Study On Organization And Mechanical Properties For High Strength And Toughness Of Cast Alloys

Casting aluminum-silicon alloy is the most widely used aluminum alloy due to its good casting property. As the general mechanical properties of cast aluminum-silicon alloy is not high enough to meet certain performance requirements of high demand for components,thus limiting th alloy in the casting on the application.How to maintain the excellent cast aluminum alloy casting capabilities,continuously improve its mechanical properties,expanding its use,is always facing the question of materials workers.In this paper, casting aluminum-silicon alloy based on 702A (Si:6%-8%,Cu:1.2%-1.8%,Mg:0.25%-0.5%,Mn:0.1%-0.2%,Ti:0.05%-0.15%,Sr:0.01%-0.06%),study on strength and toughness of the material.By using the orthogonal experimental method and poor get the best mechanical properties in the case,determined the optimum ratio of alloying elements: Si(6.5%),Cu(1.5%),Mg(0.25%),Mn(0.1%),Ti(0.15%),Sr(0.06%),Fe(≤0.03%).While the melting process of the alloy studied,determine the alloy melt refinement,modification,refined processing technology on organizational performance.The heat treatment process of 702A casting aluminum-silicon alloy is also investigated in this paper. The best heat treatment processing:solution treatment(gradually heating and solution time): 490℃×4h+520℃×6h+540℃×9h+quench;aging: 170℃×9h+air.The T6 heat treatment of 702A casting aluminum-silicon alloy of mechanical properties:σb=355MPa,δ=5.36%.After the optimization of 702A casting aluminum alloy than conventional cast aluminum alloy with superior mechanical properties, can be greater to meet the requirements of moden industrial production an application, has broad application prospects.