Publications de Abhishek Tewari

New approach to low thermal conductivity of thermal barrier protection with improved mechanical integrity

Paul Bowen, Heinrich Hofmann, Abhishek Tewari

Layered ceramic systems with designed stacks of dense and porous layers were investigated as alternative for thermal barrier protection system (TBPs). This approach gives the possibility to obtain low thermal conductivity with the impact protection of dens ...

Elsevier2016

Grain boundary complexion and transparent polycrystalline alumina from an atomistic simulation perspective

Paul Bowen, Abhishek Tewari

Transparent alumina is often processed with sintering additives such as, Y, La, and Mg, in order to limit its grain growth at high sintering temperatures. Usually, these additives segregate to the grain boundaries due to their larger cationic size than Al ...

Elsevier2016

Toward Knowledge-Based Grain-Boundary Engineering of Transparent Alumina Combining Advanced TEM and Atomistic Modeling

Paul Bowen, Marco Cantoni, Michael Stuer, Cécile Hébert, Abhishek Tewari, Farhang Nabiei

Transition element dopants (e.g., Y, La) are commonly used as sintering aids in polycrystalline alumina ceramics, which segregate to the grain boundaries and control the grain-boundary mobility. However, due to the extremely thin (

Wiley-Blackwell2015

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Paul Bowen, Marco Cantoni, Cécile Hébert, Abhishek Tewari, Farhang Nabiei

Small amounts of anion impurities (e.g. Cl), which are incorporated during the synthesis of ceramic powders, can affect the properties and microstructure of the final sintered ceramic. The effect of anion impurities is a little studied and poorly understoo ...

Elsevier Sci Ltd2014

Atomistic Modeling of Effect of Mg on Oxygen Vacancy Diffusion in alpha-Alumina

Paul Bowen, Ulrich Aschauer, Abhishek Tewari

Oxygen diffusion plays an important role in grain growth and densification during the sintering of alumina ceramics and governs high-temperature processes such as creep. The atomistic mechanism for oxygen diffusion in alumina is, however, still debated; at ...

Wiley-Blackwell2014

Atomistic Modeling of Processing Issues for Transparent Polycrystalline Alumina

Abhishek Tewari

Transparent polycrystalline alumina has many possible promising areas of application from jewelry and the watch industry to wave guides, energy economical lamp envelopes, and optical windows. Ultrahigh density, submicron sized grains and/or oriented micros ...

EPFL2013

Load dependence of oxidative wear in metal/ceramic tribocouples in fretting environment

Abhishek Tewari

For a large number of non-oxideceramic/metal as well as for non-oxide particulate reinforced composite/metal tribocouples,oxidative wear is reported to play a major role in the overall damage and material removal process.The designing of new materials with ...

2012

Atomistic modeling of dopant segregation in alpha-alumina ceramics: Coverage dependent energy of segregation and nominal dopant solubility

Paul Bowen, Ulrich Aschauer, Sandra Caroline Galmarini, Yann Aman, Abhishek Tewari

Microstructural control is a key aspect in producing ceramics with tailored properties and is often achieved by using dopants in a rather empirical fashion. Atomic scale simulations could provide much needed insight but the long-standing challenge of linki ...

2011