SiCp/2024AlMMC颗粒暴露及钎焊行为分析
Analysis of exposed particles and mechanical performance of brazing joints of SiCp/2024Al composites
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摘要: 介绍了焊接参数对SiCp/2024Al铝基复合材料的真空钎焊组织和性能的影响.焊前利用颗粒暴露技术将复合材料表面颗粒部分暴露,并利用真空气相沉积使暴露表面合金化.使用M6钎料,在不同的钎焊工艺参数下对复合材料进行焊接.结果表明,焊接温度过低或者保温时间过短,钎缝结合面有残留的Cu,钎料对复合材料润湿不好.随钎焊温度增加,保温时间的进一步延长,Cu与Al基体完全反应,促进了钎焊过程.但随着钎焊温度和保温时间的进一步增加,母材中出现过烧导致的气孔.钎焊接头X射线衍射试验表明,接头中没有Al4C3脆性相生成.拉伸试验表明,钎焊参数为620℃,保温20min时,接头抗剪强度最高,达到202MPa.断口分析表明,钎料对复合材料的不润湿,复合材料过烧导致气孔,复合材料中颗粒的聚集是导致接头强度下降的主要原因.Abstract: The effect of brazing parameters on the vacuum-brazing microstructure and mechanical performance of SiCp/2014Al aluminum matrix composite(MMC) was studied.The SiC reinforcements on the parent composite surface were exposed by the surface reinforcement exposing technique,and then Cu was deposited on the parent matrix composite.By using M6 aluminum alloy as the filler metal,the parent composites were brazed under several different parameters.The test results show that if the brazing temperature is lower or the keeping time is shorter,there is Cu retained on MMC surface.With the increasing of brazing parameters(brazing temperature and keeping time),Cu reacts with Al base metal completely.If the brazing parameters are too high,the porosities by over-burning appear in the base metal.X-ray diffractometry analysis indicates that there is no Al4C3 brittle phase formed in the brazing joint.The tensile test indicates that the strength of the joint is 202 MPa at brazing temperature 620℃ and keeping time 20 min.The fractography of the brazing joint indicates that the filler metal is un-wetting to the parent composite,the porosities in the parent composite and the aggregated particles in the parent composite are the reasons for the joint cracking.