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建立於 2018-03-14, 週三 11:25

最近更新於 2018-05-02, 週三 15:16

發佈於：2018-03-14, 週三 11:32

點擊數：3731

Speaker: Prof. Fuqian Yang

Topic: Effect of Electric Current on Creep Deformation of Tin

March 10  10:30 University of Kentucky, Prof. Fuqian Yang visited and lectured at the College of Engineering (room 236). Interested teachers are welcome to attend.

 

Prof. Fuqian Yang

Department of Chemical and Materials Engineering

University of Kentucky, Lexington, KY 40506

Dr. Fuqian Yang received his B.S. in Engineering Physics from Tsinghua University, M.S. in Mechanical Engineering and Ph.D. in Materials Science and Engineering from the University of Rochester. He is a full professor in the Department of Chemical and Materials Engineering at the University of Kentucky. The primary goal of Dr. Yang's research is to advance the understanding of the fundamental principles of the electrical-chemical-mechanical behavior of materials and to apply them to solve engineering problems. His research focuses on electrical-chemical-mechanical behavior of advanced materials, including creep behavior of materials, adhesive deformation of materials, electromechanical interaction of materials, whisker growth, and stress-diffusion interaction in lithium-ion batteries. His current research activities include energy materials, electrical-mechanical testing of lead-free solders and electronic interconnects, surface engineering of polymer films, modeling and materials characterization of nanostructured materials, and modeling and analysis of batteries.

Effect of electric current on creep deformation of tin

Fuqian Yang

Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, 40506-0046, USA. Email住址會使用灌水程式保護機制。你需要啟動Javascript才能觀看它

ABSTRACT

With the development of electromechanical structures and electronic devices toward the nanometer scale, high current carrying capacity is needed for electronic interconnects and conductor lines. This tendency is true in the future high-power IC chips and power packaging. As a result, electric currents of high current densities can seriously affect device's reliability and potentially cause electromechanical failure of electronic interconnects and conductor lines. The aggressive scaling-down of electronic devices imposes new challenges to understanding the electromechanical response of electronic interconnects and to improving the performance and reliability of micron and nano electronic devices.

This work is focused on the effect of electric current on the creep deformation of tin. The tensile creep of pure tin-strips is performed in the temperature range of 323-423 K and under the stress range from 1.93 to 13.89 MPa. During the tensile creep test under the action of constant load, a direct electric current in the range from 1260.16 to 3780.47 A/cm2 is passed through the sample concurrently. Steady state creep is observed for all the tests. The power law model is used to calculate the stress exponent and activation energy. The steady-state creep velocity increases with increasing temperature and tensile stress. Under the same tensile stress and same chamber temperature, the steady state creep velocity increases linearly with the square of current density. There is no significant effect of electric current on the stress exponent and activation energy for the experimental conditions. The effect of electric current on the surface morphology of the tin-stripes is also examined. The concurrent action of electric current and mechanical loading accelerates the surface damage of the tin-stripes.

Keywords: electric current; creep; activation energy; electronic interconnect; tin.