The microstructure and mechanical properties of Pb alloying layer on Al using surface alloying by high-current pulsed electron beam

Abstract

In this research, lead (Pb) alloying layer was introduced on the aluminum (Al) substrate to improve the surface properties after surface alloying by high-current pulsed electron beam (HCPEB). The microstructure and phase analysis of the Pb alloying layer was investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The properties of microhardness and wear resistance were also studied. The results show that Pb particles were dissolved into Al substrate and an alloying layer of about 15 µm in thickness was formed after 35-pulsed irradiation. Meanwhile, the refinement and uniform distribution of Pb particles occurred with the increasing number of pulses, as well as the solid solution and structure defects such as dislocation walls and dislocation loops. Besides, some Pb particles exhibited cube-cube orientation relationship with the Al matrix. The surface hardening is mainly owing to the fine grain, dispersion, dislocation and solid solute strengthening. The enhanced wear property is attributed to the improved hardness and the addition of Pb element to form lubricious tribolayer.