Homogenization heat treatment method of as-cast zinc-aluminum alloy material

Abstract

The invention discloses a homogenization heat treatment method of an as-cast zinc-aluminum alloy material, which comprises: performing the homogenization heat treatment of a cast ingot which comprises 25.0 to 28.0 weight percent of Al, 2.0 to 2.5 weight percent of Cu, 0.015 to 0.020 weight percent of Mg, less than 0.07 weight percent of Fe, less than 0.04 weight percent of Pb, less than 0.003 weight percent of Cd, less than 0.002 weight percent of Sn and the balance of Zn at a heating temperature of 330 to 360 DEG C, keeping the temperature for 8 to 24 hours and cooling the cast ingot with the furnace. In the invention, the technical method is simple; the operation is convenient; the uniformity of the structural constituents of the zinc-aluminum alloy casting is improved effectively, and the plasticity and size stability of the zinc-aluminum alloy casting are improved; by improving the solid solution degree of the Cu element in a substrate, the size and performance stability of the material are improved; the dendritic segregation and unbalance eutectic phase are improved to a maximum degree, the uniformity of the material structure is improved and the plasticity of the alloy is improved; and the method is suitable for industrial production, and can improve the mechanical performance of the as-cast aluminum alloy and expand the application range of the as-cast aluminum alloy.

Description

technical field [0001] The invention discloses a method for homogenizing heat treatment of as-cast zinc-aluminum alloy materials, belonging to the technical field of heat treatment of metal materials. Background technique [0002] ZA27 alloy is a zinc-aluminum alloy containing 25.0-28.0wt% Al. Due to its high tensile strength and hardness, good damping performance, good wear resistance and friction reduction performance, and good machinability , and low melting point, low smelting energy consumption, high production efficiency, low manufacturing cost, so people pay more and more attention to it. At present, it is widely used in industrialized countries such as the United States, Canada, Germany, Britain, Japan, Russia, etc., and the most widely used It is to replace bronze alloy as wear-resistant material, or replace aluminum and cast iron as die casting. So far, zinc-aluminum alloy materials have been successfully used in various bearing bushes, bushings, turbines, nuts fo...

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Problems solved by technology

In addition, due to the Cu-rich metastable ε phase at the grain boundary of the as-cast structure, a four-phase reaction of α+ε→T′+η will occur during the natural aging process to form a stable T′ phase, which will lead to obvious The volume expansion of the alloy reduces the dimensional stability of the alloy, and the Cu-rich phase at the grain boundary can also lead to intergranular corrosion

At present, the heat treatment method commonly used for ZA27 alloy is 230-250 ° C for 3 hours and then air cooling. Due to the low heat treatment temperature, the dendrite segregation and non-equilibrium eutectic phase of the alloy cannot be completely eliminated, and the plasticity and toughness still cannot meet the requirements.

However, there is no report on the homogenization heat treatment process of as-cast ZA27 alloy

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