y and Nd dramatically enhances the tensile strength of the alloys in the temperature range of 20-175℃.When the content of RE elements is up to 1.8%,the values of tensile strength at room temperature and at 150℃ simultaneously reach their maximum of 253 MPa and 196 MPa,respectively.The main mechanisms of enhancement in the mechanical properties of Mg-6Al alloy with Y and Nd are the grain ref ining strengthening and the dispersion strengthening.

Effects of RE on the Microstructure of Mg-8Zn-4Al Magnesium Alloys

The effects of RE on the microstrcture of as-cast Mg-8Zn-4Al magnesium alloys were investigated. The results show that the solidification range of Mg-8Zn-4Al-xRE alloys increases with RE additions. A binary eutectic reaction can arise and produce a new phase （Mg：Al：Zn：RE） and the temperature of phase transformation point of the new phase is 412.85 C. In Mg-8Zn-4Al-1.5RE alloy, a small amount of Mg：Al：Zn：RE phase and ε phases are found besides a（Mg）,φand r phases. Also microstructures of Mg-8Zn-4Al alloys can be refined by addition of 1.5% RE obviously.