Seminars and Events

Partitioning and sublattice preference of alloying additions in Co-Co3W system

Date/Time: 16.09.2014. 4:45 p.m.
Place: Ruhr-Universität Bochum, Bochum, Germany

Sri Raghunath Joshi, Department of Materials Engineering, Indian Institute of Science Bangalore, Bangalore, India

Recent interest in Co-base superalloys has been due to the discovery of cubic L1 2 precipitates in the Co-Al-W system. However, the γ+γ' phase field is stable only over a narrow range of compositions and thus there is a need for exploring alternative alloy systems. This study was aimed at probing the role of alloying on stability of Co3W precipitates via electronic structure calculations based on density functional theory. Ground-state energies and lattice parameters were computed for fcc Co and Co3W (in L12 and D019 structures) alloyed with X = Mn, Fe, Ni, Pt, Cr, Al, Si, V, W, Ta, Ti, Nb, Hf, Zr and Mo. In the ordered structures,these alloying elements were substituted into both sublattices. The aim was to evaluate the preference of X for the Co sublattice in L12 and D019, W sublattice in L12 and D019 and fcc Co solid solution. Results suggest that alloy partitioning derived from sublattice preference can be used for designing novel alloy compositions with dual phase microstructure.

« back