Zn-containing medium-strength high-ductility die-cast aluminum alloy and preparation method thereof

Abstract

The invention discloses a Zn-containing medium-strength high-ductility die-cast aluminum alloy and a preparation method thereof, and belongs to the field of metal materials. The invention provides a casting aluminum alloy material which is medium in strength, is high in ductility, is free of thermal treatment and is suitable for die-cast formation as well as a preparation method thereof. The medium-strength high-ductility die-cast aluminum alloy consists of the following chemical components in percentage by weight: 10.0-13.0% of Si, 4.1-7.1% of Zn, 0.5-0.8% of Fe, 0.1-0.4% of Mn, 0.02-0.04% ofSr, less than or equal to 0.01% of Mg, less than or equal to 0.01% of Cu, less than or equal to 0.15% of other impurity elements, and the balance of Al. The preparation method comprises the followingsteps: smelting, sampling to rest, regulating alloy components, adding intermediate alloy to refine, de-slagging and casting. Through thermodynamic calculation, content range of Si, Fe and Mn of ternary eutectic Al-Si-Al(FeMn)Si is determined to reduce adverse effects, on alloy plasticity, of Mn and Fe; and Sr is the most common and effective eutectic silicon modifier, so that eutectic silicon ispromoted to convert to fine fibers from thick faller gills, and therefore, alloy plasticity is further improved.

Description

technical field [0001] The invention relates to the field of metal materials, in particular to a Zn-containing medium-strength and high-toughness die-casting aluminum alloy and a preparation method thereof. Background technique [0002] Cast aluminum alloy has the advantages of excellent casting molding and air tightness, low thermal expansion coefficient, good weldability and machining characteristics, and is widely used in automobiles, motorcycles, aerospace, communications and other fields. Among them, the amount of cast aluminum alloy in the automotive field accounts for more than 85% of the total aluminum consumption. Typical components include engine block, cylinder head, clutch housing, oil pan, engine bracket, etc. [0003] At present, cast aluminum alloys mainly include Al-Si series, Al-Cu series, Al-Mg series and Al-Zn series, among which Al-Si series cast aluminum alloys are the most commonly used, accounting for more than 85% of the total aluminum alloy castings....

AI Technical Summary

Problems solved by technology

Among them, the hypoeutectic Al-Si alloy represented by A356 has medium strength and plasticity. After heat treatment, the elongation can reach more than 10%, but due to the low Si content in the alloy (~7%), it is not suitable for die casting. Forming: eutectic Al-Si alloy represented by German SF36 (domestic brand is AlSi10MnMg), has good die-casting performance and comprehensive mechanical properties, die-cast tensile strength is above 230MPa, yield is above 120MPa, and elongation is above 12%. , the application prospect is broad, but the alloy contains a certain amount of Mg, which limits the further improvement of the plasticity of the alloy

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