Microstructure and properties of friction and weat of Al-Pb alloy coatings by high current pulsed electron beam cladding

To improve the surface hardness and wear resistance of Al-Pb alloys, pure aluminum (Al) surfaces coated with lead (Pb) layers were irradiated by using high current pulsed electron beam (HCPEB) to prepare Al-Pb alloyed layers with excellent properties. The surface roughness of the alloying layer was observed by 3D laser scanning microscope (LSM). Meanwhile, the micro morphology, structure and element distribution of Al-Pb coating before and after irradiation alloying were analyzed by field emission scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). In addition, the phase composition of the alloy layer was observed by X-ray diffraction (XRD). Moreover, the surface microstructure after alloying was characterized by transmission electron microscopy (TEM). Finally, the microhardness, average friction coefficient and wear rate of the sample surface before and after irradiation were tested, and the hardness and wear enhancement mechanism were analyzed. The strengthening mechanism of the surface performance was also summarized. The internal relationship between surface microstructure and surface properties of irradiated coatings was established. The results show that after HCPEB irradiation treatment, the Al substrate and Pb coating show good metallurgical bonding, and after 30 times of irradiation, the Pb-Al alloying layer with a thickness of about 10.2 mu m is prepared. Compared with pure aluminum and the original coating, the diffraction peak of (111)(Al) crystal plane is widened after 30 times of irradiation, and the position of the diffraction peak is also slightly shifted to the low angle direction, which means that the Al grains on the surface of the matrix are significantly refined after the surface alloying treatment of HCPEB, and the crystal cells expand, and the lattice constant increases. HCPEB induces the formation of sub crystals, dislocations, dislocation cells, a small amount of Al(Pb) solid solution and a large number of nanoscale Pb rich particles on the sample surface. The test results show that the hardness and wear resistance of Al-Pb coating surface are significantly improved after electron beam irradiation.