Papers by Keyword: Grazing Incidence X-Ray Diffraction

Abstract: The nanostructure of α phase polyoctylfluorene thin film was characterized using normal X-ray diffraction, one-dimensional out-of-plane grazing incidence X-ray diffraction and two-dimensional grazing incidence X-ray diffraction with lab diffractometer and synchrotron diffractometer. The results show that using grazing incidence X-ray diffraction the weak diffraction signal of thin film can be observed after the elimination of background signals. Incorrect (h10) diffraction signals can be collected by lab diffractometer due to its low collimation and resolution, which can be overcome by using synchrotron diffractometer with high collimation and resolution that reveal the actual microstructure of polyoctylfluorene thin film.

Abstract: Laser shock processing (LSP) is a new and competitive technology in comparison with classical mechanical surface treatments for alloys strengthening. The compressive residual stress could be induced by LSP, which further significantly affects materials surface properties. Aluminum based alloy 6056 is used for aeronautic components and their surface strengthening is very important to increase components’ durability. The main factors of LSP, which affect the surface properties of alloys, such as surface roughness and residual stress gradient, are studied and analyzed in present study. The sin2* method with pseudo-grazing incidence X-ray diffraction (GIXRD) is used to determine the residual stress gradient after LSP treatment. In addition, the FEM simulation of residual stress distribution induced by LSP is also carried out and the results are compared with experimental data.

Abstract: The effects of nitrogen pre-implantation of AISI C1045 steel substrates on the properties of deposited TiN coatings were investigated. Nitrogen ion implantations were performed at 40 keV, to the fluences from 5x1016 – 5x1017 ions/cm2. On so prepared substrates we deposited 1.3 μm thick TiN layers by reactive sputtering. Structural characterizations of the samples were performed by grazing incidence X-ray diffraction analysis (GXRD), standard X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM). Microhardness was measured by Vicker’s method. The obtained results indicate the formation of iron-nitrides in the near surface region of the substrates, more pronounced for higher implanted fluences. The structure of the deposited TiN coatings shows a strong dependence on the pre-implantation of the substrates, which is attributed to the changed local structure at the surface. Ion implantation and deposition of hard TiN coatings induce an increase of the microhardness of this low performance steel of more than eight times.

Abstract: The TiN films with the thickness of 0.1, 0.2, 0.5, 1.0, and 4.0 µm were coated on a steel substrate by the ion beam mixing method. The film had a strong fiber texture with <001> axis perpendicular to the film surface. The in-plane stress measurement was applicable to the thickness down to 0.1 µm of TiN films. The stress was a compression of around 2 GPa. The compressive stress was found to increase below the surface layer of 20 to 30 nm. Thinner films had a steeper increase of the compressive stress in the very-near surface region. The strain distribution measured by the SV method was nearly constant over the region of the penetration depth between 0.3 and 0.6 µm from the surface. The two-tilt method combined with the surface removal method showed a nearly constant distribution of compression in the subsurface region and a sharp increase near the interface to the substrate.