| Small proportion of high silicon aluminum alloy with good wear resistance, heat resistance and low thermal expansion coefficient, easy-to-casting molding, and many other advantages, is a place of preparation of iron-based materials, automotive piston, connecting rod, air-conditioning compressor rotor and blades, and other important. Part of the ideal material. Widely used in aerospace, automotive, shipbuilding, machinery and other industrial production sectors. But the high silicon aluminum alloy solidification mostly in coarse primary Si phase growth of polygonal shape, a serious split of the collective, the deterioration of material properties, limiting its wide application in industry. Therefore, we must change the morphology of silicon alloys, reducing the performance of its weakening effect on the body. This paper discusses the high and low cross against the post-Al-Si alloy microstructure and mechanical properties and high-silica ZA27 silicon microstructure and properties against each other, but also discusses the Bi, Sb alloying elements on the high silicon alloy ZA40 and properties of .Experiments using JB-300B impact testing machine, TH160 Leeb Hardness Tester, SHD-A infrared electric oven, 4XC binocular microscope and properties of the alloy were investigated.The main conclusions are as follows:(1) Mixed melting process of each Al-16% Si alloy refining and properties of primary Si has improved greatly superior to conventional smelting technology Al-16% Si. Pouring temperature of 750℃, the hardness from 74 to 79, the impact toughness value from 8.08 J/cm~2, increased to 9.20 J/cm~2. Chilling temperature and composition non-uniformity is to make the Al-16% Si alloy in the refinement of primary Si phase the main reason.(2) Mixed melting process each containing 5% Si of the mechanical properties of ZA27 alloy has improved greatly superior to conventional smelting process and containing 5% Si of the ZA27 alloy. Pouring temperature at 720℃, the hardness increased from 106 to 139, the impact toughness increased by the 3.03 J/cm~2 to 6.57 J/cm~2. (3) ZA40 alloy containing Si, adding Bi element in the rapid solidification process of metal type, except a small and foreign, a large number of pure Bi Biαamount of Bi-phase solution to the phase dispersed in the matrix. Bi alloy elements on the refinement of primary Si has to include the 0.9% Bi when the effect is most obvious. Bi alloy elements added were lower than the hardness of the alloy without Bi as Bi content increases, the alloy hardness continues to increase. With the increase of Bi content in the alloy toughness first increases, then decreases, while adding 0.9% Bi alloy toughness the largest 3.83J/cm~2.(4) The ZA40 alloy in the silicon by adding Sb element, theαdendrites passivation to improve the alloy hardness, Sb and Zn alloy to form compounds Sb3Zn4, destruction of the grain boundary exists in the continuity of the matrix, the alloy toughness decreased. Sb to join, making the alloy in the refinement of primary Si, which added 1.6% Sb best. |
PDF Full Text Request