Study On Al Matrix Composite Preparation And Forming With Solid-state Compound Process

According to the status when the particles were added into matrix alloy, the composite process was divided liquid process and semi-solid process. But in composite material fabrication process, there have been a bad wettability of reinforcing particles, harmful interface reaction and particle partial gather, etc. These problems have greatly affected composite materials comprehensive property improvement and application. Therefore, as solid and semi-solid concepts extending, in this paper, the solid-composite process has been put forward. The SiCp/Al solid state compound process and die cast process had been investidigated.Reinfoced partile pretreatment was premise step of particle reinfoced preparation. SEM and EPMA analysis show that ,on the mainly SiC particles surface,there were a lot of submicron SiC particles and a little Fe, Mn, V, Ni. The pickling and soaking could delete the impurities effectively. Additionally, in order to avoid harmful interface reaction between the SiC particles and liquid aluminum, when the compound billet was molten, the high temperature oxidation treatment had been done to the pickling particle. The oxidation weight increment experiment showed that the oxidaton layer formed on the SiC particle surface after 1000℃6 hours oxidation treatment. According to calculation, the oxidation layer was117 nm.After pickling and high temperature oxidation, solid-composie adopted, the SiC particles were mixed with aluminum powder to study reinfoced particle distribution in the matrox alloy. Then, by the means of cold and hot process the mixed powder were made up to compound billet. In this mixture process, in oder to avoid aluminum powder oxidize the container was full of Ar. The result showed that the particles were distributed well when tha mixture time was 1.5 hours.The vacuum hot process was adopted to increase the plasticity of aluminum powder. The hot process was conducive to reduce blocking pressure when compound billet was produced. And the hot process also promoted SiC particles combine closely with aluminum powder.The compound billets were put into poor-aluminum 7090Al alloy and scattered stirred by electromagnetic to the semi-solid. Then the semi-solid slurry was diecasted and the casting part was analyzed. The analysis showed that SiC particles distributed well in the matrix alloy, the particle combined closely with matrix alloy, however, the harmful interface reaction and particle reunion din't take place. And the friction and wear experiment showed that the composite material friction factor was little, further, there was no scratch on the friction pair. Those indicated that the SiCp/Al composite had a good friction property.