Microstructures and Thermal Properties of Mg-Sn-Ca Alloys: Casts and Extrusions

Microstructure and thermal properties of Mg-(3 mass% or 5 mass%) Sn-2 mass% Ca alloys as casts and extrusions have been investigated with different ram speeds and extrusion temperatures. Mg-(3 mass% or 5 mass%) Sn-2 mass% Ca alloys are composed of -Mg, MgSnCa, and phases. By adding Sn content from 3 mass% to 5 mass%, the MgSnCa phase is increased and the phase is decreased. During hot extrusion, the average grain sizes are increased with increasing ram speed and temperature. The ultimate tensile strength (UTS) and elongation for the Mg-5Sn-2Ca alloy at are 227.73 MPa and 18.43 %, respectively. With increasing extrusion ram speed, the UTS and elongation for the Mg-5Sn-2Ca alloy are remarkably decreased to 215.95 MPa, 206.33 MPa, and 14.74 %, 6.88 %, respectively. The thermal conductivity for the Mg-3Sn-2Ca alloy is dramatically improved, compared to commercialized Mg alloys such as AZ31 and AZ91 due to formation of MgSnCa and phases.