Preparation And Wear Resistance Of Al-Si-Mg Si Autogenous Composites

Situ composites reaction occurs in the matrix strengthening phase, thereby enhancing the performance of the material. The electromagnetic stirring is commonly used in smelting metal material with a non-contact, controllability, non-polluting and favored by material industry. In this paper, the electromagnetic stirring were applied to prepare Al-Si alloy. The materials were divided into two kinds of single-component alloys:over the eutectic Al-17%Si-11%Mg and hypoeutectic alloy A356mechanical properties of the alloy by adjusting the electromagnetic stirring parameters to achieve grain refinement. Another use of the electromagnetic stirring, is to add the rare earth element La to improve the performance of eutectic Al-17%Si-11%Mg alloy by composite technology, and compared the hardness and wear resistance with those of the simply applied electromagnetic stirring. The experimental results are obtained as follows:(1) With the frequency of electromagnetic stirring increasing sequentially from OHZ up to20HZ,30HZ, and40HZ, respectively, the composite the Mg2Si particles of size decreases while the roundness becomes larger and larger. As the Mg2Si particles was refined, the hardness and wear resistance of the composite materials were improved.(2) As the electromagnetic stirring time increases sequentially from Os to5s,10s,15s, the Mg2Si particle size of the composite first decreases and then becomes large with its roundness almost remaining in constant. Due to the mechanical properties of the alloy depending on its organizational structure, its hardness and wear resistance is first increases and then decreases.(3) With the frequency of electromagnetic stirring increasing from OHZ up to20HZ,30HZ and40HZ, the primary α-Al grain size in A356alloy has slightly rebounded after decreasing and meanwhile its roundness first increases and then decreases.(4) From the point of view about the energy saving, as the frequency of the electromagnetic stirring is40HZ, the corresponding electrical power consumption is almost twice times of that when its frequency is30HZ, with its shape factor decreased by9.0%and its grain size increasing by19.0%.(5) With the electromagnetic stirring time increasing from0s up to5s,10s,15s, respectively, the primary α-Al phase grain size in A356alloy first decreases and then increases, and its roundness experiences the same change as first decreasing and then increasing.(6) Compared with its simply external electromagnetic stirring preparation, the primary Mg2Si phase shape factor in Al-17%Si-11%Mg-0.5%La alloy micro structure which is based on the complex process preparation has increased by19.4%, and its grain size has decreased by78.6%with its hardness increasing by23.1%and the amount of wear decreasing26.1%. The results obtained from this study are verified to have improved the organizational structure of the Al-Si alloy, including its hardness and wear resistance. This research could have some certain guidance on the practical application of Al-Si-Mg2Si composite.