Effect Of Y Addition On Microstructure And Mechanical Properties Of As-Cast MG-ZN-ZR-LA Magnesium Alloys
The microstructure and mechanical properties of as-cast Mg-Zn-Zr-La-Y alloys were investigated. The alloys were produced by low pressure die casting method. Microstructure investigations revealed that Y addition resulted in a formation of Mg-Zn-Y phases generally expressed as three forms I-phase (Mg3Zn6Y), W-phase (Mg3Zn3Y2) and X-phase (Mg12ZnY). After Y addition, the coarse Mg-Zn-La second phases were replaced by semi-continuous net-like second phase structure, which coarsened with increasing Y addition. A considerable increase in the yield strength was observed after Y addition but elongation to fracture was deteriorated due to the increased amount of second phases that may cause premature crack propagation.
Keywords: Magnesium Alloy, ZK60, Casting, Microstructure, MechanicalProperties.