Metastable phases in the Co-W system traced from elemental Co and W powders

X-ray diffraction technique was used to identify the phases of the milled and annealed elemental Co, W and Co-W powder mixture. Structural similarities in metastable phases of elemental Co and W have been obtained. The η-phase with 11.037 Å was detected in both milled and annealed W as well as in the Co-W alloy. In addition, metastable FCC Co (W) solid solution of 3.544 Å was detected. Upon annealing a 30 h milled Co powder compact at 800 °C, two metastable FCC phases with lattice parameters of 3.506 Å and 4.162 Å were obtained. For milled, annealed and water-quenched W at 1000 °C, metastable FCC phases with a = 3.510 Å and 4.177 Å were obtained. Furthermore, metastable HCP phase with a = 2.731 Å; c = 4.319 Å was detected after annealing of milled W at 1000 °C.