氧含量对银基粉状钎料润湿性及钎缝力学性能的影响

采用金相显微镜、扫描电镜等分析手段对退火不同时间后的银基粉状钎料进行研究.结果表明,随着氧含量增加,钎料合金的固相线温度不断升高,氧含量为0.6047%的钎料固相线温度比铸态的提高了近56℃;随着氧含量的增加,钎料表层覆盖了大量的氧化物,使钎料和基体之间不能进行良好的润湿,润湿性明显下降;当氧含量增加到0.02%左右时,钎料抗拉强度略有降低,继续增加氧含量,抗拉强度下降速率开始增加,当氧含量增加到0.03%以上时,强度急速下降,由最初的300 MPa左右降低到了170 MPa左右;焊接接头组织中出现夹杂物,而且夹杂物的尺寸随着氧含量的增加不断增大,钎着率降低.

Effect of oxygen content on wettability and mechanical property of brazing seam for silver based powdered brazing filler metal

The properties of silver brazing filler metal with different oxygen content were studied by optical microscope, scanning electron microscopy and other analytical tools. The results of the experiment indicate that with the increase of oxygen content,the melting point of the solder alloy rises,which is 56℃ higher than that is casted when oxygen content is 0.6047%. With increase of the oxygen content,the surface layer of the brazing filler metal was covered with much oxide,the wetting ability between the solder and the substrate significantly decreases. When the oxygen content is about 0.02%,the tensile strength of the brazing filler metal is lowered slightly. When the oxygen content increases to more than 0.03%,the tensile strength decreases from over 300 MPa to about 170 MPa. The size of the inclusions in the welded joint increases with the oxygen content increases, while the brazed rate decreases.