Seminars and Events

Planar faults energies in multicomponent Co-base superalloys

Date/Time: 16.09.2014. 4:00 p.m.
Place: Ruhr-Universität Bochum, Bochum, Germany

Alessandro Mottura, University of Birmingham, Birmingham, United Kingdom

Creep deformation mechanisms markedly change with chemistry in the superalloys. The planar faults observed after creep in Co-based superalloys are dramatically different to the planar faults observed after creep in Ni-based superalloys. This happens, in part, due to the effect of chemistry on planar fault energies. In this work, using a variety of modeling methods, the variation of planar fault energies across wide compositional ranges in multi-component Co-based alloys is investigated. Results are discussed in light of high-resolution energy dispersive spectroscopy and high-resolution scanning transmission electron microscopy results showing segregation of elements such as Ta and W to the superlattice intrinsic stacking faults. Although Ta additions may produce an increase in stacking fault energies, the presence of other solute elements can lead to synergetic effects, which instead minimize the value of stacking fault energies.

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