Ni含量对304/Sn-8Sb-4Cu-xNi/304钎焊接头组织与剪切性能的影响

Effect of Ni content on microstructure and shearing property of 304/Sn-8Sb-4Cu-xNi/304 solder joints

研究了Ni含量对Sn-8Sb-4Cu-xNi(x=0,0.5,1和2,质量分数)钎料熔点和微观组织的影响,用Sn-8Sb-4CuxNi钎料对304不锈钢进行钎焊连接,分析了接头的界面组织与剪切性能.结果表明,添加不同含量的Ni后,Sn-8Sb-4Cu-xNi均为近共晶钎料,其熔点约为245℃;Sn-8Sb-4Cu钎料组织由α相基体、Sb_(2)Sn_(3)+Cu_(6)Sn_(5)+Sn复合相和Cu_(6)(Sn,Sb)_(5)相组成.添加Ni元素后,钎料中块状Cu_(6)(Sn,Sb)_(5)转变为细小、均匀分布的(Cu,Ni)_(6)(Sn,Sb)_(5).当Ni含量小于1%时,随Ni含量的增加,钎料中的复合相和(Cu,Ni)_(6)(Sn,Sb)_(5)相均增加;当Ni含量为2%时,钎料中的复合相和(Cu,Ni)_(6)(Sn,Sb)_(5)相均减少,但(Cu,Ni)_(6)(Sn,Sb)_(5)相中Ni含量增加至与Cu相当;Sn-8Sb-4Cu-xNi/304钎焊界面均形成了一层厚度约1.5μm的扩散反应层,EDS分析显示,该层为FeSn_(2)化合物.钎缝中全部为Cu_(6)Sn_(5)型化合物,未见Sn-Sb型化合物.Ni元素的添加,提高了304/Sn-8Sb-4Cu-xNi/304钎焊接头的抗剪强度,当Ni含量为0.5%时,接头抗剪强度最大,为67 MPa,与不含Ni钎料相比提高了60%.所有接头的断裂位置均位于钎缝.

Effect of Ni content on melting point and microstructure of Sn-8Sb-4Cu-xNi(x=0,0.5,1 and 2,mass fraction)solders were investigated.304 stainless steel were joined by Sn-8Sb-4Cu-xNi solders,and interfacial microstructure and shearing property of the solder joints were analyzed.The results showed that all of the Sn-8Sb-4Cu-xNi with different Ni content are near eutectic solders,with a melting point of 245℃.The microstructure of Sn-8Sb-4Cu solder was consisted ofαphase,Sb_(2)Sn_(3)+Cu_(6)Sn_(5)+Sn composite phase and Cu_(6)(Sn,Sb)_(5)phase.After the addition of Ni,the bulk Cu_(6)(Sn,Sb)_(5)transformed into fine and uniformly distributed(Cu,Ni)_(6)(Sn,Sb)_(5).When Ni content was less than 1%,the amount of composite phase and(Cu,Ni)_(6)(Sn,Sb)_(5)phase increased with the increasing of Ni content.When Ni content increased to 2%,the amount of composite phase and(Cu,Ni)_(6)(Sn,Sb)_(5)phase decreased with the increasing of Ni content,however,Ni content in the(Cu,Ni)_(6)(Sn,Sb)_(5)phase increases to be comparable to Cu.A diffusion layer with a thickness of about 1.5μm formed at the Sn-8Sb-4Cu-xNi/304 interface,which was identified to be Fe2Sn by EDS.Only Cu_(6)Sn_(5)type intermetallic compounds formed in the solders of 304/Sn-8Sb-4Cu-xNi/304 joints.The addition of Ni element improved the shear strength of 304/Sn-8Sb-4Cu-xNi/304 brazed joints,and the maximum shear strength of 67 MPa was achieved when the Ni content was 0.5%,which was 60%higher compared to the Ni-free brazing material.The shear fracture locations of all joints were located in the soldering seam.