Microstructural Characterization of as-Cast and Cold Deformed Precipitation Strengthened Cu-3Ti-3Ni-0.5Si Alloy

Abstract

In this work, the microstructure and recrystallization behavior of Cu-3Ti-3Ni-0.5Si alloy after thermomechanical processing were investigated by light microscope (LM), scanning electron microscope (SEM), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM). The results show that the as-cast Cu-3Ti-3Ni-0.5Si alloy consists of NiTi, Ni3Si, Ni2Si phases and Cu matrix, and the phase transformation occurs twice during the cooling process. Moreover, with increase of aging temperature, the precipitates in the Cu-3Ti-3Ni-0.5Si alloy matrix changes from rod-liked morphology to spherical shape, and the sizes and volume fraction of the spherical precipitates increase progressively. Furthermore, the number of the recrystallization grain increases with increase of the aging temperature, thus leading to decrease on the grain size. In addition, the fraction of low angle grain boundaries decreases, whereas the fraction of high angle grain boundary increases with increase of aging temperature