Creep Behavior Of 63Sn-37Pb Alloy Under The Electro-Mechanical Loadings

63Sn-37Pb alloy has been widely used in the field of electronic packaging, for example the solder joints can provide both mechanical and electrical connection. Therefore the reliability of the solder alloy plays an important role in the packaging structures and the micro-electronic products. In the past few decades, may studies have been carried out on the creep behavior of solder alloy. However, these existing work have mainly focused on the creep behavior of 63Sn-37Pb alloy subjected to the mechanical loads. Few attentions have been paid to the coupling effect of electro-mechanics. With the development of the electronic packaging technology, solder joints at the submicron scale advents in industry which leads to the great density current in solder joints. For this case, the effect of electric current on the performance of 63Sn-37Pb alloy becomes more and more significant in practice.In this work, experiments have been carried out to investigate the creep behavior of 63Sn-37Pb alloy with considering the coupling effect of electric and mechanical loading. Emphasis has been made on the effect of current on the creep exponent and creep activation energy of materials in the exponential law. The main contents of this contribution are as follows:tensile creep experiments of 63Sn-37Pb alloy under the coupling effect of electric and mechanical loadings, in-situ observation of creep behavior of 63Sn-37Pb alloy by digital correlation method, modeling the performance of 63Sn-37Pb alloy under the coupling effect of electro-mechanical loadings.Results indicate that the creep exponent of 63Sn-37Pb alloy will decrease with increasing the electric current, while the creep activation energy will increase with increasing the current density. The applied electric current significantly promotes the surface fold-pattern initiation of 63Sn-37Pb alloy and therefore accelerates the evolution of creep deformation. Microstructure analyses also show that, the electric current will lead to the directional migration of Tin in 63Sn-37Pb alloy. As a result, the staggered lead-depleted zone and lead-rich zone are generated and finally weaken the resistance of creep of 63Sn-37Pb alloy. Meanwhile, the presence of electric current will generate the Joule heat and accelerate the electron migration during the creep process.