Synergistic effect of Cr2AlC MAX phase incorporation on microstructural parameters and distortion prevention of 90W-6Ni-2Fe-2Co heavy alloys

Abstract

The present work delves with the important contribution of the microstructural and distortion parameters that led to distortion prevention in the Cr2AlC MAX phase-incorporated 90W-6Ni-2Fe-2Co heavy alloys. The powder mix was milled for 20 h and 40 h in a high-energy ball mill. Then, the green compacts of 0 h, 20 h, and 40 h milled powders were sintered at 1500 degrees C in hydrogen atmosphere for 75 min. The FESEM micrographs depicted a uniform distribution of Cr and Al-oxides on the W grain boundaries, which hinders the solution-reprecipitation process during liquid-phase sintering, thereby inhibiting the sintered densification. The distortion parameter (delta\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\delta$$\end{document}) of the as-sintered samples decreased with increased Cr2AlC content, which is one of the main standpoints in preventing shape distortion. The reduction in W grain size was given paramount importance with Cr2AlC addition in accordance with higher milling durations. The EPMA analysis displayed a uniform distribution of W, Ni, Fe, Co, Cr, Al, O, and C in 2 wt% Cr2AlC 20 h, and milled WHAs, which confirms the formation of Cr, Al-oxides. The microstructural parameters such as volume fraction of solid (Vs), contiguity (Css), dihedral angle (phi\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\phi$$\end{document}) and grain connectivity (Cg) were found to be increased in Cr2AlC-incorporated WHAs compared to the base alloy, which has a direct impact on distortion prevention.