Necking contributions to σ-phase formation in a hot-corrosion-resistant superalloy during creep exposure

► Necking phenomenon occurs in strained-to-fractured specimens after creep exposure. ► The σ-phase density decreases from fracture face to the end of the gauge section. ► The shape, size, and composition of the σ phase are not affected by necking. ► Stress accelerates the formation of the σ phase during exposure. ► These phenomena are mainly due to the variation of strain energies.