A Comparison Study of Electrical Resistivity, Vickers Hardness, and Microstructures of Alloy 625 Prior and Posterior to Rolling

Abstract

Electrical resistivity and Vickers hardness of Alloy 625 due to cold rolling were measured, and, discussed with the microstructural change obtained using electron backscattered diffraction and X-ray diffraction. Both increase in dislocation density and grain subdivision due to rolling was observed. Although the electrical resistivity of the normal pure metals increases with increasing the rolling reduction, that of Alloy 625 initially decreased with increasing the rolling reduction of 70％. Then, the electrical resistivity slightly increased with increasing the rolling reduction of 80％. Up to the rolling reduction of 70％, the reduction of electrical resistivity is associated with K effect, which is the destroy of the short-range ordered domain due to the plastic deformation. On the other hand, Vickers hardness increased with increasing the rolling reduction. It was associated with the contribution of grain refinement, dislocation, solid solution, and sort-range order strengthening.

Fig. 6　Electrical resistivity of Alloy625 measured at 77 K and 293 K depending on rolling reduction.