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In this paper, Al -10 % Si , Al -20 % Si and Al-30% Si three high silicon aluminum -based alloy as the research object , based die casting technology , high silicon aluminum -based alloy gravity casting and die casting specimens organization and performance , to carry out a study of high silicon aluminum base alloy die-casting process , injection speed , pouring temperature on the microstructure and mechanical properties of die-cast specimens . On this basis , the Si content on the microstructure and mechanical properties of high- silicon aluminum -based alloy . Experimental results show that : compared with the gravity casting , die casting can significantly refine the newborn high silicon aluminum -based alloys organizations α - Al eutectic and primary Si phase , inhibit the growth of primary Si phase , to improve the mechanical properties of the alloy . With the increase of the injection speed , the Al - 10 % Si and Al - 20% Si alloy specimens , tensile strength , elongation and impact toughness first increases and then decreases , the hardness decreases ; Al -30 % Si alloy specimens , tensile strength , elongation, impact toughness and hardness first increases and then decreases . With the pouring temperature is elevated , the tensile strength of the Al - 10% Si and an Al- 20% Si alloy specimen , elongation , impact toughness and hardness first increases and then decreases ; mechanical properties of Al -30 % Si alloy increased with increasing casting temperature . Casting process parameters as the pouring temperature of 720 ° C , injection speed of 2.5 m / s , mold temperature of 150 ° C , working pressure 160Bar the tensile strength of the Al -10 % Si alloy die casting 233MPa, elongation 8.57% , hardness 57.9 ; Al -20 % Si alloy die-casting pieces of the tensile strength of 280MPa, elongation , 4.83% , the impact toughness 25.56J/cm , hardness 80.6 . Injection speed of 2.5 m / s , the pouring temperature of 740 ℃ , Al-30% Si alloy obtained by the microstructure and mechanical properties , tensile strength 240MPa, elongation of 2.97% , impact toughness 15.95J/cm ~ 2, the hardness of 88.9. With the increase in the Si content , the phase gradually increased the number of die-cast high silicon aluminum -based alloy Si Si phase continue to grow . In the optimization of the process parameters , as the Si content increases , the tensile strength of the high silicon aluminum base alloys first increases and then decreases gradually increased hardness is gradually decreased while the elongation and impact toughness . In the study of high silicon aluminum base alloys , from the mechanical properties , Si content in the 20%, the better the comprehensive performance of the alloy .
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