Microstructure refinement and high-temperature tensile properties of Mg-12Gd-3Y-0.5Zr alloy after equal channel angular pressing

Grain refinement is significant for the mechanical properties of engineering alloys. We achieved a bi-ultrafine microstructure in an Mg-12Gd-3Y-0.5Zr alloy through equal channel angular pressing (ECAP) at 300 degrees C. The ECAP not only refined the matrix grains but also broke the large intermetallic particles into fine secondary particles and then rearranged them at the grain boundaries. These fine particles can suppress the growth of the recrystallised grains, as well as promote nucleation for recrystallisation. After four passes of ECAP, a uniform microstructure with both the matrix grain (similar to 500 nm) and the particle size (similar to 300 nm) in the ultrafine range was obtained. This unique microstructure resulted in a good combination of strength (>300MPa) and elongation to failure (>35%) at 200 degrees C, which sheds new light on refining microstructure to obtain good mechanical performance at elevated temperatures for Mg alloys.

Automated summary

Grain refinement and intermetallic particle fragmentation achieved through ECAP led to a unique microstructure with improved mechanical properties in the Mg-12Gd-3Y-0.5Zr alloy, showing high strength and elongation to failure at elevated temperatures.