Strengthening of Inconel 600 alloy with electric current stressing

The Inconel 600 alloy was investigated for the possibility of monitoring mechanical property, Vickers hardness, with electric current stressing. A parameter tD/N combined of current stressing duration tD and current stressing cycle N was applied as the control factor. With the appropriate control of the combined parameter and current stressing density of 7 × 103 A/cm2, a maximum enhancement of microhardness by 19.5% comparing with heat treated benchmark specimen was achieved. The study investigated the strengthening mechanism from various aspects including grain orientation, grain size, phase transformation, precipitation, and dislocation with EBSD, XRD, and HRTEM. A maximum dislocation density of 5 × 1016 m−2 in the 111 direction was obtained at ln(tD/N) of -0.69. The microhardness enhancement was ascribed to strain hardening by dislocation formation upon current stressing.