H.Z. Huang
,
X.Q. Wei
,
L. Zhou
,
null
,
null
金属学报(英文版)
The potential of using a hypoeutectic, instead of eutectic, Sn-Zn alloy as a lead-free solder has been discussed. The nonequilibrium melting behaviors of a series of Sn-Zn alloys were examined by differential thermal analysis. It was found that at a heating rate of 5℃ / min, Sn-6.5Zn exhibited no melting range. Dipping and spreading tests were carried out to characterize the wettability of Sn-Zn alloys on Cu. Both tests exhibited that Sn-6.5Zn has significantly better wettability on Cu than Sn-9Zn. The reaction layers formed during the spreading tests were examined. When the Zn concentration fell between 2.5wt%-9wt%, two reaction layers were formed at the interface, a thick and flat Cu5Zn8 adjacent to Cu and a thin and irregular Cu-Zn-Sn layer adjacent to the alloy. Only a Cu6Sn5 layer was formed when the Zn concentration decreased to 0.5wt%. The total thickness of the reaction layer(s) between the alloy and Cu was found to increase linearly with the Zn concentration.
关键词:
lead-free solder
,
Sn-Zn合金
,
润湿性
,
界面
,
金属间化
陈海燕
,
曾键波
,
谢羽
,
路美秀
,
牛艳
,
李霞
材料工程
doi:10.11868/j.issn.1001-4381.2015.11.010
为保证Sn-Sb-Cu-Ni合金及焊点在低温环境下使用可靠性,将SnSb 4.5CuNi合金焊料和焊点在25,-10,-20,-60℃恒温环境中进行储存565天后,考察了不同温度下SnSb 4.5CuNi合金微观组织形貌、物相、密度、电导率、抗拉强度和塑性的变化,通过纳米压痕法测量SnSb 4.5CuNi/Cu焊点界面过渡层Cu6Sn5金属间化合物(IMC)的硬度和弹性模量,对焊接接头进行抗拉强度、剪切强度和低周疲劳测试.结果表明:合金主要由SbSn和β-Sn组成,低温处理565天后合金组织形貌逐渐转变为树枝状组织,焊料合金的密度和电导率均随温度降低而升高,表明经低温储存后合金没有发生灰锡转变,但脆性SbSn相析出量的增多和枝晶组织致使铸态合金的拉伸强度降低,增加了合金脆断风险;随着温度的下降,焊接界面IMC层的弹性模量和硬度增大,焊件拉伸破坏模式从焊料内部转为IMC层,断口越趋平整,焊件的抗拉强度、抗剪强度下降,呈现了低温脆性断裂的倾向.
关键词:
无铅焊料
,
显微组织
,
低温脆性
,
纳米压痕测试
,
低周疲劳
