Quasi-gradient variation of microstructures and properties of Cu–Sn alloy along the thickness direction under cold spinning

Abstract During cold spinning, the grain size, grain boundary angle and tensile strength of Cu– Sn alloy show quasi gradient changes in the thickness direction (TD) of hollow cylinder. According to a mechanical analysis, electron backscattering diffraction observations (EBSD), and a finite element simulation, the grain size of Cu–Sn alloy after spinning increases from the outer surface to the inner surface. The number of ultrafine grains was largest on the outer surface, and the original grain boundaries were retained on the inner surface. All of the grain orientations from the outer surface to the inner surface were randomly distributed. An analysis of the grain misorientation suggested that low-angle grain boundaries (LAGBs; 10°) was inversely proportional to that of LAGBs, the grain boundary energy (GBE) of the HAGBs decreased with increasing number of LAGBs, and the number of HAGBs also decreased gradually. According to tensile tests at room temperature, the outer surface exhibited the highest ultimate tensile strength and the inner surface exhibited the greatest plasticity.