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为了降低铍焊缝的缺陷,提高焊接接头的强度,本文针对所研制的高纯铝硅钎料,采用高温拉伸试验、SEM扫描、能谱分析等分析手段,分析研究了其高温力学性能、组织特征和钎焊接头的成分分布,探讨了焊接缺陷形成机制。结果表明,冷却速率通过改变初生α-Al相和共晶β-Si相的形态进而影响到材料的力学性能,冷却速率增加,共晶β-Si相变细,相间距减小,材料的热塑性提高。焊缝部位的SEM及能谱分析结果显示,裂纹部位的C、O、Ca等杂质元素含量偏高,尤其是BeO在晶界的偏析严重,这些脆性相在晶界处聚集,导致局部区域塑性降低。
In order to reduce the defects of beryllium welds and improve the strength of welded joints, aiming at the high purity Al-Si brazing filler, the high-temperature tensile test, SEM scanning and energy spectrum analysis were used to analyze the mechanical properties at high temperature, Organizational characteristics and the composition of brazed joints distribution, discussed the welding defect formation mechanism. The results show that the cooling rate can affect the mechanical properties of the material by changing the morphology of the primary α-Al phase and the eutectic β-Si phase. The cooling rate increases, the eutectic β-Si phases become smaller, the phase spacing decreases, improve. The results of SEM and EDS showed that the content of C, O, Ca and other impurity elements in the cracked part were high, especially the segregation of BeO in the grain boundary was serious. These brittle phases were aggregated at the grain boundary, resulting in the plasticity of the local region reduce.