摘 要

隨著鎂合金應(yīng)用的日益廣泛，其焊接接頭的力學(xué)性能也越來越受到人們的重視。當(dāng)前，國內(nèi)外對(duì)鎂合金焊接技術(shù)的研究已經(jīng)取得了較大的進(jìn)展，各種先進(jìn)的焊接技術(shù)日益完善，為鎂合金焊接技術(shù)的發(fā)展提供了廣闊的前景。
本文采用鎢極氬弧焊（TIG）對(duì)AZ61鎂合金進(jìn)行焊接試驗(yàn)，并對(duì)它們的焊接接頭試樣作了微觀組織觀察和試樣拉伸試驗(yàn)，分析了各種焊接因素（焊接電流、焊接速度、有無填焊絲等）對(duì)焊縫成型和焊接質(zhì)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(yàn)機(jī)、X射線衍射儀等設(shè)備對(duì)焊接接頭顯微組織、焊縫相分布、接頭力學(xué)性能等進(jìn)行了分析，并對(duì)焊接過程中氣孔和裂紋產(chǎn)生的原因和防止措施進(jìn)行了討論。試驗(yàn)結(jié)果表明：鎂合金氬弧焊的焊接工藝條件對(duì)焊縫表面形狀及焊縫成型質(zhì)量有很大影響；而焊縫的質(zhì)量又直接影響著鎂合金焊接后的力學(xué)性能。


關(guān)鍵詞：鎂合金，氬弧焊，焊縫，力學(xué)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(yīng)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(diǎn) 3
2 實(shí)驗(yàn) 6
2.1 實(shí)驗(yàn)材料 6
2.2 工藝方案 6
2.3 實(shí)驗(yàn)設(shè)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(yàn)機(jī) 9
2.4 實(shí)驗(yàn)方法 10
2.4.1 試樣制備 10
2.4.2 實(shí)驗(yàn)步驟 11
3 實(shí)驗(yàn)結(jié)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(duì)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(xué)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(xué)性能分析 23
4 結(jié)論 26
參考文獻(xiàn) 27