摘 要

隨著鎂合金應用的日益廣泛，其焊接接頭的力學性能也越來越受到人們的重視。當前，國內外對鎂合金焊接技術的研究已經取得了較大的進展，各種先進的焊接技術日益完善，為鎂合金焊接技術的發(fā)展提供了廣闊的前景。
本文采用鎢極氬弧焊（TIG）對AZ61鎂合金進行焊接試驗，并對它們的焊接接頭試樣作了微觀組織觀察和試樣拉伸試驗，分析了各種焊接因素（焊接電流、焊接速度、有無填焊絲等）對焊縫成型和焊接質量的影響及其規(guī)律。利用金相顯微鏡、電子掃描顯微鏡、萬能材料試驗機、X射線衍射儀等設備對焊接接頭顯微組織、焊縫相分布、接頭力學性能等進行了分析，并對焊接過程中氣孔和裂紋產生的原因和防止措施進行了討論。試驗結果表明：鎂合金氬弧焊的焊接工藝條件對焊縫表面形狀及焊縫成型質量有很大影響；而焊縫的質量又直接影響著鎂合金焊接后的力學性能。


關鍵詞：鎂合金，氬弧焊，焊縫，力學性能，缺陷


















ABSTRACT

The mechanical property of welding magnesium alloy is one of the major concerns in the development of magnesium alloy be used in industry. Recently, research on the welding of magnesium alloy makes a great progress and the new advanced welding techniques which be used in industry promoted the further development of magnesium alloy welding techniques.
In this study, the influence of gas tungsten arc (TIG) welding parameters (such as welding current, welding speed and welding wire) on the microstructures and mechanical properties of AZ61 magnesium alloy welded joints was investigated. Microstructure was characterized by optical microscopy and scanning electron microscopy. X-ray diffraction was adopted for the determination of phase structure in alloy. Mechanical properties were determined by standard tensile tests. Furthermore, the intrinsic mechanism of the formation of porosity and cracking in welded joints was discussed in detail. The results indicate that the formation of welding seam and their qualities were influenced by the welding parameters, and then the achieved welding seam influenced the mechanical properties of magnesium alloy welding joint strongly.


Key words：magnesium alloy, TIG, welding seam, mechanical properties, welding defects














目 錄

中文摘要 Ⅰ
ABSTRACT Ⅱ
1緒論 1
1.1鎂合金的性能及應用 1
1.2鎂合金的焊接 2
1.2.1 鎂合金的焊接特性 2
1.2.2 鎂合金氬弧焊(TIG)及其特點 3
2 實驗 6
2.1 實驗材料 6
2.2 工藝方案 6
2.3 實驗設備及其原理 7
2.3.1 掃描電子顯微鏡 7
2.3.2 萬能材料試驗機 9
2.4 實驗方法 10
2.4.1 試樣制備 10
2.4.2 實驗步驟 11
3 實驗結果及分析 12
3.1鎂合金氬弧焊焊接接頭的微觀組織觀察 12
3.1.1 AZ61鎂合金焊接接頭微觀組織 12
3.1.2 焊接工藝對接頭組織與性能的影響 15
3.1.3 焊縫成分分析 18
3.2 AZ61鎂合金氬弧焊接頭焊接缺陷的分析 20
3.2.1 氣孔 20
3.2.2 裂紋 22
3.3氬弧焊接接頭的力學性能分析 23
3.2.1焊接接頭顯微硬度測試及分析 23
3.2.2焊接接頭拉伸力學性能分析 23
4 結論 26
參考文獻 27