The Influence of Holmium on the Microstructure and Hardness of Mg-Nd-Gd-Zn-Zr Alloys
The influence of holmium on the microstructure and hardness of Mg-Nd-Gd-Zn-Zr alloys were investigated. Conventional casting methods are used to produce the alloys. All the results were characterized by optical microscopy, scanning electron microscope (SEM) and the Vickers hardness test to highlight the influence of holmium addition. The addition of 2.0 wt.% holmium leads to the combination of rare earth elements which formed Mg-Zn-Nd-Ho phase. The results have shown the addition of Ho improved the microstructure and hardness of Mg-Nd-Gd-Zn-Zr alloys. By adding grain size of 2.0 wt.% holmium had reduced by 18.43%, while the volume fraction increased by 7.34%. The Vickers hardness value improved 6.18% due to the grain refine and volume fraction precipitates. The 2.0 wt.% holmium addition showed a positive result in microstructure and hardness value.
R. Ahmad et al., "The Influence of Holmium on the Microstructure and Hardness of Mg-Nd-Gd-Zn-Zr Alloys", Key Engineering Materials, Vol. 740, pp. 48-53, 2017