【摘要】 制备Al-Cu共晶合金钎料,用SEM和EDS研究不同钎焊温度和保温时间条件下,纯铝棒料基体对接真空钎焊接头Cu元素的扩散行为。结果表明,钎焊温度过低、保温时间过短时,Cu元素在基体内部尚未能充分扩散,在基体晶界上严重偏析,生成Al-Cu相中最脆的θ相(Al2Cu)。提高钎焊温度和保温时间有利于提高Cu元素在Al基体中的扩散效果,但过高的钎焊温度又导致θ相的重新出现,选取最佳的钎焊工艺参数才能获得良好的钎缝质量。更多还原

【Abstract】 The Al-Cu eutectic brazing metal is made to braze pure aluminium substrate in vacuum.The diffusion phenomenon of Cu in pure aluminum bar under different brazing temperature and heat preservation time is investigated by means of SEM and EDS.The results indicate that the diffusion of Cu is not complete at low brazing temperature and short heat preservation time.It comes into being the θ phase（Al₂Cu） which is the brittlest in all Al-Cu phase and forms serious segregation on the substrate′s grain boundary.Although enhancing the brazing temperature and holding time could improve the diffusion effect of Cu,but the exorbitant brazing temperature would cause the reappearance of the θ phase.It is important to choose the best technical parameter for getting the best quality of the welding line.更多还原