Lee group attended the ECI Nanomechanical Testing in Materials Research and Development VII at Malaga, Spain!

The following presentations were given by my group.

• Gyuho Song: Superelasticity of ThCr₂Si₂-structured intermetallic compounds at the micrometer scale (oral)
• Gyuho Song: Micromechanical characterization of single-crystalline niobium at low temperature (poster)
• Tyler Flanagan: Nanoindentation properties of shock compressed single crystal magnesium (poster)
• Jessica Maita: Atomic arrangement and mechanical properties of chemical vapor deposited amorphous boron (poster)

 

(If you click an image, you can see its large image.)

 

Hetal’s paper was published at Scripta Materialia! Congratulations!

Hetal D. Patel, Seok-Woo Lee, “Spherical indentation on tungsten single crystal: transition from source-controlled plasticity to bulk plasticity,” Scripta Materialia, 175, 16-19 (2019) [PDF] [web]  – Hetal D. Patel (undergraduate student)

Hetal has worked at the Lee group nearly for her entire undergraduate time, and finally got a publication! She recently started her PhD degree at MSE in UC Berkeley. I wish Hetal a success!

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ABSTRACT

Spherical nanoindentation was performed on tungsten single crystal to investigate the effects of tip radius on the pop-in stress. The results show that the pop-in stress decreases as the tip radius increases. A statistical model with randomly distributed dislocation sources captures experimentally observed source-controlled indentation size effect. The discrepancy between model and experimental data especially for a large tip was corrected by considering the collective activation of multiple dislocation sources. Our results provide a quantitative insight into the understanding of the transition from source-controlled plasticity to bulk plasticity under spherical nanoindentation.

Gyuho and Tyler receive the UConn doctoral student travel fellowship! Congratulations!

The detailed information of the doctoral student travel fellowship is available at the link below.

https://grad.uconn.edu/financing/fellowships/travel-fellowship/

 

 

Profs. Ying Li (Mechanical Engineering, UConn) and Seok-Woo Lee (Materials Science and Engineering, UConn) receives the NSF-MoMS (Mechanics of Materials and Structures) fund, $600,000 for 01/01/2020~12/31/2022.

The title of project is “Unrevealing Mechanics of Anomalous High Strength and Low Stiffness in Polymer Nanocomposites“. This project will investigate the fundamental origin of high strength and low Young’s modulus of sequential-infiltration-synthesized polymer nanocomposites using the advanced computer simulation and in-situ nanomechanical testing system. Polymer synthesis will be done by collaborating with Dr. Chang-Yong Nam at the Center for Functional Nanomaterials of Brookhaven National Laboratory.

Tyler passed his PhD proposal defense! Many congratulations!!!

Tyler has worked on micromechanical behavior of metallic microparticles. His current research focuses are micromechanical behavior of supersonic impacted Al6061 microparticles. This work is currently supported by U.S. Army Research Laboratory.

Tyler’s Au microparticle paper was published at Scripta Materialia! Congratulations!

This work studied the transition of deformation mode (dislocation nucleation vs. single arm source) using microcompression and statistical modeling. Au microparticles were provided by Prof. Eugen Rabkin’s group at Technion, Israel.

Surprisingly, Tyler has two Scripta Mater papers (the first author for both) in the same volume! Awesome!

Tyler J. Flanagan, Oleg Kovalenko, Eugen Rabkin, Seok-Woo Lee, “The effect of defects on strength of gold microparticles,” – Scripta Materialia, 171,  83-86 (2019) [PDF] [web]

 

Another Scripta one is the following.

Tyler J. Flanagan, Benjamin Bedard, Alex Ernst, Avinash M. Dongare, Seok-Woo Lee, Harold D. Brody, Victor K. Champagne Jr, Mark Aindow, “Mechanical properties of supersonic-impacted Al6061 microparticles,” – Scripta Materialia, 171, 52-56 (2019) [PDF] [web].

