X-ray Investigation of Microstructure and Properties Evolution on Superalloy Inconel-718 derivative during Rapid Joule Heating and Severe Plastic Deformation Concurrently

The purpose of this study is to X-ray line-profile analysis of the effect of rapid Joule heating and severe plastic deformation concurrently on microstructure and properties evolution in polycrystalline austenitic Fe-balanced superalloy EP718E, which is Inconel 718 derivative. The microstructure of superalloy at different stages of processing was examined by X-ray diffraction, by scanning electron microscopy, and by energy dispersive spectrometry techniques. The mechanical properties of evolution were studied by means of tension and high cycle fatigue testings. The results of X-ray study show that the intensity, raw areas, and net areas were a step–by–step changed according to processing routines. Is shown that under shear stress the fcc-crystallites were deformed and the peaks parameters by 2-Theta scale changed partly

Wear behavior of ceramic-metal composites as tool materials for FSW of stainless steel

Friction stir welding (FSW) is a solid-state joining process that uses a non-consumable tool to join materials by mixing them mechanically in the weld area instead of melting the materials. The temperatures of the high-quality FSW process for stainless steels are above 1000˚C. The main wear mechanism for a FSW tool in the case of stainless steels is diffusion controlled wear. In our study, wear and diffusion tests were performed at the temperature close to the welding process for better physical simulation of real-life FSW tool wear conditions by turning stainless steel AISI304 at high speed. Tool materials such as WC–Co cemented carbides and TiC–based cermets with different binder composition and fraction were used. The temperature required in the cutting zone was achieved by increasing the cutting speed. To measure the temperature at the interface of the cutting tool and the workpiece, the method based on the thermoelectric effect was used. The wear was determined as the change of the geometry of the cutting edges of the tool. Microscopic investigations were performed using scanning electron microscopy. The diffusion mechanism was studied using the energy dispersive X–ray spectroscopy (EDS). TiC–based cermets with nickel based binder TiC–NiMo demonstrated superiority over WC–Co cemented carbides and TiC–based Fe–alloys bonded cermets TiC–FeNi and TiC–FeCr

Sensitivity of ZnO films doped with Er, Ta and Co to NH3 at room temperature

International audienceThe sensitivity of ZnO films, undoped and doped with Er, Ta and Co, to exposure to NH3 has been studied. The films were deposited by magnetron co-sputtering of a sintered ZnO target with chips of the different doping elements on its surface. The sensitivities of the ZnO films to exposure to NH3 were measured by the quartz crystal microbalance method using the resonance frequency shift. The adsorption process was investigated over an aqueous solution of ammonia with 100 ppm concentration. The speed and the mass of sorption were calculated on the basis of the time-frequency characteristic. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Investigation of the ripple pattern formation on nanocrystalline diamond film surfaces during reciprocating sliding against Si₃N₄ balls

status: publishe