A high-strength plastic casting hypoeutectic aluminum-silicon alloy and its preparation method

Abstract

The invention develops a high-strength plastic casting hypoeutectic aluminum-silicon alloy and a preparation method thereof, belonging to the field of metal materials. The high-strength plastic casting hypoeutectic aluminum-silicon alloy consists of the following components in terms of mass percentage: Si: 7.0-8.0wt.%, Cu: 1.0-2.5wt.%, Mg: 0.40-0.50wt.%, Mn : 0.25~0.35wt.%, B: 0.020~0.035wt.%, Sb: 0.1~0.2wt.%, Zn: 0.60~0.80wt.%, unavoidable impurity content ≤ 0.2wt.%, the balance is Al . Its preparation method includes: after the aluminum ingot, Al-20Si, Al-10Mn and Al-50Cu alloys are completely melted, adding Al-3B, Mg, Zn and Sb in sequence, and casting to obtain a high-strength plastic casting hypoeutectic aluminum-silicon alloy . By adding B, Sb and Zn to the aluminum-silicon alloy, the alloy obtained by the present invention synergistically regulates the microstructure and morphology of the alloy, and at the same time has the integrated effect of refinement and modification, and significantly improves the mechanical properties of the alloy. The yield strength, tensile strength and elongation of the high-strength plastic casting hypoeutectic aluminum-silicon alloy obtained in the present invention are respectively 150MPa, 281MPa and 9.3%.

Description

technical field [0001] The invention belongs to the field of metal material processing, and in particular relates to a high-strength plastic casting hypoeutectic aluminum-silicon alloy and a preparation method thereof. Background technique [0002] Cast hypoeutectic Al-Si alloy has the advantages of good fluidity and formability, and good comprehensive performance. It is widely used in the production of key parts in the fields of automobiles, aerospace and other fields in actual production. Among them, the as-cast microstructure and properties of the cast hypoeutectic Al-Si alloy are particularly important. However, in the as-cast structure of common cast hypoeutectic Al-Si alloys, there is a phenomenon that the α-Al dendrite size is large and the eutectic Si is in the shape of long needles or slender plates, which seriously affects the strength and plasticity of the alloy. . At present, Al-5Ti-B refiner is often used to refine α-Al in cast hypoeutectic Al-Si alloys, but s...

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Problems solved by technology

Although Na modification has a good modification effect, it is prone to decay and failure, and it is easy to produce smog to pollute the environment during the addition process; although Sr modification has the advantages of obvious modification effect and long-term effect, it has a long incubation period of modification, serious inhalation tendency, and serious burning loss. , the tissue is prone to defects such as pores and shrinkage

[0003] In summary, in view of the problems of coarse α-Al dendrites and poor modification effects of Na, Sr and other modifiers in the current cast hypoeutectic Al-Si alloy, how to develop a low-alloy alloy that has both refinement and modification effects Cost alloy is a technical problem that needs to be solved urgently

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