铜包铝棒材低压充芯制备工艺研究

论文总字数：24713字

摘 要

目前我国乃至世界的铜的资源十分匮乏，进而导致铜的价格较为昂贵且存在价格逐年走高的趋势,这促使电工行业积极寻求代用材料。铜包铝是“以铝代铜”概念的实践之一，截至目前铜包铝材料的制备手段各种各样，每一种都有其特点和局限性。

本文提出了铜包铝棒材的低压充芯工艺技术，以自制的低压充芯设备制备样品，通过宏观观察、显微分析以及界面结合强度、电阻率等性能测试，研究了铝液充芯温度、铜管预热温度、充芯压力、铜管防氧化膜材料以及防氧化膜沉积时间等工艺参数对棒材复合质量、界面过渡层组织、界面结合强度、电阻率等性能的影响，获得了各工艺参数的最佳值，讨论了铜包铝棒材相界面的组织形貌及成分变化与棒材主要性能之间的联系。

在合理的工艺参数范围内，将铝液充入紫铜管中凝固，获得尺寸为Φ12×200mm的圆柱形样品。通过对制备过程和样品质量的宏观观察，发现制备过程中容易产生气孔等缺陷。确定了最佳充芯压力为0.3MPa，选定了K₂ZrF₆作为铜管防氧化膜的制备材料，防氧化膜最佳沉积时间为6min。

对铜铝界面的显微分析结果表明，铜管内壁与铝芯之间存在中间过渡层，形成了良好的冶金结合；充芯温度在720℃—780℃范围内，随着充芯温度的升高，铜铝界面的过渡层厚度逐渐增大；铜包铝棒材的铜铝复合界面处产生CuAl₂和Cu₉Al₄两种金属间化合物，其中前者的含量更高。

性能测试结果表明，铝液充芯温度、铜管预热温度与铜包铝棒材的界面结合强度及电阻率均无线性关系；考虑金属间化合物的影响，740℃是较合适的铝液充芯温度。

关键词：铜包铝；低压充芯；工艺参数；界面相组成；电阻率

Study on the low pressure core filling technology for preparation of copper cladding aluminum rods

Abstract

At present，the copper resources are scarce, resulting in copper prices are more expensive and tend to be price higher year by year, which prompting electrical industry actively seeks alternative materials. Copper clad aluminum composite is a practice of the concept of “Aluminum for copper”. Copper clad aluminum materials so far have many kinds of preparation method, and each has its characteristics and limitations.

Enough samples were made by a homemade low pressure core filling equipment. Technological parameters such as temperature of filling cores, preheating temperature, filling pressure, antioxidant and the deposition time of antioxidant were studied through macroscopic observation, microscopic analysis, and tests of interface bonding strength and resistivity performance. The influence of technological parameters was figured out. And the optimal values of the technological parameters were gotten, while the connections between the main performance and morphologies or compositional variation of phase interface were discussed.

By macroscopic observation, determined the best core filling pressure is 0.3 MPa, selected K₂ZrF₆ as antioxidant, and determined the deposition time of antioxidant is 6 min.

Microscopic analysis showed that the interface formed a good metallurgical combination, and copper has middle transition layer contacting well with aluminum. As the core temperature rises, thickness of interface transition layer is gradually increasing, and the thickness of copper/aluminum diffusion layer increases. The new phases are CuAl₂ and Cu₉Al₄ two kinds of intermetallic compounds; between them the content of the former is higher.

By results of performance test, the temperature of filling core, the preheating temperature and interface bonding strength and resistivity are no linear relationship. Only consider the effect of intermetallic compound, 740℃ is the more appropriate temperature of filling core.

Key words: copper clad aluminum rods; low pressure filling core; technological parameter; interface phase composition; electrical resistivity

目录

1. 绪论………………………………………………………………………………………1

1.1铜包铝材料概述…………………………………………………………………………1

1.2铜包铝材料的研究现状…………………………………………………………………2

1.2.1发展进程…………………………………………………………………………2

1．2．2液-液相复合法…………………………………………………………………2

1.2.2.1充芯连铸法………………………………………………………………3

1.2.3固-固相复合法…………………………………………………………………3

1.2.3.1爆炸焊接法………………………………………………………………3

1.2.3.2包覆焊接法………………………………………………………………4

1.2.3.3静液挤压法………………………………………………………………4

1.2.4液-固相复合法…………………………………………………………………4

1.2.4.1铸造复合法………………………………………………………………5

1.2.4.2电镀法……………………………………………………………………5

1.2.5铜铝界面复合机理………………………………………………………………5

1.2.6铜铝复合界面的影响因素………………………………………………………6

1.3研究意义与目的…………………………………………………………………………7

1.4研究内容…………………………………………………………………………………8

1.5研究技术路线……………………………………………………………………………8

第二章 研究方法…………………………………………………………………………………10

2.1试验材料………………………………………………………………………………10

2.2试验仪器与设备………………………………………………………………………10

2.2.1常规仪器与设备………………………………………………………………10

2.2.2自制低压充芯装置……………………………………………………………10

2.3样品制备方法…………………………………………………………………………11

2.3.1铜防氧化膜的制备……………………………………………………………11

2.3.2铝液熔炼及铜管预热处理……………………………………………………12

2.3.3低压充芯复合工艺参数的确定………………………………………………12

2.4组织与性能测试………………………………………………………………………13

2.4.1棒材质量的宏观观察…………………………………………………………13

2.3.4低压充芯复合过程……………………………………………………………13

2.4.2金相分析………………………………………………………………………13

2.4.3元素分布及相组成分析………………………………………………………13

2.4.4界面结合强度测试……………………………………………………………14

2.4.5电阻率测试……………………………………………………………………14

第三章工艺参数对复合棒材组织与性能的影响………………………………………………16

3.1工艺参数对棒材成形性的影响………………………………………………………16

3.2工艺参数对界面组织的影响…………………………………………………………18

3.2.1金相分析………………………………………………………………………18

3.2.2.1 SEM分析………………………………………………………………20

3.2.2.2 EDS分析………………………………………………………………21

3.2.2.3 EXDA分析………………………………………………………………22

3.2.3 XRD观察分析……………………………………………………………………23

3.3工艺参数对样品性能的影响…………………………………………………………27

3.3.1界面结合强度…………………………………………………………………27

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