On the role of γ particles within γ′ precipitates on damage accumulation in the P/M nickel-base superalloy N18

The contribution of intergranular γ′ precipitates on the damage accumulation of the powder metallurgy superalloy N18 has been investigated. Electron microscopy investigations tend to link the deformation of primary precipitates to γ particles forming within primary γ′ precipitates. Indeed, these fine ductile particles can act as dislocation sources. The plasticity of primary precipitates is, thus, assisted by the presence of γ particles and deformation incompatibilities are consequently increased at γ/γ′ interfaces.