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The microstructure evolution, corrosion resistance, and wear resistance of Al–18Si–4 Mg–2Mn–0.5Fe–xCu (x = 0,1,2,3,4,5 wt%) alloys prepared by laser additive manufacturing (LAM) process are studied. It is found that the addition of Cu not only produces Cu‐rich strengthened phase, but also promotes the precipitation of the second phase. With the addition of Cu, the corrosion resistance of the alloy decreases, which is due to the increase of potential difference caused by the increase of the strengthening phase. The addition of Cu can effectively inhibit corrosion cracking. The hardness and wear resistance of the alloy increase with the increase of Cu content under the synergistic strengthening of the Q‐Al5Cu2Mg8Si6 phase and Al2Cu phase. When the Cu content is 3 wt%, the hardness and wear resistance of the alloy are the best. However, with the increase of Cu content, part of the Q phase is transformed into the Al2Cu phase; this synergistic strengthening effect is weakened, and the hardness and wear resistance of the alloy are reduced, but still higher than that of the alloy without Cu addition, which indicates that the addition of Cu can effectively improve the hardness and wear resistance of the alloy. [ABSTRACT FROM AUTHOR]

Many engineering structural parts, such as internal gear pumps, worked in high-salt and high-temperature environments. The material (40Cr) of the parts in the pump failed due to severe wear and corrosion. To improve the wear resistance and corrosion resistance of 40Cr, the FeCoNiCrMox (x = 0, 0.3, 0.6, 0.9, 1.2) HEAs coatings were deposited on the surface of 40Cr by laser cladding technology, and the phase structure, microstructure and hardness of the coatings were investigated. In addition, friction and wear tests, electrochemical tests and neutral salt spray tests were conducted to investigate the effect of Mo content on the wear resistance and corrosion resistance of the coatings. The results showed that the phase structure of the FeCoNiCrMo0 coating was the FCC phase, and the phase of the FeCoNiCrMox (x = 0.3, 0.6, 0.9, 1.2) coatings were composed of the FCC phase and σ phase. The Mo element was enriched in interdendrite. With the increasing content of Mo elements, solid solution strengthening, fine grain strengthening, and second phase strengthening occurred in the coatings, which led to the increased hardness and wear resistance of the coatings. The FeCoNiCrMo1.2 coating had the best wear resistance. In the 3.5%NaCl solution, the corrosion resistance of the coatings was better than that of the substrate. With the increase of Mo content, the corrosion potential of the coatings drifted positively, the corrosion current density decreased, and the corrosion resistance increased. However, with excessive Mo element content, the σ phase will precipitate, leading to galvanic coupling corrosion of the coatings and reducing the corrosion resistance. Because the FeCoNiCrMo0.9 coating had the highest corrosion potential and the lowest corrosion current density. Therefore, it had the best corrosion resistance. The neutral salt spray test result also showed that the corrosion resistance of the FeCoNiCrMo0.9 coating was the best. [ABSTRACT FROM AUTHOR]