LAUSR

Abstract In present paper, Zircaloy-4 surface alloying with copper (Cu) using a high-current pulsed electron beam (HCPEB) device was firstly studied. For investigating the changes in microstructures and corrosion resistance prior and after surface alloying, a series of characterization methods were adopted. Results revealed that, after surface alloying by HCPEB, a Cu-riched alloying layer with a thickness of about 3 μm was formed within the melted layer, inside which martensitic transformation was largely inhibited and large numbers of ultra-fine equiaxed β grains were generated. Most of the Cu elements in the alloying layer were uniformly distributed in the β-Zr supersaturated solid solution, others were existed in the form of fine dispersed ZrCu SPPs. Besides, Zr(Fe,Cr)2 SPPs were dissolved into the Zr-matrix within the HCPEB affect area. Compared with initial and directly irradiated specimens, the specimen after surface alloying exhibited extremely excellent anti-corrosion performance at 500 °C/10.3 MPa superheated steam, which was mainly attributed to those supersaturated Cu elements.