Laser Cladding Process and Performance of Copper-based Alloy for Aluminum-based Engine Valve Retainer

This paper aims to improve the wear resistance and erosion resistance of the engine valve rerainer and prolong the life of the engine. The paper adopted laser cladding to prepare copper-based alloy cladding for aluminum-based engine valve retainer, and studied the relationship between laser cladding process and cladding performance. Taking dilution rate and cladding contact angle as measurement criteria to optimize parameters, the paper studied the relationship between laser scanning speed, powder feeding rate, laser remelting parameters and microstructure and morphology of cladding layer. Through a series of experiments, the surface structure of the cladding layer was refined with the increase of the scanning speed. At the same time, the dilution rate of the cladding layer and the contact angle of the cladding layer increased, while the dilution rate and the cladding layer contact angle increased with the powder feeding rate. The increase is on a downward trend. By changing the parameters of laser remelting, the distribution of the strengthening phase in the cladding layer can be changed, thereby changing the hardness of the cladding layer. By analyzing the shear section, the results show that the shear strength of the bonding interface first increases and then decreases with the increase of the scanning speed. When the scanning speed is 8 mm/s, the shear strength is the highest, up to 142.31 MPa. Under the optimal parameters, the average hardness of the cladding layer is 392HV0.05, which is equivalent to 4.6 times the hardness of the ZL104 aluminum alloy matrix (about 85HV0.05). In conclusion, the erosion wear and pin-disk wear experiments of the cladding layer show that the copper-based coating has the lowest friction factor and the lowest erosion mass loss, which confirms that the copper-based coating can improve the wear resistance and erosion resistance of engine valve raw materials. Furthermore, the life of the engine cylinder block is improved to a certain extent, all of which provide certain guidance for practical application. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.