3 / 2024-05-14 16:42:19

Ultrasonic/laser alloying in-situ synthesized particle reinforced AMCs coatings microstructure and properties study

Ultrasonic vibration,Laser alloying,In-situ synthesis,Aluminium matrix composite coatings,Frictional wear properties

Utilizing eco-friendly and effective laser surface modification technology to prepare particle reinforced aluminium matrix composites (AMCs) coatings can significantly improve the wear resistance of aluminium alloy surfaces , thereby prolonging their lifespan. However, due to the rapid melting characteristics of laser processing and the difference in physicochemical properties between the particle reinforcements and the aluminium. Leads to elemental segregation, non-uniform spatial distribution of the particle reinforcements, cracks and porosities are likely to occur during the laser preparation of AMCs coatings, which will reduce the performance of AMCs coatings.

In this paper, in-situ synthesized TiC-TiB₂ particle reinforced AMCs coatings was prepared on the surface of 7075 aluminum alloy using ultrasonic vibration assisted laser alloying process. The overall morphology, physical phase composition, microstructure, microzone composition, microhardness and wear-resistant properties of the coatings under different ultrasonic amplitudes were analyzed. The non-linear effects such as cavitation effect, acoustic flow effect and mechanical stirring induced by ultrasonic vibration were investigated on the influence mechanism of intermetallic compounds and in-situ reinforcements size, morphology, quantity and spatial distribution in the coating. The strong convection in the melt pool produced by the ultrasonic vibrations resulted in an improvement of the coating surface macro-morphology, a slight increase in roughness, and an increase in coating thickness and dilution. With the increase of ultrasound amplitude, the acoustic cavitation effect and the acoustic flow effect are enhanced, and the microstructure of the coating is significantly refined. The in-situ synthesized reinforcement particles were not only increased in number but also more uniformly spatially distributed. The microhardness of the coatings was significantly increased and more uniformly distributed after assisted ultrasonic vibration. The wear resistance was approximately 11.8 times that of the substrate, and 4.1 times that of the coating without ultrasonic vibration.