铜包铝低压充芯装置改进与导电排制备工艺研究

论文总字数：25732字

摘 要

由于铜资源的匮乏程度愈加严重以及市场价格的一路上升，线缆行业需要积极寻求可以替代铜的材料。铜包铝导电体走进人们视线，虽然目前生产工艺种类繁多，但每一种都存在着局限性。

本文采用低压充芯的工艺方法制备铜包铝导电体，首先对实验室原有低压充芯设备进行改进，并且制备出不同工艺参数下的铜包铝棒材，然后通过轧制工艺将棒材轧制成铜包铝导电排。通过宏观观察、金相分析、扫描电镜微观结构分析以及对界面结合强度、电阻率等性能进行分析测试，对轧制工艺参数进行了研究，分析了铜包铝棒材相界面的组织形貌及成分与棒材主要性能之间的联系，以及铜包铝导电排界面结合情况与轧制工艺的关系，对工艺参数进行了优化。

改进实验装置后，弥补原有设备只能制备小型试验样品的局限性，更有利于将来投入工业生产；并且使能更好控制制备过程的温度，不会在产生较大的温度损失从而影响实验精度；还改进了充芯部位的气密性以及装置的整体气密性，减少了充芯过程中的漏气现象，使充芯压力可以等于充入氮气的压力，参数控制更准确，可制备出缺陷更少、质量更好的棒材。

低压充芯试验结果表明，采用95℃过饱和K₂ZrF₆溶液冷却沉积6min制备出的防氧化膜效果最好，能有效防止铜管内壁在预热过程中氧化，并且在充芯过程可以被迅速分解且无大量气体产生。充芯完成后保压压力设为0.2MPa-0.4MPa 时，制备出的铜包铝棒内部缺陷较少。铝液充芯温度和铜管预热温度是充芯过程中重要的参数，其中充芯温度对铜铝界面过渡层的厚度影响不明显。铜管预热温度升高，过渡层厚度有明显增加，界面的主要金属间化合物为CuAl₂ 和Cu₉Al₄，其中先生成CuAl₂。从界面组织来看，电阻率会随着金属间化合物含量的增加而升高，使导电性能变差。

轧制试验结果表明，轧制过程中，界面处会生成新的过渡层，CuAl₂的生成会降低界面的韧性，导致界面的开裂。因此轧制中需要控制下压量，防止变形量过大导致界面脆性断裂。铜管壁厚为1mm时，轧制过程中极容易开裂。轧制方向与棒材是否平行，也会明显影响铜包铝导电排的界面结合性能。

关键词：铜包铝导电体；低压充芯；轧制工艺；铜铝界面；工艺参数

Study on the improvement of the low pressure core filling equipment and the preparation technology of copper cladding aluminum conductive rows

Abstract

As the lack of copper resources is getting worse, and the copper market price is becoming more expensive. The cable industry needs to actively find a way to replace the copper material. . Copper clad aluminum composite walked into sight. Currently there are a variety of preparation methods, but each of them has its limitations.

This paper proposed a new method, low pressure core filling technology, to produce the copper clad aluminum composite. First，design and improve the existing laboratory equipment, the copper clad aluminum composite samples were made under different process parameters and then the samples were rolled. By macroscopic observation, metallographic analysis, scanning electron microscopy and the test of the interfacial bonding strength, electrical resistivity to analyze the microstructure. The rolling process parameters were studied through the macroscopic observation and metallographic analysis. Finally found the best samples under various process parameters. Analyzed the links between morphology and composition on phase interface and properties of copper clad aluminum rod. Research the effect of the rolling process on interfacial bonding situation.

The preparation of preventing oxidation test results show that the best deposition time of oversaturated K₂ZrF₆ solution of 95℃ is 6 min. The preventing oxidation film can prevent the copper tube from being oxidized effectively in the preheating process, and when the aluminum liquid filling into the copper tube the preventing oxidation film can decompose rapidly and do not produce too much gas.

We selected secondary pressurized mode. When the pressure is 0.2MPa-0.4MPa, prepared copper clad aluminum rod has less internal defects.

Filling temperature of molten aluminum and copper tube preheating temperature were important parameters in the process of filling the core. The thickness of the interfacial transition layer of copper and aluminum do not increase with the filling temperature, but increase with the preheating temperature obviously. The main interface compounds are CuAl₂ and Cu₉Al₄, and CuAl₂ generated firstly.

The interface compounds and the internal defects in copper clad aluminum rod both have influence on electrical resistivity. Therefore, the filling temperature and the preheating temperature have no regularity effect on the changes in electrical resistivity. From the influences of Cu/Al interface, electrical resistivity increases as the interface compounds content increases.

Annealing treatment before rolling and rolling process will generate a new intermediate layer at the interface. The generation of CuAl₂ will reduce the toughness of the interface, lead to cracking interface. It’s necessary to control the amount of depression, to prevent excessive deformation leads to brittle fracture. When copper tube wall thick reduced from 2mm to 1mm. It’s extremely easy to crack in rolling process. The interfacial bonding properties of copper clad aluminum conductive row will be effected if the rods are not parallel to the rolling direction.

Key words: copper clad aluminum rods; low pressure core filling; rolling process; Cu-Al interface; process parameters

目 录

摘 要 I

Abstract II

目 录 IV

第一章 绪论 1

1.1 研究背景 1

1.2 铜包铝复合材料研究现状 2

1.2.1 发展历史 2

1.2.2 制备工艺 2

1.2.2.1 液-液相复合法 2

1.2.2.2 固-固相复合法 3

1.2.2.3 固-液相复合法 4

1.3 铜/铝复合界面 5

1.3.1 复合机理 5

1.3.2 界面组织 6

1.4 研究目的及意义 7

1.5 研究内容 7

1.5.1 待解决的难点 7

1.6 研究思路 8

第二章 低压充芯装置改进 10

2.1 低压充芯工艺 10

2.2 原有装置介绍 10

2.2.1 原有装置功能介绍 10

2.2.2 原有装置的不足 11

2.3 改进装置整体介绍 12

2.3.1 工艺参数 12

2.3.2 改进装置示意图及分析 12

2.4 部件设计说明 13

2.4.1 实验坩埚电阻炉 13

2.4.1.1 坩埚设计 13

2.4.1.2 电阻炉设计 14

2.4.2 铜管预热电阻炉 15

2.4.3 坩埚炉与真空炉的连接装置 16

2.4.3.1 密封材料选择 16

2.4.3.2 连接装置 16

第三章 试验方法 18

3.1 实验材料与设备 18

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