|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Late News Poster Session
||C-5: Effect of Antimony on the Microstructure Evolution and Mechanical Properties of Near Eutectic Sn-Bi and Sn-Bi-Ag Alloys
||Hannah Fowler, Raiyo Aspandiar, Yaohui Fan, Sukshitha Achar Puttur Lakshminarayana, Ganesh Subbarayan, John Blendell, Carol Handwerker
|On-Site Speaker (Planned)
Eutectic and near-eutectic Sn-Bi alloys are promising low-temperature replacements for some high-Sn Pb-free solder applications, allowing reflow temperatures to be reduced by 70˚C relative to Sn-Ag-Cu alloys, the most commonly used Pb-free solder. Low-temperature reflow using eutectic Sn-Bi can reduce component warpage and eliminate a range of warpage-induced solder joint defects, including head-on-pillow defects. First generation near-eutectic Sn-Bi alloys show excellent thermal cycling reliability but poor drop-shock performance. Small additions of Sb to Sn-Bi and Sn-Bi-Ag eutectic alloys can significantly increase ductility and reduce strain-rate sensitivity without decreasing the yield strength, combinations shown to improve shock-drop performance. In this presentation, we will discuss the impact of Ag and Sb additions on solidification and microstructure evolution in eutectic Sn-Bi alloys on Cu and ENIG substrates and how the resulting compositions and microstructures affect solder joint mechanical properties, particularly isothermal mechanical fatigue and crack path, and relate this behavior to drop-shock testing.
||Mechanical Properties, Electronic Materials,