Equilibrium phases and transformations in Fe/Co/2--3%V alloys

A study was conducted to determine the boundaries of the two-phase field in Remendur alloys. Quantitative determination of the phase boundaries at 900 to 9500C shows the two-phase α1 + γ field to be narrower than expected from published data. Annealed microstructures are especially sensitive to vanadium content, annealing temperature, and annealing time and, therefore, commercial procedures must be carefully controlled. Rotation of tie-lines in the α1 + γ field indicate that the γ phase becomes increasingly rich in vanadium and cobalt with decreasing temperature. Upon quenching from the 900 to 9500C range the γ(fcc) phase undergoes a massive type transformation to a nonequilibrium α2(bcc) phase. During subsequent annealing at 6000C the α2 phase decomposes into α1' (ordered bcc) and stable γ. Even after an extended anneal the stable γ particles are too small for quantitative microprobe analysis. (U.S.)