| With the growing market demand for aluminum,it is increasingly important to improve the performance of aluminum and thus broaden the range of applications.By using refiner and modified treatment,physical refinement,and controlled processes to optimize the solidification organization and thus obtain aluminum alloys with high mechanical properties.In this paper,ZL101 and Al-5Cu alloy were used as the output equipment,and ZL101 and Al-5Cu alloy were used as the research objects of this experiment.In the experiment,the two alloy melts were treated with electric pulse,refiner、modified and combined treatment respectively,and the effects of refiner and modified on the solidification organization and properties of the alloy,the effects of electric pulse parameters on the solidification organization and properties of the alloy,and the effects of combined treatment on the solidification organization and properties of the alloy were studied,The results of the test revealed the following.The optimum pulse frequency and pulse voltage parameters for the solidification of ZL101 and Al-5Cu aluminum alloys under electric pulse treatment conditions were20 Hz,20 V;50 Hz,3.5 V.The eutectic silicon growth distribution in the solidification structure of ZL101 was improved,and the size of primaryαgrains in the solidification structure of Al-5Cu was reduced,and the tensile strengths of the samples were increased by 9.4%and 7.7%,respectively;with the addition of 0.01%～0.02%Sr to the melt of ZL101 aluminum alloy under the condition of modified treatment,the eutectic silicon phase could obtain good metamorphic effect;with the addition of 1.0%Al-5Ti-1B to the melt of Al-5Cu aluminum alloy,the tensile strengths were increased by 24.6%and 10.0%,respectively.1.0%Al-5Ti-1B in Al-5Cu aluminum alloy melt,the solidification organization was fully refined and the tensile strength was increased by24.6%and 10.0%,as well.The tensile strength of ZL101 alloy samples was improved while that of Al-5Cu alloy samples was slightly reduced when the two alloy melts were treated together with the best process parameters under single conditions.The difference between the two combined treatment results is that the observation of the microstructure reveals that the combined treatment of ZL101 alloy can significantly optimize the phenomenon of weakened Sr metamorphism due to the enrichment of silicon atoms in the adjacent primary crystal and primary crystal secondary dendrite interstices,and has a significant improvement effect on the eutectic silicon in the grain boundary segregation region,optimizing the Sr metamorphism effect and improving the tensile strength of the samples.The tensile strength of the samples was slightly lower than that of the single refiner treatment when the Al-5Cu alloy melt was treated with the combined treatment.The research analysis concluded that D at the solid-liquid interface increased during the combined treatment,k_edecreased,and the solute concentration at the grain boundary increased after the initial crystal growth,which played a purifying effect on the alloy solute,thus reducing the tensile strength of the samples.Considering from the solute solid solubility,which Al elements,Cu elements both high temperature can form an infinite solid solution of replacement solid solution,when cooled to room temperature still has a high solid solubility,there is a chance to form supersaturated solid solution.When the electric pulse compound treatment due to the effect of Joule heat to increase the temperature of the melt around the electrode,reduce the cooling solidification rate of the alloy,Cu atoms solid solution precipitation time is greater than without electric pulse treatment,the solid solution degree in the primary crystalαsolid solution is reduced,solid solution strengthening weakened resulting in a lower tensile strength of the samples. |
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