Epsilon phase modification agent in zinc-copper alloy and modification method

A technology of copper alloy and modifier, applied in the field of alloy materials, to achieve the effects of convenient operation, reduced grain size, and increased number of crystal nuclei

Inactive Publication Date: 2018-12-18
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, few effective methods for modifying ε-phase dendrites in Zn-Cu alloys are currently available.

Method used

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  • Epsilon phase modification agent in zinc-copper alloy and modification method
  • Epsilon phase modification agent in zinc-copper alloy and modification method
  • Epsilon phase modification agent in zinc-copper alloy and modification method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The modification treatment method of ε-phase dendrites in the Zn-8Cu alloy (the mass percentage of Cu in the alloy is 8%, and the liquidus temperature is about 530°C), the specific steps are as follows.

[0033] (1) Melt the Zn-8Cu alloy to 590°C to obtain a Zn-8Cu alloy melt.

[0034] (2) Add a certain amount of pure bismuth into the above melt so that the mass percentage of bismuth element in the alloy is 0.5%, and then stir the melt.

[0035] (3) After 8 minutes, stir the alloy melt again to make the bismuth element evenly distributed in the melt. Then the above melt is poured into the mold, and the modified zinc-copper alloy is obtained after cooling.

[0036] In this example, before the Zn-8Cu alloy is modified, the ε phase branches are well developed, and the size of the primary dendrite is more than 200 μm, and the primary dendrite contains a large number of secondary dendrites (the size can reach more than 100 μm) and a small amount of tertiary dendrites ( fig...

Embodiment 2

[0038] The modification treatment method of the epsilon phase dendrite in the Zn-8Cu alloy (the mass percentage of Cu in the alloy is 8%), the specific steps are as follows:

[0039] (1) Melt the Zn-8Cu alloy to 615°C to obtain a Zn-8Cu alloy melt.

[0040] (2) Add a certain amount of pure bismuth into the above melt, so that the mass percentage of bismuth element in the alloy is 0.1%, and stir to make the bismuth element evenly distributed in the melt.

[0041] (3) Then pour the above melt into a mold, and obtain a modified zinc-copper alloy after cooling.

[0042] In this example, before the modification of the Zn-8Cu alloy, the ε phase branches are developed, and the size reaches more than 200 μm. After the modification by the method of this example, the ε phase grain branches are obviously suppressed and reduced, and the size is only about 70 μm ( image 3 ).

Embodiment 3

[0044] The modification treatment method of the epsilon phase dendrite in the Zn-8Cu alloy (the mass percentage of Cu in the alloy is 8%), the specific steps are as follows:

[0045] (1) Melt the Zn-8Cu alloy to 600°C to obtain a Zn-8Cu alloy melt.

[0046] (2) Add a certain amount of pure bismuth into the above melt, so that the mass percentage of bismuth element in the alloy is 1%, and stir to make the bismuth element evenly distributed in the melt.

[0047] (3) Then pour the above melt into a mold, and obtain a modified zinc-copper alloy after cooling.

[0048] In this example, before the Zn-8Cu alloy is modified, the ε phase branches are developed, and the size reaches more than 200 μm. After the modification by the method of this example, the ε phase grain branches are significantly reduced, and the size is only about 90 μm ( Figure 4 ).

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Abstract

The invention provides an epsilon phase modification agent in a zinc-copper alloy. The modification agent is bismuth with the purity of 99.10wt.%-99.99wt.% or a zinc-bismuth intermediate alloy with bismuth content of 10%-30% by mass. A small amount of the modification agent is added and a good modification treatment effect can be obtained, a method for modification treatment is provided, only thetemperature needs to be raised and the modification agent is added in the treatment process, the growth of the epsilon phase can be restrained, the number of crystal nucleus of the epsilon phase is increased, the grain size of the epsilon phase is reduced, branches of the epsilon phase are reduced, and the epsilon phase is more evenly distributed in an alloy matrix.

Description

technical field [0001] The invention belongs to the technical field of alloy materials, and in particular relates to a modifier and a modification method for the ε phase (copper-zinc compound) in a zinc-copper alloy. Background technique [0002] Zinc-copper alloy has good machinability and mechanical properties, and has good application prospects in the field of structural materials such as hardware and auto parts. The matrix of such alloys consists of η-Zn and ε phase (copper-zinc compound) grains. However, when the mass percentage of copper exceeds 1.7%, especially when it is 3-10%, the ε phase nucleates directly from the liquid phase when the zinc-copper alloy is solidified, then grows rapidly and freely, and finally grows into well-branched and large-sized dendrites. The generation of developed dendrites will bring a series of quality problems to zinc-copper alloys, such as: shrinkage porosity and pores are easy to remain in the structure, resulting in microscopic com...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/02C22C1/06C22C18/02
CPCC22C1/02C22C1/06C22C18/02
Inventor 王振卿郑锴王英姿赵德刚左敏
Owner UNIV OF JINAN
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