Room temperature deformation mechanisms in Nimonic 80A

Abstract The deformation mechanisms occurring during room temperature tensile and low cycle fatigue testing were investigated. During fatigue the ordered γ′ precipitates restricted the dislocation movement to isolated {111} slip planes. The dislocations often moved in pairs as a result of γ′ shearing. Surface grains deformed more homogeneously as indicated by the dislocation cells. A band structure was also observed which resembled persistent slip bands in other age hardened alloys. These bands produced lamellar extrusions on the gauge surface. At higher strain ranges (Δe, > 2%), the strain was also accommodated through micro-twinning and grain rotation. The rotation of the grains produced an asterism in the TEM diffraction patterns which was also observed at higher strains in the tensile specimens.