The ternary systems: Cr [sbnd]Al [sbnd]C, V [sbnd]Al [sbnd]C, and Ti [sbnd]Al [sbnd]C and the behavior of H-phases ( M 2AlC )

Abstract

Phase relationships in the ternary systems Cr Al C, V Al C, and Ti Al C have been investigated. All previously reported ternary H-phase Me 2AlC(Me =Cr, V, Ti) and the perovskite phase Ti 3AlC are confirmed. No new ternary phase was found. At 1000°C Ti 2AlC and Ti 3AlC are coexistent. In addition, the H-phase was found in equilibrium with TiC 1− x , TiAl 3, and TiAl; the perovskite with TiC 1− x , Ti 3Al, and Ti (solid solution with Al). TiC 1− x coexists with Al(l) at temperatures above 800°C. V 2AlC coexists at 1000°C with Al 4C 3, Al(1), Al 3V, V 7Al 8, V (solid solution with Al), V 2C, ζ-VC 1− x , and VC 1− x (including V 8C 7). At 1000°C Cr 2AlC is in equilibrium with Al 4C 3, γ-Cr 5Al 8, Cr (solid solution with Al), Cr 7C 3, and Cr 3C 2. At 800°C Cr 2AlC coexists also with graphite and β-Cr 2Al. V 2AlC forms a complete series of solid solutions with Cr 2AlC and Ti 2AlC. At about 1000°C the solid solution series Ti 2AlC Cr 2AlC exhibits a miscibility gap.