Seok-Woo gave an invited talk at NANO KOREA 2019 at KINTEX, South Korea. The title of his talk was “Superelasticity in ThCr2S2-structured intermetallic compounds and their hybrid structures.” This talk summarized all results of superelasticity research that his group has worked on for the last four years.

 

1. Gyuho Song, Vladislav Borisov, William R. Meier, Mingyu Xu, Keith J. Dusoe, John T. Sypek, Roser Valenti, Paul C. Canfield, Seok-Woo Lee*, “Ultrahigh elastically compressible and strain-engineerable intermetallic compounds under uni-axial mechanical loading,” APL Materials 7, 061104 (2019) [PDF] [web]

2. Ian N. Bakst, Keith J. Dusoe, Gil Drachuk, James R. Neilson, Paul C. Canfield, Seok-Woo Lee, Christopher R. Weinberger, “Effects of point defects on the mechanical response of LaRu2P2,” Acta Materialia 160 224-234 (2018) – [PDF][web]

3. Ian N. Bakst, Hang Yu, Mohammadreza Bahadori, Haibo Yu, Seok-Woo Lee, Mark Aindow, Christopher R. Weinberger*, “Insights into the plasticity of Ag3Sn from Density Functional Theory,” International Journal of Plasticity 110 57-73 (2018) – [PDF][web]

4. Keara Frawley, Ian Bakst, John T. Sypek, Sriram Vijayan, Christopher R. Weinberger, Paul C. Canfield, Mark Aindow, Seok-Woo Lee, “A nanoindentation study on plastic deformation and fracture behaviors of [0 0 1] CaFe2As2 intermetallic compound,” JOM 70, 1074-1080 (2018) [PDF][web]

5. John T. Sypek, Hang Yu, Keith J. Dusoe, Gil Drachuck, Hetal Petal, Amanda M. Giroux, Alan I. Goldman, Andreas Kreyssig, Paul C. Canfield, Sergey L. Bud’ko, Christopher R. Weinberger, Seok-Woo Lee, “Superelasticity and cryogenic linear shape memory effects of CaFe2As2,” Nature Communications 8 1083 (2017) [PDF][web]

6. John T. Sypek, Christopher R. Weinberger, Sriram Vijayan, Mark Aindow, Paul C. Canfield, Seok-Woo Lee, “Superealstic and micaceous deformation in the intermetallic compound CaFe2As2,” Scripta Materialia 141 10-14 (2017) – [PDF][web]

Seok-Woo received “Teaching excellence” for his MSE3004 (Mechanical Behavior of Materials) in 2019 Spring semester. This is his fifth time to receive teaching excellence at UConn.

Tyler’s Al6061 cold spray work was published at Scripta Materialia!

Tyler J. Flanagan, Benjamin Bedard, Alex Ernst, Avinash M. Dongare, Seok-Woo Lee, Harold D. Brody, Victor K. Champagne Jr, Mark Aindow, “Mechanical properties of supersonic-impacted Al6061 microparticles,” – Scripta Materialia, 171, 52-56 (2019) [PDF] [web].

This work studied the mechanical properties of Al6061 microparticles that undergo supersonic impacts with ~1 km/s impact velocity. The effects of initial microstructures and impact velocities on mechanical properties were investigated. This work includes various in-situ videos of micro-compression/tension tests. Please enjoy two of them below!

 

< Micro-tension test >

 

< Interfacial fracture >

Gyuho’s CaKFe4As4 paper is published at Applied Physics Letters (APL) Materials. Many Congratulations!

Gyuho Song, Vladislav Borisov, William R. Meier, Mingyu Xu, Keith J. Dusoe, John T. Sypek, Roser Valenti, Paul C. Canfield, Seok-Woo Lee*, “Ultrahigh elastically compressible and strain-engineerable intermetallic compounds under uni-axial mechanical loading,” APL Materials, 7, 061104 (2019) [PDF] [web]

This paper reports the possibility of superconductivity shut-down under uniaxial compression at the micrometer scale. I love this paper!