Bauschinger effect in unpassivated freestanding thin films

Two-dimensional (2D) discrete dislocation plasticity simulations are carried out to investigate the Bauschinger effect (BE) in freestanding thin films. The BE in plastic flow of polycrystalline materials is generally understood to be caused by inhomogeneous deformation during loading, leading to residual stress upon unloading. This inhomogeneity...

Stress in tungsten carbide-diamond like carbon multilayer coatings

Tungsten carbide-diamond like carbon (WC-DLC) multilayer coatings have been prepared by sputter deposition from a tungsten-carbide target and periodic switching on and off of the reactive acetylene gas flow. The stress in the resulting WC-DLC multilayers has been studied by substrate curvature. Periodicity and microstructure have been studied by...

Enhancing the charge ordering temperature in thin films of Pr0.5Ca0.5MnO3 by strain

We report the effects of biaxial strain on the charge ordering temperature Tco of the mixed-valent manganite perovskite oxide Pr0.5Ca0.5MnO3. Thin films were grown on SrTiO3, which has a 1.3% larger in-plane lattice parameter. Other substrates were used for comparison. Transport measurements combined with data from electron microscopy show that...

Evaluation of an Empirical Model to Estimate and Optimize Mechanical Properties of PECVD SiC Films

In this paper, we present a systematic investigation of the influence of the deposition parameters on the deposition rate, etch rate, and mechanical stress of SiC films prepared by plasma-enhanced chemical vapor deposition (PECVD) technique. Among the relevant deposition parameters, the SiH4 gas flow rate, the main parameter to determine the Si...

Stress in sputter-deposited Cr films: Influence of Ar pressure

We studied the tensile stress and grain-width evolution in sputter-deposited Cr films with thickness from 20?nm to 2.7??m. Films were deposited in an industrial Hauzer 750 physical vapor deposition machine at 50–80?°C. The films exhibited a columnar microstructure. A power law behavior of the tensile stress as well as of the average grain width...

Stress in hard metal films

In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion bombardment. In polycrystalline hard metal films the grain...

A direct-numerical-simulation-based second-moment closure for turbulent magnetohydrodynamic flows

A magnetic field, imposed on turbulent flow of an electrically conductive fluid, is known to cause preferential damping of the velocity and its fluctuations in the direction of Lorentz force, thus leading to an increase in stress anisotropy. Based on direct numerical simulations (DNS), we have developed a model of magnetohydrodynamic (MHD)...

Tensile stress in hard metal films

Thin films on substrates are usually in a stressed state. An important, but trivial, contribution to that stress stems from the difference in thermal expansion coefficient of substrate and film. Much more interesting are the intrinsic stresses, resulting from the growth and/or microstructure of the film. Intrinsic compressive stress was...