Abstract
SiC particles (SiCp)-reinforced Al–Si matrix composite coatings were synthesized on 4032 aluminum alloy by laser cladding using powder mixtures of Al-20 wt.% Si alloy and electroless copper-plated SiC particles (SiCp-Cu). The effects of SiCp-Cu content on microstructure, phase composition, and microhardness of the SiCp/Al–Si laser cladding layer (LCL) were investigated systematically. The results showed that the microstructure of SiCp-Cu/Al–Si LCL was mainly composed of undissolved SiCp, lump-like primary Si, lump-like Al2Cu, plate-like Al4SiC4, and Al–Si–Cu ternary eutectic. In addition, the eutectic microstructure became finer with the increasing of SiCp-Cu content. The average microhardness of the LCL increased with the increasing of SiCp-Cu content. When SiCp-Cu content was 50 wt.%, the average microhardness of the LCL reached 508 HV0.05, which was about 3.5 times larger than that of the substrate. The LCL reinforced with a SiCp-Cu content of 30 wt.% exhibits the best wear resistance.
Highlights
Aluminum alloys are extensively applied in the automotive industry and aircraft and other fields due to their reduced density, light weight, and high specific values of stiffness and strength.the use of aluminum alloys for a wider range of application is limited due to their low surface hardness and poor wear resistance [1,2,3,4]
Sun et al [17] fabricated composite coatings of Al–Si alloy reinforced with SiC particles on AlSi12 substrate; the microstructure and microhardness of the coatings were investigated, and the results showed that the coatings had much higher microhardness than that of the substrate, and the coatings were divided into two sublayers; the upper layer was composed of Al–Si eutectic, acicular primary Si, α-Al dendrites, and a little SiCp, while the bottom layer consisted of α-Al dendrites, Al–Si eutectic, and a large amount of SiCp
1) SiCp-reinforced aluminum matrix composite coatings with high microhardness can be successfully obtained on the surface of 4032 aluminum alloy by the laser cladding process
Summary
The use of aluminum alloys for a wider range of application is limited due to their low surface hardness and poor wear resistance [1,2,3,4]. It is necessary to improve surface properties and mechanical properties and prolong the service life of the parts made from aluminum alloys [5,6,7]. In order to improve surface properties of aluminum alloys, various attempts have been made, such as electroplating [8], electroless plating [9], thermal spraying [10], anodizing [11], and microarc oxidation [12]. Compared with conventional surface treatment methods, the laser cladding process has the advantages of low clad dilution, rapid heating and cooling, small heat-affected zone, and good adaptability of surface properties [13,14,15,16]
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