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First principles study of structural stability and site preference in Co-3 (W,X)

Joshi, Sri Raghunath and Vamsi, KV and Karthikeyan, S (2014) First principles study of structural stability and site preference in Co-3 (W,X). In: 2nd European Symposium on Superalloys and their Applications, MAY 12-16, 2014, Giens, FRANCE.

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Official URL: http://dx.doi.org/10.1051/matecconf/20141418001

Abstract

Since the discovery 1] of gamma' precipitate (L1(2) - Co-3 (Al, W)) in the Co-Al-W ternary system, there has been an increased interest in Co-based superalloys. Since these alloys have two phase microstructures (gamma + gamma') similar to Ni-based superalloys 2], they are viable candidates in high temperature applications, particularly in land-based turbines. The role of alloying on stability of the gamma' phase has been an active area of research. In this study, electronic structure calculations were done to probe the effect of alloying in Co3W with L1(2) structure. Compositions of type Co-3(W, X), (where X/Y = Mn, Fe, Ni, Pt, Cr, Al, Si, V, W, Ta, Ti, Nb, Hf, Zr and Mo) were studied. Effect of alloying on equilibrium lattice parameters and ground state energies was used to calculate Vegard's coefficients and site preference related data. The effect of alloying on the stability of the L1(2) structure vis a vis other geometrically close packed ordered structures was also studied for a range of Co3X compounds. Results suggest that the penchant of element for the W sublattice can be predicted by comparing heats of formation of Co3X in different structures.

Item Type: Conference Proceedings
Additional Information: 2nd European Symposium on Superalloys and their Applications, Giens, FRANCE, MAY 12-16, 2014
Keywords: HIGH-TEMPERATURE ALLOYS; AUGMENTED-WAVE METHOD;1ST-PRINCIPLES; DEFORMATION; METALS
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 29 Apr 2015 05:48
Last Modified: 29 Apr 2015 05:48
URI: http://eprints.iisc.ac.in/id/eprint/51461

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