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摘要本论文以6061铝合金、45钢螺柱和Al-Si钎料为研究对象，对45钢螺柱采用不同金属镀层技术，进行了各种钎焊试验，着重在真空条件下开展铝钢异种金属螺柱钎焊工艺的试验研究，分析钎焊接头的力学性能和微观组织。探索真空钎焊下45钢、镀层、Al-Si钎料、6061铝合金四种物质间的结合原理以及钎焊温度、保温时间、镀层材料对钎焊接头的影响。9844
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本课题研究结果如下：
（1）在高频感应加热钎焊试验过程中，镀Ag螺柱生成的接头性能最好，生成的金属间化合物硬度比钢还低，脆性大大降低了。
（2）在铝-钢真空钎焊试验过程中，钎焊温度、保温时间是真空钎焊方法下影响铝-钢接头质量的关键因素。过渡层有Fe-Al，Fe-Ag-Al等金属间化合物、针状的Al-Si共晶组织、Fe-Si化合物以及α-Al固溶体新相生成。其中三金属间化合物的生成有效地降低Fe-Al金属间化合物的硬度，得以降低接头的脆性。
关键词：6061铝 45钢 真空钎焊 过渡层 Fe-Al金属间化合物
毕业设计说明书（论文）外文摘要
Title Study on Vaccum Brazing technique for Dissimilar Metal
between Aluminum and Steel Stud based on middle layers
Abstract
In this paper, the weldability of dissimilar metal between 45 steel stud with different metal coatings and 6061 aluminum alloy was studied by using Vaccum Brazing Welding.Content of this paper was to conduct kinds of welding process tests in the vaccum conditions, observe brazed joints' microstructure characteristics and analysis mechanical properties.The issue's point was to discover the combination principle of the 45 steel,coating, Al-Si brazing filler metal and the effect of the weld parameter and different middle layers.
The graduate project results were showed as follows.
In the high frequency induction brazing test process, Ag coating did best to dissimilar metal joint's mechanical properties as the intermetallic hardness was highly decrease.
In the vaccum brazing test, brazing temperature and thermal insulation time were the key factor influencing the test quality.
Research on middle layer.The middle layer consisted of Fe-Al, Fe-Ag-Al intermetallic compounds, Al-Si eutectic microstructure like needle, Fe-Si compounds and α-Al solid solution, etc. Fe-Ag-Al intermetallic compounds was able to neutralize the high brittleness of Fe-Al compounds.
Keywords: 6061Al 45#Fe coatings vaccum brazing
Fe-Al intermetallic compounds
目录
1 绪论 1
1.1选题的背景及意义 1
1.2国内外螺柱焊接技术的发展现状 2
1.3异种金属界面复合理论 4
1.4铝钢异种金属焊接难点 5
1.5本课题研究的主要内容 7
2 试验材料与设备 8
2.1试验材料 8
2.2试样加工 8
2.3试样表面处理 9
2.4试验设备和研究器材 9
3 试验工艺方案设计 13
3.1镀层的选择 13
3.2钎料与母材的相互作用 13
3.3铝-钢高频感应钎焊工艺设计 15
3.4铝-钢SOYER螺柱焊 18
3.5铝-钢TIG焊+钎焊 19
4 铝-钢真空钎焊 21
4.1真空钎焊的优势 21
4.2试验方案设计 21
4.3真空加热操作过程 23
4.4真空钎焊试验力学性能测试 24
4.5接头宏观形貌特点分析 25