Development of Microstructures and Mechanical Properties in Differential Speed Rolled Ni-30Cr Alloy

Abstract

We evaluated the developed microstructures and mechanical properties of a severely plastically deformed Ni-30Cr alloy. Normal rolling and differential speed rolling were used as deformation processes, and the thicknesses of the specimens were reduced to 68 % of the original thickness after holding at for 10 min and annealing at for 40 min to obtain a fully recrystallized microstructure. Electron backscattering diffraction was used to analyze the characteristic distribution of the grain boundaries on the deformed and annealed specimens. Differential speed rolling was more effective for refining grains in comparison with normal rolling. The grain size was refined from 33 mm in the initial material to 8.1 mm with normal rolling and 5.5 mm with differential speed rolling. The more refined grain in the differential-speed-rolled material directly resulted in increases in the yield and tensile strengths by 68 % and 9.0%, respectively, compared to normal rolling. We systematically explain the relationship between the grain refinement and mechanical properties through a plastically deformed Ni-30Cr alloy based on the development of a deformation texture. The results of our study show that the DSR process is very effective when used to enhance the mechanical properties of a material through grain refinement.