METASTABLE BCC PHASE-FORMATION IN THE NB-CR SYSTEM

Extended metastable b.c.c. solid solutions of Nb-Xat.%Cr (X= 35, 50, 5 7, 77, 82 and 94) were synthesized by two-anvil splat-quenching. In ad dition, b.c.c. Nb-67at.%Cr was prepared by mechanically alloying mixtu res of niobium and chromium powders. The lattice parameters were measu red by X-rav diffraction and the Young's moduli by low load micro-inde ntation. The composition dependence of the lattice parameters and elas tic moduli shows a positive deviation with respect to a rule of mixtur es. During continuous heating at 15-degrees-C min-1, the metastable pr ecursor b.c.c. phases decomposed at temperatures above 750-degrees-C t o uniformly refined microstructures.