Effect of Ca Addition to the Elevated Temperature Mechanical Properties of AZ Series Magnesium Alloys

In this study, in order to investigate the effect of Ca addition on elevated temperature mechanical properties of AZ series magnesium alloys, 3 different alloys (AZ21, AZX211, and AZX311) were produced. Elemental and phase analyses along with microstructural characterization were performed by using XRF, XRD, optical microscope, and SEM-EDS. Tensile and wear tests were conducted at 25 °C, 150 °C, and 200 °C for the purpose of revealing the room and elevated temperature service condition performances of the alloys which were followed by the application of hardness measurement applied at 25 °C to the alloys. It was observed that while the microstructure of AZ21 alloy contained only α-Mg, the microstructures of AZX211 and AZX311 alloys contained α-Mg, (Mg, Al)2Ca and Al2Ca due to the addition of Ca. Furthermore, the strengths of AZX211 alloy were better for all temperatures, especially at 25 °C with 152 ± 5.4 MPa tensile strength and 95 ± 4.1 MPa yield strength, and also it had the lowest hardness (51.6 ± 1.3 HV) as compared to the other alloys. When all temperatures wear rates were compared, the AZX211 alloy was understood to have a stable wear rate for all applied load values, especially under 40 N applied load for 22.826 ± 0.730 × 10−3 mm3/m at 25 °C, 21.201 ± 0.758 × 10−3 mm3/m at 150 °C and 24.768 ± 0.326 × 10−3 mm3/m at 200 °C test temperatures, respectively.