Using lanthanum to enhance the overall ignition, hardness, tensile and compressive strengths of Mg-0.5Zr alloy

Abstract

Near dense Mg 0.5 wt.% Zr (0, 1, 2.5 and 4) wt.% La alloys were successfully synthesized by disintegrated melt deposition technique followed by hot extrusion and were characterized for their microstructural, ignition, hardness, tensile and compression properties. Combined effects of Zr and La assisted in significant grain refinement of Mg and Mg 0.5 wt.% Zr 4 wt.% La exhibited an average grain size as low as ∼2.75 µm. High ignition temperature of ∼645 °C was realized with Mg 0.5 wt.% Zr (1, 2.5 and 4) wt.% La alloys. Microhardness value as high as ∼103 Hv was observed with Mg 0.5 wt.% Zr 4 wt.% La alloy. Under room temperature tensile and compression loading, significant improvements in the strength properties of pure Mg with the addition of 0.5 wt.% Zr (0, 1, 2.5 and 4) wt.% La was observed. Mg 0.5 wt.% Zr 4 wt.% La exhibited the maximum 0.2% tensile and compression yield strengths of ∼283 MPa and ∼264 MPa, respectively. The tensile and compression fracture strain values of synthesized pure Mg were found to be unaffected with the addition of 0.5 wt.% Zr. But the tensile fracture strain reduced with the addition of La while the compressive fracture strain was unaffected. Minimal tensile-compression asymmetry (∼1) was exhibited by Mg 0.5 wt.% Zr (1 and 2.5) wt.% La alloys.