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The lap joints of Fe-based metallic glass ribbons were carried by resistance spot welding, and the microstructures of spot welds were investigated by X-ray diffraction and transmission electron microscopy. The results indicated that the perfect formations of joints without typical defects such as spatter were achieved with optimized parameters. Except for little nano-particle Fe_2B, no other crystalline particle was detected by TEM, revealing that the most microstructure in spot weld remains amorphous. The maximum tensile-shearing force was 45.0 N with the optimized parameters of 1 kA weld current, 30 N electrode force and 0.02 ms weld time. The spot weld failed as pullout failure mode propagating along the interface of nugget zone. The study demonstrates that resistance spot welding is an effective and practical welding process for Fe-based metallic glass. 相似文献
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通过电磁感应加热装置,研究SAC305/Cu焊点氧化行为和界面金属间化合物(IMC)生长动力学。结果表明,快速热冲击下焊点自身氧化行为是主要因素,内部的Cu6Sn5IMC会加剧焊点的氧化。Cu6Sn5层的生长由晶界扩散控制,Cu3Sn层的生长则由体扩散控制。基底溶解的Cu原子主要扩散到界面IMC和焊料的内部。在快速热冲击下,焊点剪切强度大幅度降低,72 h后下降49.2%。断裂机制由韧性断裂向韧脆性混合断裂转变,最终转变为脆性断裂。 相似文献
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本工作对激光增材制造GH3625(以下简称3D-GH3625)与轧制GH3625进行激光焊接试验,研究激光功率对其焊接接头的显微组织和力学性能的影响,并对其焊接接头的显微组织演变规律进行分析。结果表明,随着激光功率增加,两侧焊缝的熔合区完成由胞状晶向胞状树枝晶转变,而在激光功率相同时,厚板从上到下两侧熔合区的组织形态由上层的柱状晶和胞状晶转变为下层的柱状树枝晶,焊缝中心区由上层的柱状树枝晶和等轴树枝晶转变为下层的柱状树枝晶。当P=5.0 kW,焊接接头无明显表面缺陷、力学性能优良,抗拉强度高达861 MPa,伸长率达到50%左右,对接头断口进行分析,发现断口处有块状MC、部分撕裂棱和孔洞存在。随着激光功率的增加,接头抗拉强度从最高860 MPa下降至833 MPa。 相似文献
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采用硬度测试和透射电镜研究Sn对不同Mg/Si比Al-Mg-Si合金时效硬化与析出行为的影响。结果表明:添加Sn虽然增加了低Mg/Si比合金峰值时效的析出相密度,但也降低了β″相的析出速度,从而降低了低Mg/Si比合金峰时效前的硬化速度和峰时效硬度。过时效阶段,含Sn合金的高析出相密度提高了低Mg/Si比合金过时效硬度。对于高Mg/Si比合金,添加Sn不仅增加合金的析出相密度,同时也提高了β″相的析出速度,从而增加了合金的硬化速度和峰时效硬度。 相似文献