Search results for "Mechanics of Material"

Area‐Selective Atomic Layer Deposition on Functionalized Graphene Prepared by Reversible Laser Oxidation

2022

Publisher Copyright: © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH. Area-selective atomic layer deposition (ALD) is a promising “bottom-up” alternative to current nanopatterning techniques. While it has been successfully implemented in traditional microelectronic processes, selective nucleation of ALD on 2D materials has so far remained an unsolved challenge. In this article, a precise control of the selective deposition of ZnO on graphene at low temperatures (<250 °C) is demonstrated. Maskless femtosecond laser writing is used to locally activate predefined surface areas (down to 300 nm) by functionalizing graphene to achieve excellent ALD selectivity (up to…

Argon bubble flow in liquid gallium in external magnetic field

2020

Photoconductivity in the columnar phases of a glassy discotic twin

1995

Energy Barrier: Focus on the Essential: Extracting the Decisive Energy Barrier of a Complex Process (Adv. Mater. Interfaces 20/2019)

2019

New Twists of 3D Chiral Metamaterials

2018

Rationally designed artificial materials, called metamaterials, allow for tailoring effective material properties beyond ("meta") the properties of their bulk ingredient materials. This statement is especially true for chiral metamaterials, as unlocking certain degrees of freedom necessarily requires broken centrosymmetry. While the field of chiral electromagnetic/optical metamaterials has become rather mature, the field of elastic/mechanical metamaterials is just emerging and wide open. This research news reviews recent theoretical and experimental progress concerning 3D chiral mechanical and optical metamaterials, with special emphasis on work performed at KIT.

Structural properties of the quaternary Heusler compound Co2 Cr1−x Fex Al

2006

Abstract The structural and chemical properties of the quaternary Heusler compound Co2 Cr1−x Fex Al were investigated comparing powder and bulk samples. The long range order was determined by means of X-ray diffraction, while the site specific (short range) order was proved by the extended X-ray absorption fine structure method (EXAFS). The chemical composition was analysed by means of X-ray photo emission spectroscopy (XPS) combined with Auger electron spectroscopy (AES) depth profiling. The results from these methods are compared to get a detailed idea about the differences between surface and bulk properties and appearance of disorder in such alloys.

Fabrication of layered nanostructures by successive electron beam induced deposition with two precursors: protective capping of metallic iron structu…

2011

We report on the stepwise generation of layered nanostructures via electron beam induced deposition (EBID) using organometallic precursor molecules in ultra-high vacuum (UHV). In a first step a metallic iron line structure was produced using iron pentacarbonyl; in a second step this nanostructure was then locally capped with a 2-3 nm thin titanium oxide-containing film fabricated from titanium tetraisopropoxide. The chemical composition of the deposited layers was analyzed by spatially resolved Auger electron spectroscopy. With spatially resolved x-ray absorption spectroscopy at the Fe L₃ edge, it was demonstrated that the thin capping layer prevents the iron structure from oxidation upon e…

An integrated approach to evaluating the tribo-contact for coated cutting inserts

2000

Abstract The orthogonal machining process when end turning medium carbon and austenitic stainless steels with cemented WC-Co tools coated with single-layer (TiC), two-layer (TiC/TiN), and three-layer (TiC/Al2O3/TiN) hard thin films was investigated. Extensive experimental investigations including the thermal, mechanical and tribological responses of the tribo-contact between the coating–substrate system and the chip, under different cutting conditions, were carried out. The study sheds light on the cutting forces, the interface temperatures and the tribo-contact conditions, including the friction energy dissipated at the tool–chip interface, the frictional heat flux conducting into either t…

Effect of Plastic hot deformation on the hardness and continuous cooling transformations of 22MnB5 micro-alloyed boron steel

2009

The strains, transformation temperatures, microstructure, and microhardness of a microalloyed boron and aluminum precoated steel, which has been isothermally deformed under uniaxial tensile tests, have been investigated at temperatures between 873 and 1223 K, using a fixed strain rate value of 0.08 s−1. The effect of each factor, such as temperature and strain value, has been later valued considering the shift generated on the continuous cooling transformation (CCT) diagram. The experimental results consist of the starting temperatures that occur for each transformation, the microhardness values, and the obtained microstructure at the end of each thermomechanical treatment. All the thermome…

Localized hydrogen cracking in the austenitic phase of a duplex stainless steel

1996

The aim of this study is to investigate the role of hydrogen on the mechanical behavior of an austenitic phase, in the particular situation of duplex stainless steels. In these duplex alloys, in presence of hydrogen, the ferritic phase is embrittled by hydrogen and the resistance to cracking is mainly related to the behavior of the austenitic phase. Thus, a discussion of the role of hydrogen at the crack tip of a duplex alloy (as function of the microstructure) has been proposed by T. Perng and C.J. Altester after experiments conducted in gaseous environment. A similar experimental approach has been followed in this study; slow strain rate tests (SSRT) have been performed on duplex stainles…