First-Principles Study of Phase Stability and Mechanical Property of Co_3(Al,W) Precipitates with Different Ratio of Al to W in Co Base Alloys

摘要

The energetics, electronic structure and mechanical property of Co_3(Al,W) precipitates with different ratio of Al to W in Co base alloys were investigated by the method of supercell and augmented plane waves plus local orbitals within generalized gradient approximation. The calculated results show that the L1_2 Co_3(Al,W) precipitate is the most stable when the ratio of Al to W is equal to 1. When the content of W is higher than 18.5 at%, the L12 and hexagonal structures co-exist in Co_3(Al,W) precipitates at 1173 K. It is also shown that the L12 ordered Co_3(Al,W) precipitates have an obvious strengthening effect in the disordered fcc cobalt matrix.

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