Effect of High-Energy Ball-Milling Duration on Densification, Microstructure, and Mechanical Properties of Cr2AlC-Dispersed 90W-6Ni-2Fe-2Co Heavy Alloys

Abstract

This study focuses on the role of Cr2AlC-MAX phase incorporation on the density, phase composition, microstructure, and mechanical properties of 90W-6Ni-2Fe-2Co heavy alloy. The blended powders are ball milled in a high-energy ball mill up to 40 h, compacted, and sintered at 1500 degrees C. The mechanical alloying results in a refined microstructure with uniform distribution of W, matrix, and dispersoids. The minimum grain size of W (14.7 +/- 5.6 mu m) is obtained in 2 wt% Cr2AlC-containing tungsten alloy prepared from 40 h-milled powders. Among the investigated alloys, 1 wt% Cr2AlC-incorporated samples exhibit maximum compressive stress (2026 MPa). The incorporation of fine Cr2AlC as dispersoids is found to be beneficial in improving the strength as well as ductility of WHAs. The best combination of yield strength (553.4 MPa), ultimate tensile strength (1011.2 MPa), ductility (11.4%), and product of strength and elongation (11.5 GPa%) is found in alloy prepared from 40 h milled 90W-4.8Ni-1.6Fe-1.6Co-2Cr(2)AlC. The improved tensile strength in Cr2AlC-incorporated WHAs may be attributed to the combined effect of grain size refinement and dispersion strengthening. Overall, the combination of ball milling and Cr2AlC incorporation in tungsten-heavy alloys is found to be effective in developing a novel W-based alloy system for strategic applications.