IntroductionAluminum matrix composites reinforced by SiC particles are widely used in aviation, aerospace, automotive, electronics, and other fields due to their high specific strength and specific stiffness, excellent wear resistance, and low density. Research efforts regarding such composites have been primarily focused on the characteristics of SiC particles, aluminum matrix selection, and the effect of the preparation process on the structure and performance of the composites [1][2][3][4][5][6][7].Al-Mg alloys are one type of the aluminum alloys that can be heat strengthened, and are widely used as automotive body panel material. The microstructure and properties of the alloys can be further controlled by micro-alloying with Si and Cu elements. In general, SiC particle reinforced Al-Mg-based composites are prepared by casting methods, including infiltration casting, transfer molding and gravity casting method, etc. In this method, the matrix alloy is first melted, and the SiC particles are subsequently added to the melt, or the melt is added to a previously prepared SiC body. One disadvantage of this method is the heterogeneous distribution of the SiC particles in the matrix [5][6][7][8][9][10][11][12]. The powder metallurgy (PM) method, as one of the advanced preparation methods, is also commonly used to prepare SiC particle reinforced AlMg-based composite materials [13][14][15][16][17]. Asgharzadeh studied the effect of the SiC content on the SiC distribution and microstructure during the sintering process of a SiC/Al-1.0Mg-0.6Si-0.2Cu-0.1Fe (mass%) composite [15]. Their results indicated that SiC particles reduced the sintering density of the composite. Yan et al. [16] studied the influence of SiC particle contents (25~35 vol.%) on a SiC/Al-1.0Mg-0.6Si-0.2Cu (mass%) composite. It showed that the densification, thermal expansion coefficient of the composite and the tensile strength of the composite decreased with the increasing SiC particle content.The microstructure and properties of SiC particle reinforced PM Al-Mg-based composites are affected by the particle size and volume fraction of the SiC particles, the matrix alloy composition and the sintering process employed [7,9,10,12,15]. Subsequent thermomechanical treatment processes also have an effect on the mechanical properties of composite material, such as the solution treatment process [11]. However, the effects of solution treatment temperature and SiC particle on SiC/Al-Mg-Cu-Sn composites are not reported in the literature. This work is purposed to study the effects of solution treatment temperature and SiC particle contents on the microstructure, mechanical properties and corrosion behavior of PM SiC/Al-Mg-CuSn composites. Experimental MethodsSpherical Al-0.64 Mg-0.60 Cu-0.36 Sn-0.22 Fe-0.18 Zn-0.04 Si (mass%) powder (Taigang Group Aluminium Powder Co., China) and SiC particles (99.6%) (Xuzhou Jiechuang New Material Technology Co., China) were used as the raw materials. The average diameters of the matrix alloy powders and SiC particles are 20 μ...