论文总字数：16245字

摘 要

搅拌摩擦焊是一种能够比较先进的固相连接技术，它是利用搅拌头与焊件摩擦产生大量的热，是材料成为热塑性状态，随后冷却完成焊接，对异种材料的焊接有着极好的作用。与传统的焊接相比，它焊接时温度比熔焊低，接头的性能好，并且对设备的要求不高，操作简单。本课题对铝铜爆炸焊制备而成的复合板进行搅拌摩擦焊修复，使用金相显微镜、显微硬度仪、电子拉伸机以及扫描电子显微镜对其试样进行了测量与分析。

本次试验的结果有：当轴肩下压量较小时,焊缝由于内部的组织疏松会出现缺陷，如孔洞和隧道型缺陷；当下压量较大时，会有大量飞边的产生。焊核区有较大的孔洞，一方面是因为下压量不够，导致焊缝内部组织疏松，另一方面由于该区域受到较为复杂的搅拌力和摩擦热的作用，成为焊接接头最为薄弱的地方，容易产生缺陷，断裂因此一般多发生在这个区域。搅拌摩擦焊后接头的硬度下降。搅拌焊后焊缝金属的流动性增强，接头成形性好，不易被拉断，力学性能良好。

关键词：搅拌摩擦焊；铝铜复合板；界面组织；力学性能

Effect of Stir Friction Processing on Interface Structure and Mechanical Properties of Aluminum-copper Explosion Welding Dissimilar Metal Clad Plate

Abstract

Friction stir welding is a kind of advanced solid-phase connection technology. It uses the stirring head and the weldment to generate a large amount of friction. It is the material to be in the thermoplastic state, and then it is cooled to complete the welding. It has an excellent effect on the welding of dissimilar materials. Compared with the traditional welding, welding temperature is lower than welding, the performance of the joint is good, and the requirements for the equipment are not high, and the operation is simple. In this project, the composite plate prepared by explosive welding of aluminum and copper was repaired by friction stir welding, and the sample was measured and analyzed using a metallographic microscope, a microhardness tester, an electron stretching machine, and a scanning electron microscope.

The results of this test are: when the amount of pressure on the shoulder is small, the weld will have defects such as holes and tunnel-type defects due to internal looseness of the structure; when the amount of pressure is large, there will be a large number of flashes. There are large holes in the weld zone. On the one hand, because the amount of press down is not enough, the internal structure of the weld is loose. On the other hand, the area is subjected to more complex stirring force and frictional heat, making it the weakest place for welded joints. It is prone to defects and fractures are therefore often found in this area. The hardness of the joint after friction stir welding decreased. The fluidity of the weld metal after the stir welding is enhanced, the joint is good in formability, and it is not easily broken, and the mechanical properties are good.

Keywords: Friction stir welding; Aluminum-copper composite plate; Interface microstructure; Mechanical properties

目录

摘 要 I

Abstract II

目录 III

第一章 绪论 1

1.1搅拌摩擦焊的意义与背景 1

1.2铝铜复合板的背景和加工工艺 2

1.2.1铝铜复合板的背景 2

1.2.2铝铜复合板的加工工艺——爆炸焊 2

1.3铝铜异种金属搅拌摩擦焊接研究现状 3

1.4研究目的及主要研究内容 3

1.4.1.研究目的 3

1.4.2.主要研究内容 4

第二章 实验材料、设备与方法 5

2.1实验材料 5

2.2 实验设备与方法 5

2.2.1 搅拌摩擦焊接实验及设备 5

2.2.2 金相试样的制备与显微组织观察 6

2.2.3 力学性能测试 7

第三章 搅拌摩擦焊接工艺参数对铝-铜爆炸焊复合板的影响 9

3.1 铝-铜爆炸焊复合板界面显微组织分析 9

3.2 搅拌摩擦焊接工艺参数对复合板表面宏观形貌的的影响 9

3.3轴肩下压量对铝铜复合板显微组织的影响 11

3.4 搅拌摩擦焊修复铝铜爆炸复合板力学性能分析 14

3.4.1显微硬度分析 14

3.4.2拉伸性能分析 16

3.5 经济性分析 17

第四章 结论 18

参考文献 19

致谢 21

第一章 绪论

1.1搅拌摩擦焊的意义与背景

转动速度特别快并且匀速移动的搅拌头是搅拌摩擦焊能够焊接的主要因素。组成搅拌头的主要是两个部分，一个是搅拌针，另外一个则是轴肩。图1.1所展示^[1]的便是搅拌摩擦焊的焊接过程。搅拌摩擦焊的工作原理是，当搅拌头快速转动的同时，搅拌针慢慢进入母材需要被焊接的部位，当搅拌头的轴肩与母材表面十分相贴时，搅拌头便开始行进实现焊接。搅拌针在母材相接处快速的转动并与之摩擦，两者在剪切方向摩擦，因此产生剪切摩擦热，同时这个热量会使母材被焊部位软化并且发生塑性变形，塑性流变此时发生在焊缝金属间^[2]。此时，搅拌头仍然沿着焊接方向持续行进，并且快速转动也没有停止。与此同时，摩擦熔化的金属流到搅拌针的尾部并且遇冷凝固形成焊缝，焊接材料的固相连接因此完成^[3]。

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