The effect of high-current pulsed electron beam on phase formation and surface properties of chromium/copper system

Abstract In this paper, high-current pulsed electron beam (HCPEB) irradiation was used as surface alloying of chromium/copper (Cr/Cu) system to improve the surface hardness and corrosion resistance. After surface alloying, an alloying layer with a spot of craters and plentiful crystal defects (eg. dislocation walls and cells) was prepared on the surface of sample. The existence of crystal defects induced by HCPEB irradiation offered a mass of diffused channels for Cr atoms to facilitate the formation of Cu (Cr) solid solution. Subsequently, partial solid solutions were decomposed to generate GP zone, lobe-shaped particles and spherical particles, which had the characteristic of relationship Nishiyama-Wassermann (N-W) and Kurdjumov-Sachs (K-S) orientation relationship with the Cu matrix. These features account for that surface hardening of Cr alloyed sample was significantly higher than that of W alloyed samples. The corrosion performance of the Cr-alloyed sample exhibited much stable corrosion resistance comparing with that of W-alloyed samples. The enhancement of passivation property was mainly resulted from the formation of more stable passive film, which was associated with the existence of the crystal defects and the alloying particles.