论文总字数：17397字

摘 要

1991年，英国研究所通过试验发现了一种新型固相连接技术—搅拌摩擦焊，相比于熔焊，搅拌摩擦焊的效率高、操作过程简便，而且更适合于焊接镁铝合金。5083铝合金是一种铝镁合金，它的可塑性能、力学性能以及耐腐蚀性能都比较好，一般用于制造船舶、汽车、铁路车辆结构。本文研究了5mm厚的5083铝合金搅拌摩擦焊技术，通过使用金相显微镜、显微硬度仪、电子拉伸机以及扫描电子显微镜等设备对接头进行了测量与分析。试验研究了搅拌头转速与焊接速度等参数对5083FSW搅拌头力学性能的影响。当焊接速度为40mm/min，搅拌头转速为1000r/min时获得的接头表面平整、内部无缺陷。增大搅拌头转速或者减小焊接速度会使焊缝热输入过大，形成飞边；减小搅拌头转速或者增大焊接速度会使热输入不足，产生缺陷。在耐腐蚀性方面，焊缝优于母材，而且焊接速度的大小可以影响到所获接头的耐腐蚀性能。将参数控制在合理的范围，5083铝合金搅拌焊接头焊核区的硬度高于母材，且抗拉强度可达母材的91%，这些都表明搅拌焊比熔焊拥有更多的优势。

关键词：搅拌摩擦焊；5083铝合金；力学性能；耐腐蚀性

Analysis of Mechanical Properties and Corrosion Resistance of Friction Welding Joint of 5083 Aluminum Alloy

Abstract

Friction stir welding is a solid-phase joining technique discovered by the British Research Institute in 1991 and is particularly suitable for welding magnesium alloys. 5083 aluminum alloy is an aluminum-magnesium alloy, its plasticity, mechanical properties and corrosion resistance are relatively good, generally used in the manufacture of ships, cars, railway vehicles structure. In this paper, 5mm thick 5083 aluminum alloy friction stir welding technology was studied. The joints were measured and analyzed by using metallographic microscope, microhardness tester, electronic tensile machine and scanning electron microscope. By studying the influence of welding parameters on the mechanical properties of 5083 aluminum alloy FSW joints, it was found that the rotating speed and welding speed of the stirring head have a great influence on the forming quality of the joint. When the welding speed is 40 mm/min and the stirring head speed is 1000 r/min, the joint surface obtained is smooth and free from defects inside. Increasing the rotational speed of the stirring head or reducing the welding speed causes the heat input of the welding seam to be excessively large and causes flashes to form; reducing the rotational speed of the stirring head or increasing the welding speed may result in insufficient heat input and generate defects. In terms of corrosion resistance, the weld seam is better than the base metal, and the welding speed can affect the corrosion resistance of the obtained weld seam. Keep parameters in a reasonable range, the friction stir welding joint of 5083 aluminum alloy has excellent mechanical properties, and the tensile strength can reach 90% of the base metal, which is significantly higher than the traditional fusion welding.

Keywords: Friction stir welding; 5083 Aluminum Alloy; Mechanical properties; Corrosion resistance

目录

摘 要 I

Abstract II

目录 III

第一章 绪论 1

1.1课题研究的背景与意义 1

1.2 5083铝合金的焊接工艺及研究现状分析 1

1.2.1 熔焊研究现状 1

1.2.2 搅拌摩擦焊概述及研究现状 1

1.2.3搅拌摩擦焊工艺 2

1.3研究目的及主要研究内容 3

1.3.1 研究目的 3

1.3.2 研究内容 3

第二章 实验材料、设备与方法 4

2.1实验材料 4

2.2实验设备与装置 4

2.3 分析测试方法 5

2.3.1 金相组织观察 5

2.3.2 显微硬度试验 5

2.3.3 拉伸性能试验 5

2.4 实验工艺及方法 6

第三章 搅拌头转速对5083铝合金搅拌摩擦焊焊缝的影响 8

3.1搅拌头转速对接头表面宏观形貌的影响 8

3.2 搅拌头转速对焊缝微观组织的影响 8

3.2.1焊缝低倍特征 8

3.2.2焊缝组织演变 10

3.3 搅拌头转速对接头力学性能的影响 11

3.3.1 接头显微硬度分布 11

3.3.2接头拉伸性能 11

3.4 本章小结 13

第四章 焊接速度对5083铝合金搅拌摩擦焊焊缝的影响 14

4.1 焊接速度对接头表面宏观形貌的影响 14

4.2焊接速度对接头内部成形的影响 15

4.3 焊接速度对接头性能的影响 15

4.3.1 接头显微硬度分布 15

4.3.2 接头拉伸性能 16

4.3.3 接头耐腐蚀性能 17

4.4 经济性分析 18

4.5 本章小结 18

第五章 结论 20

参考文献 21

致谢 23

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