In this study, the wear behavior of a heat-treatable Al-7Si-0.5Mg-0.5Cu alloy fabricated by selective laser melting was investigated systematically. Compared with the commercial homogenized AA2024 alloy, the fine secondary phase of the SLM Al-Cu-Mg-Si alloy leads to a low specific wear rate (1.8 ± 0.11 × 10−4 mm3(Nm)−1) and a low average coefficient of friction (0.40 ± 0.01). After the T6 heat treatment, the SLM Al-Cu-Mg-Si alloy exhibits a lower specific wear rate (1.48 ± 0.02 × 10−4 mm3(Nm)−1), but a similar average coefficient of friction (0.34 ± 0.01) as the heat-treated AA2024 alloy. Altogether, the SLM Al-3.5Cu-1.5Mg-1Si alloy is suitable for the achievement of not only superior mechanical performance, but also improved tribological properties.

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In order to improve the adhesion and water resistance of waterborne polyurethane (WPU) adhesive, a kind of amino-terminated hyperbranched organosilicon (HPSi-NH2) was first synthesized by using trimethylchlorosilane, diethoxydimethylsilane, and γ-aminopropyltriethoxysilane (KH550) as raw materials. Then, HPSi-NH2, as the cross-linking agent, was used to modify the polyurethane prepolymer to obtain HPSi-NH2-modified WPU (HSiPU). The single-factor experiment results showed that when the amount of HPSi-NH2 was 2.0 wt %, the adhesion properties of HSiPU-2 were the best. Compared with the HSiPU-0 film, the water absorption rate of the HSiPU-2 film decreased by 10.9%, the water contact angle increased by 26.3°, the tensile strength increased by 10.1 MPa, and the elongation at break increased from 630.7 to 813.0%. HSiPU adhesive was used in the bonding of the goat leather substrate, and the results showed that the peel strength of leather bonded by HSiPU-2 was increased from 1.38 to 3.15 N/mm, and the maximum peel force was increased from 1.67 to 5.51 N/mm, which indicated that the bond strength of HSiPU adhesive with different contents of HPSi-NH2 can be used for bonding substrates with different cohesion strengths.

The relationship between processing parameters, microstructure, and mechanical properties of Al-8.3Fe-1.3V-1.8Si alloy processed by laser powder bed fusion is seldom studied. Therefore, fully dense alloys with two parameters were selected to investigate this key issue. The results show that the alloy with low power and scanning speed (S200) shows fan-shell-shaped melt pools and laser tracks while another (S350) shows a deeper and wider melt pool. Both alloys obtain a heterogeneous microstructure without a secondary phase in melt pool (MP) and a nano-sized phase in melt pool boundary (MPB). The difference between solid-solution strengthening and Orowan strengthening in MP and MPB contributes to the difference in compressive yield strength (S200: 380 ± 14 MPa and S350: 705 ± 16 MPa), and heterogeneous nano-hardness results in different crack behaviours and failure strains. This work indicates that adjusting processing parameters is an effective method to control microstructure and mechanical properties of this alloy.