Research On Damping And Creep Properties Of SiCp/AZ61 Magnesium Matrix Composites

Nowadays,the issue of Magnesium matrix composites has been came into the concern from the researcher's attention all over the world ,as its low density, high intensity and rigidity, and as well as its excellent propertities such as high temperature resistance and high shocking resistance capability, and good absorbing quality. In this paper, SiCp/AZ61 composite was made by using the magnesium alloy as Matrix,SiC particulate as the enhanced phase,in addition,through three different stir casting technique(such as stirring in a fully liquid condition, stirring in a semi-solid condition, stirr-melting process ).Moreover, using metallographic phase microscope to observe three different metallographic phase units from three different preparation technique in Stir casting, and the microstructural structure of SiCp/AZ61 composite affected by stir-casting process was analyzed. Forthemore,research on the formation about the theory of SiC particulates and AZ61 matrix of SiCp/AZ61 composite,Stirring-melt casting process was ascertained as a fitting preparing process of SiCp/AZ61 composite. The Mechanical Properties of SiCp/AZ61 magnesium Matrix composite was tested through eletron tensile testing machine with different processing parameters. And in this foudation, optimization result was made by Orthogonal experimental design to get the best fabricating process scheme.The damping property and creep property of matrix alloy AZ61 and SiCp/AZ61 composite prepared by means of stirring-melt casting process were measured by dynamic mechanical thermal analyses (DMA-Q800). The dependence of the damping capacity of SiCp/AZ61 composite on strain amplitude, frequency and temperature has been analyzed by studying the internal friction spectrum of matrix and composite. On the basis of the interface damping and the dislocation damping, the reason of increasing of damping property on SiCp/AZ61 composite was construed. The results of damping-strain amplitude curve show that dislocation brought by SiC particles play an important role in the increasing of damping property of composites, which can be explained by G-L dislocation pinning theory.The results of damping-temperature-frequency curves show that the improving of damping property of composite in high temperature is due to so much minimal slip of interface in composite. The creep curves of matrix alloy and SiCp/AZ61 composites prepared by stirring-melt casting process at isothermal and were studied.It is found that compared to matrix alloy AZ61, the SiCp/AZ61 composite has shorter initial creep time, lower state-creep velocity and little total transformation. The creeping resistance of Matrix alloy AZ61 was enhaced when mixed with enhanced phase-SiC particles. It is because that the SiC particles substitutes Mg₁₇Al₁₂ phase on grain boundary which will be easliy intenerated at high temperature. The pinning effect of SiC particles prevent dislocation and slipage of grain boundary at high temperature.