## 1 Introduction  
In recent years, Al-Si alloys have been widely used in the manufacture of vehicles, due to their excellent physical properties, including low desity, high strength-to-weight ratio, good fluidity, low coefficient of thermal expansion and good machinability [1]. However, under the conditions of the traditional casting process, Al-Si alloys usually contain massive coarse, long-needle or lamellar shape eutectic Si phases. Those defects often lead to poor mechanical properties and wear resistance. The addition of rare earth (RE) [2], Sr [3], Al\({}_{2}\)O\({}_{3}\)[4], or SiC [5,6], and heat treatment [7], are effective ways to change the morphology and distribution of the eutectic silicon phase in the Al matrix to improve the mechanical properties of the alloy. [PERSON] [5] studied the effect of situ synthesizing SiC particles on the Al-Si alloy. An in situ 2% SiCp reinforced Al-Si alloy was designed. The hardness and wear resistance were improved. Besides, it was regarded that the in situ SiC particulates act on the process of heat treatment, which affected the mechanical properties as a result. But, the samples were prepared by traditional method and the wear mechanisms were not analysed. [PERSON] et al. [6] studied the wear behavior of the Al-Si-SiCp composites by using a reciprocating friction wear test. This study showed that nomal load, reciprocating velocity, sliding distance, and silicon content all had a significant effect on the wear property of the samples. Among these factors, it was found that the increased Si content altered the composites' wear resistance. On the other hand, [PERSON] et al. [8] studied the microstructures of the Al-Si alloy and found that they were altered by T6 heat treatment. T6 heat treatments increased the hardness, strength, elongation, and wear resistance of the alloy. [PERSON] et al. [9] reported the influence of wear test parameters on the wear performance of Al-composites of mechanical parameteres, such as: applied load, sliding velocity, sliding distance, temperature, and counterface hardness. The results revealed that these parameters can influence the wear and tribology behaviors of Al-composites in dry sliding wear tests. Recently, the process of non-contacting method using an electromagnetic field is being conducted. When compared to traditional stirring casting, this method has the advantages of nonpollution, easy process control, and continuous production [10]. It has been a main method for producing the semi-solid slurry or billets. Therefore, electromagnetic stirring (EMS) is one of the most promising methods for processing cast products. EMS with optimal parameters has a remarkable ability to improve the macrosopic quality of billet [11]. Stirring power is a key process factor and has a direct and positive influence on microstructural evolution [12; 13; 14]. The suitable slight electromagnetic stirring that is applied to the melt during the low superheat pouring can increase the number of crystal nuclei in the melt to reduce the grain size, and can make the primary phase morphology to become more round. [PERSON] [15] believed that this process resulted in the distribution of SiC particles evenly with a low porosity. [PERSON] found that SiCp were evenly distributed in the matrix due to the melt flow that is induced by the rotating magnetic field of electromagnetic stirring. This indicates the effectiveness of the technique electromagnetic stir casting process that is utilized for the production. In a word, the EMS method can improve the mechanical properties and microstructural composition of the alloy, and may improve the wear resistance of the alloy. Few literatures can be found to reveal the effect of T6 heat treatment on the wear properties of Al-Si alloys that are reinforced with SiCp processed by electromagnetic stirring method. T6 heat treatment refers to a solution treatment at 520-550 \({}^{\circ}\)C for several hours, followed by quenching and artificial ageing [16].