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 $$\upalpha $$ -Mg, MgSnCa, and $$\hbox {Mg}_{2}\hbox {Ca}$$ phases. By adding Sn content from 3 mass% to 5 mass%, the MgSnCa phase is increased and the $$\hbox {Mg}_{2}\hbox {Ca}$$ 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 $$2.3\, \hbox {mm}{\cdot }\hbox {s}^{-1}$$ 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 $$\hbox {Mg}_{2}\hbox {Ca}$$ phases.