Method for making rare earth elements uniformly distributed on surface of aluminum-silicon alloy

Abstract

The invention relates to a method for making rare earth elements uniformly distributed on the surface of an aluminum-silicon alloy, and belongs to the technical field of materials. The method comprises the following steps of: (1) selecting aluminum-silicon alloy cast ingots which comprise the following components in percentage by weight: 12.6 to 25 percent of Si, 0.1 to 2 percent of RE and the balance of Al; cutting cross sections on the aluminum-silicon alloy cast ingots by using a linear cutting method, and grinding and polishing the surfaces of the cross sections; and then cleaning the surfaces with an organic solvent, and removing the organic solvent; and (2) placing the aluminum-silicon alloy cast ingots under the condition of less than or equal to 10<-3>Pa of vacuum degree, and applying high current pulse electron beams to modify the surfaces of the cross sections, wherein the working parameters comprises 23 to 27kV of accelerating voltage and 5 to 25 times of pulse frequency. The method has the advantages of simple process, convenient operation and high energy utilization rate. Tissues quickly fused on the surface of the aluminum-silicon alloy are refined; all the chemical elements are alternatively reallocated; components on the surface are homogenized; and the hardness and toughness can be better matched.

Description

technical field [0001] The invention belongs to the technical field of materials, in particular to a method for uniformly distributing rare earth elements on the surface of an aluminum-silicon alloy. Background technique [0002] Silicon is the main alloying element of aluminum-silicon alloy, which makes the alloy have high fluidity and low shrinkage, so the alloy has excellent casting performance, making aluminum-silicon alloy suitable for manufacturing cylinder heads, pistons, transmission housings, transmissions, Parts such as exhaust pipes have a wide range of application prospects. At present, the aluminum-silicon alloy piston material used in China is mainly eutectic aluminum-silicon alloy. The existence of acicular eutectic silicon, the mechanical properties of the alloy are not high, the tensile strength does not exceed 140MPa, and the elongation δ is less than 3%, which limits the application range of the eutectic aluminum-silicon alloy to a certain extent. In add...

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Problems solved by technology

Gao Bo et al. conducted a preliminary study on the structure changes of eutectic silicon and primary silicon with Nd added, and found that the addition of Nd can refine the silicon phase, but the rare earth element Nd is enriched, and the addition of high content Nd (> 1%) in the casting The resulting alloy microstructure presents a coarse needle-like distribution. This phenomenon will not only limit the expected modification effect of the rare earth element Nd on the alloy, but also the segregation of the Nd element will also affect the properties of the alloy.

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