Search Results - "Hemker, Kevin J."

Mechanisms of deformation and ductility in tungsten – A review by Butler, Brady G., Paramore, James D., Ligda, Jonathan P., Ren, Chai, Fang, Z. Zak, Middlemas, Scott C., Hemker, Kevin J.

“…The physical, chemical, and mechanical properties of tungsten are at the far limits of all engineering materials. These unique properties, particularly…”
Get full text

Low-Overpotential Electroreduction of Carbon Monoxide Using Copper Nanowires by Raciti, David, Cao, Liang, Livi, Kenneth J. T, Rottmann, Paul F, Tang, Xin, Li, Chenyang, Hicks, Zachary, Bowen, Kit H, Hemker, Kevin J, Mueller, Tim, Wang, Chao

“…We report on Cu nanowires as highly active and selective catalysts for electroreduction of CO at low overpotentials. The Cu nanowires were synthesized by…”
Get full text

Mechanistic Insights for Low-Overpotential Electroreduction of CO2 to CO on Copper Nanowires by Cao, Liang, Raciti, David, Li, Chenyang, Livi, Kenneth J. T, Rottmann, Paul F, Hemker, Kevin J, Mueller, Tim, Wang, Chao

“…Recent developments of copper (Cu)-based nanomaterials have enabled the electroreduction of CO2 at low overpotentials. The mechanism of low-overpotential CO2…”
Get full text

In situ TEM observations of fast grain-boundary motion in stressed nanocrystalline aluminum films by Legros, Marc, Gianola, Daniel S., Hemker, Kevin J.

“…Free-standing nanocrystalline Al thin films have been strained in situ in a transmission electron microscope at room-temperature. Extensive grain-boundary…”
Get full text

New Ground-State Crystal Structure of Elemental Boron by An, Qi, Reddy, K Madhav, Xie, Kelvin Y, Hemker, Kevin J, Goddard, William A

“…Elemental boron exhibits many polymorphs in nature based mostly on an icosahedral shell motif, involving stabilization of 13 strong multicenter…”
Get full text

Characterizing deformed ultrafine-grained and nanocrystalline materials using transmission Kikuchi diffraction in a scanning electron microscope by Trimby, Patrick W., Cao, Yang, Chen, Zibin, Han, Shuang, Hemker, Kevin J., Lian, Jianshe, Liao, Xiaozhou, Rottmann, Paul, Samudrala, Saritha, Sun, Jingli, Wang, Jing Tao, Wheeler, John, Cairney, Julie M.

“…The recent development of transmission Kikuchi diffraction (TKD) in a scanning electron microscope enables fast, automated orientation mapping of electron…”
Get full text

Nucleation of amorphous shear bands at nanotwins in boron suboxide by An, Qi, Reddy, K. Madhav, Qian, Jin, Hemker, Kevin J., Chen, Ming-Wei, Goddard III, William A.

“…The roles of grain boundaries and twin boundaries in mechanical properties are well understood for metals and alloys. However, for covalent solids, their roles…”
Get full text

Deformation Twinning in Nanocrystalline Aluminum by Chen, Mingwei, Ma, En, Hemker, Kevin J., Sheng, Hongwei, Wang, Yinmin, Cheng, Xuemei

“…We report transmission electron microscope observations that provide evidence of deformation twinning in plastically deformed nanocrystalline aluminum. The…”
Get full text

Shock-Induced Localized Amorphization in Boron Carbide by Chen, Mingwei, McCauley, James W., Hemker, Kevin J.

“…High-resolution electron microscope observations of shock-loaded boron carbide have revealed the formation of nanoscale intragranular amorphous bands that…”
Get full text

Effect of Alumina on the Structure and Mechanical Properties of Spark Plasma Sintered Boron Carbide by Xie, Kelvin Y., Toksoy, Muhammet F., Kuwelkar, Kanak, Zhang, Binwei, Krogstad, Jessica A., Haber, Richard A., Hemker, Kevin J.

