Effects of Short-Term Annealing on the Thermal Stability and Microstructural Evolution of Oxygen-Free Copper Processed by High-Pressure Torsion.

This study explores the impact of short-term annealing on the thermal stability and mechanical properties of oxygen-free copper subjected to high-pressure torsion (HPT). Copper samples were deformed through HPT with varying numbers of turns at room temperature and subsequently subjected to short-term annealing at temperatures of 398 K and 423 K. Microstructural analysis revealed that annealing led to grain growth and a reduction in dislocation density, with samples processed with fewer HPT turns exhibiting more significant grain coarsening.

The Microstructure Formation of a Protective Oxide-Scale Layer on Small-Diameter FeCrAl Fibers.

FeCrAl fibers, at high temperatures, form a protective oxide-scale layer dominated by aluminum oxide on the surface to prevent further oxidation of the base metal alloy. This study investigates the effects of heat treatment on the microstructure formation of the oxide-scale layer on small-diameter FeCrAl fibers, 12 and 17 µm, produced using a bundle drawing process. The morphology examination and chemical analyses of the small-diameter fibers exhibit the microstructure and chemical compositions of the surface and cross-section areas, revealing a distinctive interface layer with a high aluminum concentration between the base metal and the oxide-scale layer.

Multistage heat treatment and the development of a protective oxide-scale layer on the surface of FeCrAl sintered-metal-fibers.

This study investigates the effects of Multistage Heat Treatment (MSHT) on the development of an oxide-scale layer on the surface of FeCrAl sintered-metal-fibers. The oxide-scale layer was developed using an MSHT cycle at 930 °C for 1 h, followed by 960 °C for 1 h, and finally at 990 °C for 2 h. In this study, three samples were considered: Sample 1 was kept without thermal oxidation, while Samples 2 and 3 were exposed to one and eighteen MSHT cycles.

Surface Evaluation of a Multi-Pass Flexible Magnetic Burnishing Brush for Rough and Soft Ground 60/40 Brass.

Burnishing is an advanced finishing process that produces higher-quality surfaces with better hardness and roughness than conventional finishing processes. Herein, a flexible magnetic burnishing brush comprising stainless steel pins under permanent magnet poles was used to investigate the influence of multiple passes and directions on the produced surface of soft and rough ground prepared brass. In total, five different samples were burnished on each of the two brass samples prepared.

Ultrasmooth submicrometer carbon spheres as lubricant additives for friction and wear reduction.

Ultrasmooth submicrometer carbon spheres are demonstrated as an efficient additive for improving the tribological performance of lubricating oils. Carbon spheres with ultrasmooth surfaces are fabricated by ultrasound assisted polymerization of resorcinol and formaldehyde followed by controlled heat treatment. The tribological behavior of the new lubricant mixture is investigated in the boundary and mixed lubrication regimes using a pin-on-disk apparatus and cylinder-on-disk tribometer, respectively.