Dual-phase synergistically enhancing mechanical properties and thermal conductivity of hot-extruded Mg-8Gd-1Er-8Zn-1Mn alloy

The contradiction between mechanical properties and thermal conductivity of magnesium alloys is a roadblock for their widespread applications. In this study, we developed a hot-extruded Mg-8Gd-1Er-8Zn-1Mn alloy with high-strength and high-thermal-conductivity via dual-phase, W-phase and α-Mn, synergistically strengthening. The alloy extruded at 300°C exhibited the yield strength and elongation of 372 MPa and 12 %, respectively, it simultaneously demonstrated a high thermal conductivity of 134.3W/(m·K). After extrusion, the original coarse W-phase in the alloy was broken into near-spheroidal particles, which reduced the probability of electron scattering. In addition, a large number of solute atoms dynamically precipitated in the form of nanoscale rod-like W-phase and α-Mn, making α-Mg matrix revert to a nearly periodic arrangement state. The high yield strength of the alloy is predominantly determined by grain boundary strengthening as well as W-phase and α-Mn dual-phase strengthening. Notably, the strategy of dual-phase strengthening provides a valuable approach for developing structure-function integrated Mg alloys.