The surface of the aluminum alloy is prone to oxidation, which in turn affects the quality of the weld. The 5A12 aluminum alloy was cleaned by acousto-optic Q-switched diode-pumped Nd:YAG laser and the effects of different laser powers and different cleaning speeds on the surface roughness, microstructure, element content, microhardness, residual stress and corrosion resistance of aluminum alloy were investigated. The results show that when the power is 98W and the cleaning speed is 4.1 mm/s, the effect of Nd: YAG laser on the removal of oxide film on 5A12 aluminum alloy surface is the most effective. After laser cleaning, the smoothness and strength of aluminum alloy surface can be effectively improved. However, as a major element in 5A12 aluminum alloy, the content of magnesium decreased. At the same time, the residual tensile stress was generated on the surface of the aluminum alloy after cleaning, and the corrosion resistance slightly decreased.

In this paper, a variety of micro-textures made by imitating the biological body surface are mentioned, and four common biomimetic texture types—convex hull, pit, groove and corrugation—are summarized by referring to a large number of literatures. These texture types that are widely used are those of the grooves and the pits of non-smooth surface because their viscosity drag reduction effects are relatively optimal for wear-resistance; in view of these two types of textures (with others including pit diameter, groove width, depth and area of share, and morphology spacing), we use data analysis and comparisons to find optimal parameter values in order to find the optimal effect of drag reduction and anti-sticking wear-resistance. Several texture processing methods are briefly introduced through case analysis and an illustration of the viscosity drag reduction mechanism of wear-resistance, and general fluid dynamic pressure is deduced from a theory formula in order to facilitate future research work on the basis of the optimal parameters to further improve the friction, wear lubrication, and hydrophobic properties, thus improving the bionic texture surface efficiency of saving energy and reducing consumption in industrial applications.

This article reviews the current status of automotive brake disc research and the prospects for future research. At present, the research of brake disc performance mainly includes thermal conductivity, thermal fatigue resistance, wear resistance, and brake noise. It is found that a new alloy composite, heat treatment process, ceramic composite, new structure, and new materials are emerging. At the same time, it was found that ceramic and resin were used as the matrix, fiber materials were used as reinforcements to prepare brake discs, the addition of new fillers and the study of special reinforcement materials have become new hotspots in the study of brake discs. In the future development, carbon-fiber ceramic brake discs may become the main research focus of brake discs.

FeCoNiTiAl_x (x = 0, 0.5, 1) high-entropy alloy coatings were prepared by laser cladding technology. The phase, microstructure, hardness, wear resistance and corrosion resistance were tested and analyzed. The results showed Al element promoted the conversion from the FCC phase to the BCC phase. The coating presented dendritic structure due to the addition of the Al element, while the number of dendrites increased. And the average hardness of the coating increased from 204 to 623 HV. The addition of the Al element increases the corrosion current density of the coating from 1.270 × 10⁻⁵ to 3.489 × 10⁻⁵ A/cm². The wear rate of the coatings decreases with the increase of Al content according to dry friction and wear, which indicates the wear resistance of the coating was improved by adding the Al element. According to the corrosion wear test in 3.5% NaCl solution, it can be found that the wear rate of the coating increases firstly and then decreases with the addition of the Al element, which indicates that the addition of the Al element intensifies the wear of the coating in 3.5% NaCl solution.

The CoCrFeNi high-entropy alloy coatings (HEACs) with different weight ratios (10 and 30 wt.%) of WC additions have been prepared using mechanical alloying and a vacuum hot pressing sintering technique on a Q235 steel substrate. The microstructures, microhardness, wear resistance, and corrosion resistance of HEACs were studied. The CoCrFeNi(WC) powders were obtained by mixing the CoCrFeNi HEA powders and WC particles. The sintered products of both HEACs with high relative density contained one solid solution phase with face-centered cubic structure, WC, and unknown precipitate phases. The transition boundary had a good metallurgical bonding with the coating and substrate. The average microhardness values of CoCrFeNi HEACs with 10 and 30 wt.% WC additions reached 475 and 531 HV respectively, which were far higher than that of the substrate (160 HV). Moreover, both coatings exhibited better wear resistance than the substrate under the same wear conditions. The 30 wt.% WC HEAC displayed the lower friction coefficient, and the shallower wear groove depth. The grain refinement strengthening and second-phase particle strengthening could be beneficial to the enhanced hardness and wear resistance of coatings with WC additions. The corrosion behavior of the tested samples in the 3.5 wt.% NaCl solution were investigated using electrochemical polarization measurements. The CoCrFeNi(WC) coatings all revealed the improved corrosion resistance. Especially, a 10 wt.% WC addition remarkably enhanced the comprehensive corrosion resistance and easy passivation of CoCrFeNi HEAC.