“…Uniform densification of relatively thick (~7 mm) consolidated boron carbide plates at relatively low temperatures (e.g. 1800°C) and low facture toughness are…”
Get full text

Bending Nanoindentation and Plasticity Noise in FCC Single and Polycrystals by Bolin, Ryder, Yavas, Hakan, Song, Hengxu, Hemker, Kevin J., Papanikolaou, Stefanos

“…We present a high-throughput nanoindentation study of in situ bending effects on incipient plastic deformation behavior of polycrystalline and…”
Get full text

Effect of strain rate and dislocation density on the twinning behavior in tantalum by Florando, Jeffrey N., El-Dasher, Bassem S., Chen, Changqiang, Swift, Damian C., Barton, Nathan R., McNaney, James M., Ramesh, K. T., Hemker, Kevin J., Kumar, Mukul

“…The conditions which affect twinning in tantalum have been investigated across a range of strain rates and initial dislocation densities. Tantalum samples were…”
Get full text

Microstructural evolution of pure magnesium under high strain rate loading by Dixit, Neha, Xie, Kelvin Y., Hemker, Kevin J., Ramesh, K.T.

“…The mechanical behavior of extruded pure magnesium was studied experimentally under high strain rate ) compression loading in the extrusion direction. Electron…”
Get full text

In Situ Measurement of the Toughness of the Interface Between a Thermal Barrier Coating and a Ni Alloy by Eberl, Christoph, Wang, Xi, Gianola, Daniel S., Nguyen, Thao D., He, Ming Y., Evans, Anthony G., Hemker, Kevin J.

“…A flexural test for the in situ measurement of the delamination toughness of the interface between a thermally grown oxide and a bond coat in the presence of a…”
Get full text

Experimental quantification of mechanically induced boundary migration in nanocrystalline copper films by Rottmann, Paul F., Hemker, Kevin J.

“…A new experimental technique is presented that combines in situ straining with transmission electron microscope-based automated crystal orientation mapping to…”
Get full text

TMS: A Link to Our Past; A Bridge to Our Future by Hemker, Kevin J

“…The author, like many, view TMS as his home society and going to the TMS annual meeting as a kind of professional family reunion, where we share a materials…”
Get full text

Microstructural characterization of boron-rich boron carbide by Xie, Kelvin Y., Domnich, Vladislav, Farbaniec, Lukasz, Chen, Bin, Kuwelkar, Kanak, Ma, Luoning, McCauley, James W., Haber, Richard A., Ramesh, K.T., Chen, Mingwei, Hemker, Kevin J.

“…Boron carbide has a wide range of solubility, but the effects of stoichiometry on its microstructure and mechanical response are not well understood. In this…”
Get full text

Effect of stress-relief heat treatments on the microstructure and mechanical response of additively manufactured IN625 thin-walled elements by Banerjee, Arunima, He, Mo-Rigen, Musinski, William D., Shade, Paul A., Cox, Marie E., Schwalbach, Edwin J., Hemker, Kevin J.

“…Metallic structures fabricated with laser powder-bed fusion (LPBF) often have elemental segregations that are far from equilibrium and high levels of residual…”
Get full text

A statistical model for predicting size effects on the yield strength in dislocation-mediated crystal plasticity by Gu, Yejun, Eastman, David W., Hemker, Kevin J., El-Awady, Jaafar A.

“…A unified statistical dislocation-mediated crystal plasticity model is proposed to understand how the sample size affects the yield strength of metals in…”
Get full text

Tailoring the coefficient of thermal expansion of ternary nickel alloys through compositional control and non-contact measurements by Valentino, Gianna M., Krogstad, Jessica A., Weihs, Timothy P., Hemker, Kevin J.

“…The majority of microelectromechanical systems (MEMS) are made of silicon, however, future applications will be used in extreme environments, especially at…”
Get full text