A high performance Mg–Al–Ca alloy processed by high pressure die casting: Microstructure, mechanical properties and thermal conductivity.

The demand for high-performance magnesium alloys, including high strength, high thermal conductivity, and good heat resistance, is growing rapidly in practical applications. Here, we report a high performance Mg–7Al–3Ca (AX73, wt.%) alloy with high strength, good thermal conductivity, and acceptable heat resistance via the high-pressure die casting (HPDC) method. Compared to the commonly used Mg–4Al–4RE (AE44) and Mg–9Al–1Zn–0.25Mn (AZ91D), the HPDC AX73 exhibited a much higher yield strength (YS) at room temperature (RT) and 175 °C. The high YS was attributed to the combinations of fine-grain strengthening, second phase strengthening from numerous Al 2 Ca eutectic phases, and solid solution strengthening from Al solutes. After the aging treatment, the room-temperature YS of AX73 alloy was further improved from 184 MPa to 196 MPa due to fine Al 2 Ca precipitation. Since the existence of Ca obviously reduced the Al solutes in the α-Mg matrix, the AX73 and AX73 aged alloys possessed reasonable thermal conductivity of 67 and 68.5 W(m·K)−1, respectively. [Display omitted] • A high-performance Mg–7Al–3Ca (AX73) was fabricated by the high-pressure die casting (HPDC) method. • The HPDC AX73 exhibited a much higher yield strength (YS) at room temperature and 175 °C. • The aging treatment further improved the YS due to fine Al 2 Ca precipitation. • The AX73 and AX73 aged alloys possessed reasonable thermal conductivity of 67 and 68.5 W(m·K)−1, respectively. [ABSTRACT FROM AUTHOR]