Research on morphology instability of γ’ precipitates in FGH4096 superalloy
TIAN Gao-feng1，CHEN Yang1，ZOU Jin-wen1，HU Ben-fu2
（1. Science and Technology on Advanced High Temperature Structural Materials Laboratory， Beijing Institute of Aeronautical Materials， Beijing 100095， China 2. School of Materials Science and Engineering， University of Science and Technology Beijing， Beijing 100083， China）
Abstract：Two kinds of γ’ morphology instability during heat treatment process in powder metallurgy nickel-base superalloy FGH4096 were investigated， the instability mechanism and occurrence mode were revealed. The results indicate that the splitting driving force of γ’ precipitates as the reverse coarsening is the release of elastic strain energy， strongly depends on the lattice mismatch and the size of γ’ precipitates， when γ’ particle grows up to a certain size， it needs dissolve itself in order to keep the system energy stable through the release of the elastic strain energy. The unstable protrusion of γ’ precipitates is another morphology instability of γ’ precipitates， which is interfacial instability caused by point diffusion effect when the condition of enough supersaturation in the g matrix is met， determined by concentration gradient effect and surface tension effect.
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2018, Vol. 28 
