主讲人：Chris Gourlay教授

主讲人简介：Chris Gourlay教授是合金凝固、物理冶金方向的国际专家，现任英国伦敦帝国理工学院材料系物理冶金学教授。至今他已在《自然》《自然‑通讯》《金属学报 (Acta Materialia)》等国际顶级期刊发表 160 篇以上学术论文。其主攻方向为合金凝固相变过程里微观组织的形成机理。近些年，他的课题组围绕钎焊接头、轻质镁铝合金、结构铸件的微观组织演化规律及其调控技术展开研究；同时搭建多项先进试验方案：可控凝固试验、同步辐射‑电镜原位观测、EBSD（电子背散射衍射）以及透射电镜精细表征。他的研究结合基础冶金理论和工程实际，助力新一代金属材料的设计制备工作。

报告摘要：

Title:  “Phase Transformations during Low-Temperature Soldering with Sn-Bi Alloys”

Abstract: As the electronics industry evolves, new processing challenges continually emerge. In the case of larger and thinner electronic packages, a major challenge is dynamic warpage which has triggered a wave of research into developing new low melting temperature solder alloys. Eutectic Sn-Bi solders have emerged as a solution to minimise dynamic warpage and protect temperature-sensitive electronics and these are now used in industry. However, there remain many aspects of microstructure formation and stability that remain incompletely understood. This presentation will give an overview of research in the public domain on the evolution of microstructure during the phase transformations that occur when soldering with Sn-58Bi. The focus is on faceted bismuth crystallisation, tin dendrite growth, the crystallographic aspects of eutectic growth and solid-state precipitation of bismuth during the soldering process.  The approach combines in-situ imaging and diffraction with microstructure analysis after phase transformations. The presentation will highlight the important role of competitive nucleation between the bismuth and tin phases at the start of solidification, and the key role of solid-state bismuth precipitation on microstructure evolution within tin dendrites versus within the eutectic tin. Finally, the differences in bismuth precipitation in Sn-Bi low temperature solders versus in Sn-Ag-Cu-Bi high reliability solders published previously will be discussed.

活动地点：材料科学与工程学院 知远楼A518

活动一 ：学术报告时间：周二，8月18日 10:00-11:00

活动二 ：《凝固原理》系列课程时间：周二、三、四，8月18-20日 14:00-15:00

热烈欢迎各位师生参加交流!