Jessica passed her PhD defense! Many Congratulations!
She gave a presentation entitled “Grain size effect on the mechanical properties of Nanocrystalline magnesium aluminum spinel at the microscale“. She discussed how grain size affects hardness, fracture strength, and fracture toughness of Nanocrystalline MgAl2O4, which can be potentially used as a transparent armor. This work has been supported by US Naval Research Laboratory.
Lee’s group attended TMS 2022 at Anaheim, CA!
Three excellent oral presentations were given. Wonderful jobs!
Jessica, Shuyang, and Zhongyuan receives the conference participation award ($1,000) from UConn for their 2022 TMS meeting at Anaheim, CA (February 27 ~ March 3)! Congratulations!
Zhongyuan gave an oral presentation at MRS Fall 2021!
This presentation discusses the unique microstructures created by sequential infiltration of nanoscale oxide into SU-8 negative photoresist, which is used for MEMS structures. These Nanocomposites materials exhibit ultrahigh modulus of resilience (200 MJ/m^3), which is much higher than any other engineering materials. Their high modulus of resilience results from metal-like high strength but polymer-like low Young’s modulus. This unusual combination is potentially useful for developing a strong-but-flexible material that can be used for flexible display.
My two wonderful former graduate students met at California! (Left: Dr. Tyler Flanagan and Right: Dr. Gyuho Song)
I miss CA’s beautiful weather!
Shuyang’s paper was highlighted in the MSE homepage! Congratulations!
Graduate Student Publishes Research on SrNi2P2 Pseudo-elasticity in Nano Letters
Gyuho will leave this Friday to California to start his new position at the Frore Systems. He will work as a material engineer to develop the Micro-electro-mechanical-system (MEMS) device that cools the high performance CPU much faster than the conventional technologies. Best wishes for his success in Silicon Valley!
Shuyang’s first paper is published at Nano Letters! Many congratulations! The paper is now available online [web]. This work discusses the unique pseudoelasticity mechanisms, double lattice and collapse due to the a solid-state bonding and debonding.
Shuyang Xiao, Vladislav Borisov, Guilherme Gorgen-Lesseux, Sarshad Rommel, Gyuho Song, Jessica M. Maita, Mark Aindow, Roser Valentí, Paul Canfield, Seok-Woo Lee, “Pseudoelasticity of SrNi2P2 micropillar via lattice collapse and expansion,” Nano Letters (2021) [Arxiv] [web]
Abstract: The maximum recoverable strain of most crystalline solids is less than 1% because plastic deformation or fracture usually occurs at a small strain. In this work, we show that a SrNi2P2 micropillar exhibits pseudoelasticity with a large maximum recoverable strain of ∼14% under uniaxial compression via unique reversible structural transformation, double lattice collapse–expansion that is repeatable under cyclic loading. Its high yield strength (∼3.8 ± 0.5 GPa) and large maximum recoverable strain bring out the ultrahigh modulus of resilience (∼146 ± 19 MJ/m3), a few orders of magnitude higher than that of most engineering materials. The double lattice collapse–expansion mechanism shows stress–strain behaviors similar to that of conventional shape-memory alloys, such as hysteresis and thermo-mechanical actuation, even though the structural changes involved are completely different. Our work suggests that the discovery of a new class of high-performance ThCr2Si2-structured materials will open new research opportunities in the field of pseudoelasticity.
Gyuho recently received the job offer from the Frore Systems at San Jose, CA, and will work as a materials researcher. Another Silicon Valley engineer after Tyler Flanagan! Good luck for his new adventure!
Tyler will starts his new position at the Evans Analytical Group in CA. Best wishes for his next career!
