High-gravity combustion synthesis of W-Cr alloys with improved hardness

•A new method of high-gravity combustion synthesis to prepare W-Cr alloys.•The W-Cr alloys show a hierarchical microstructure.•The hardness of the W-Cr alloys reaches 11.2 GPa.

W-Cr alloys have been prepared by high-gravity combustion synthesis from aluminothermic reactions. The alloy with the composition of W0.5Cr0.5 shows a hierarchical microstructure composed of both micro- and nano-sized grains, which is proposed to be produced by spinodal decomposition. The hierarchical microstructure contributes to an improved hardness of 11.2 GPa, which almost doubles that of the W0.5Cr0.5 alloy prepared by sintering. Compared with the conventional powder metallurgy approach, high-gravity combustion synthesis may offer a more efficient way to produce W-Cr alloys with much reduced time and energy consumption.