MATERIALS RESEARCH EXPRESS, cilt.6, 2019 (SCI İndekslerine Giren Dergi)
The microstructure, mechanical and wear properties of as-cast and as-extruded Mg-6Zn-0.5Zr (wt%) alloys, also denoted as ZK60, containing minor Nd additions by 0.2 and 0.5 wt% were investigated. The alloys were produced by low pressure die casting (LPDC) method and extruded at 300 degrees C with an extrusion ratio of 16:1 and a ram speed of 0.3 mm s(-1) following homogenization at 400 degrees C for 24 h. Microstructural characterizations revealed that minor Nd addition gave rise to a significant grain refining effect and a formation of divorced, globular and strip-like Mg-Zn-Nd ternary phases. After homogenization, most of the second phases were dissolved in a-Mg matrix and extrusion resulted in a considerable grain refinement. Basal texture intensity of the as-extruded ZK60 alloy dramatically decreased by 0.2 wt% Nd addition. The ultimate tensile strength and elongation-to-fracture of ZK60 alloy were improved by 20% and 40%, respectively, after 0.2 wt% Nd addition in the as-cast state while only elongation-to-fracture was considerably improved by 50% after 0.2 wt% Nd addition in as-extruded state due to the significant texture softening. Wear resistance of the as-cast ZK60 alloy was improved after extrusion and gradually enhanced with increasing Nd content. The abrasion, oxidation and adhesion mechanisms were observed in the alloys.