|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Metal-Matrix Composites: Advances in Analysis, Measurement and Observations
||In situ Atomic Study of Spontaneous Nanocrystallization of Intermetallic for Interconnection of High-Power and Flexible Electronics
||Ying Zhong, Chunqing Wang, Sungho Jin
|On-Site Speaker (Planned)
A new phase-transformation-induced path to spontaneous formation of extreme nanograin structure is reported. In-situ-heating-mode-microscopy exhibited a substantial grain-growth of Cu6Sn5. During cooling, the grain-growth continued, but it spontaneously switched to grain-refinement mode on phase transformation through ~180 °C from η-Cu6Sn5 to η’-Cu6Sn5, ending up with an extremely small nanograin size of ~2.5 nm. The cooling cycling always restores the nanograin size regardless of thermal exposure history, making this to be the first demonstration to stabilize the nanograin with its own spontaneous behavior. The Young’s Modulus was significantly reduced by ~×3, and the elongation was remarkably increased by ~×8 to ~9%. Nano-Cu6Sn5 interconnection can be obtained at lower temperature than the working temperature, preventing the damage of the flexible substrates and supporting high-power electronics. This work will also inspire other researchers to create many additional sub-4 nm type nanocrystalline intermetallicsand more interesting functions which were difficult to gain before.
||Joining, Characterization, Phase Transformations