Papers by Keyword: Fiber Texture

Abstract: X-ray diffraction stress analysis by crystallite group method (CGM) has been employed in case of simultaneously strong and sharp fiber textured Ti thin films. These Ti films exhibit thickness dependent hcp-fcc phase transformation [Ref. 1]. Diffraction stress analysis has also been attempted by d-sin2 method for strongly textured face centered cubic (fcc) and hexagonal close packed (hcp) Ti phases. For hcp Ti phase, the results of stress analysis by CGM are compared with those obtained from d-sin2 method. It is found that the stress values in hcp Ti phases obtained from CGM considerably differ from the stresses obtained from d-sin2 method in some of the Ti films. Observed differences have been explained and possible sources of errors in d-sin2 method and CGM stress analysis have been discussed.

Abstract: In present research, the structure evolution of the pearlite steel wire during cold drawing is systematically investigated, and the relationship between structure evolution and strength increase during wire drawing is analyzed. During cold drawing, the wire strength increases; inter-lamellar spaces of the pearlites decrease, which has an important effect on properties of cold drawn wires; accumulation of high density dislocation in ferrite phase can be thought to be one of the reasons for strengthening the wire, meanwhile, the amorphous phase forming in cemetites also make the wire strengthen; especially, the wire strength is effected seriously by the intensity of the fiber texture <110>, and as drawing, the wire strength increases.

Abstract: Microstructure and texture formation behavior of a gold rod and fine wire which were produced by continuous casting process and drawing, respectively were investigated by means of optical micrographs, TEM images and X-ray pole figure. Well-developed unidirectional structure aligned to casting direction was found in 7 mm gold rod. Higher casting speed was found to be favor in developing the directional microstructure. In the sample with unidirectional microstructure developed in partial it is found that dislocation substructure with nano-size appeared to display a characteristic feature, while no dislocation substructure is seen in the sample with complete unidirectional microstructure. Interface stability between solid and liquid may be responsible for this difference in dislocation substructure. <100> fiber component was observed to be well developed over the whole microstructure in unidirectional sample. With decreasing casting speed <100> fiber component became weak. Two texture components consisting of <111> fiber and <100> fiber were seen in as-drawn samples. For the development of <111> fiber texture component initial texture component plays a more significant role than subsequent annealing process. Annealing heat treatment would be effective way to control the formation of <100> fiber component. On the basis of results obtained it is suggested that both the initial texture and final annealing are important in controlling the texture of gold bonding wire.

Abstract: In this study, we have investigated a texture and microstructure of gold bonding wire by transmission electron microscope, X-ray diffraction and electron back scatter diffraction according to process parameters, such as casting, drawing and annealing processes. The gold was cast into 7mm diameter rods by vertical continuous casting technique, the cast rods were drawn to a final wire size of 25μm, and then the fine wires were annealed. A unidirectional solidification structure having <100> fiber texture of cast rod was strongly developed depending on casting route and speed. In the sample with unidirectional microstructure developed in partial it is found that dislocation substructure with nano-size appeared to display a characteristic feature, while no dislocation substructure is seen in the sample with complete unidirectional microstructure. Interface stability between solid and liquid may be responsible for this difference in dislocation substructure. With decreasing casting speed <100> fiber component became weak. Initial texture plays important role on development of <111> fiber texture at drawing and final annealing stages. On the basis of results obtained it is suggested that both the initial texture are important in controlling the texture of gold bonding wire.

Abstract: Industrially processed doped-tungsten wires in the as-drawn condition have essentially a <110>-fibre texture with attractive mechanical properties. The main objectives of the present work are to investigate (I) if any textural changes occur as the wire diameter decreases and (II) if such changes influence the mechanical behaviour of the wire. A wire of about ∅1.5mm is drawn to about ∅0.15mm following a standard industrial route and samples were collected from five intermediate drawing passes. Bulk texture measurements using X-radiations were then carried on the transverse sections of the wires and texture characteristics such as volume fraction of textural components and sharpness index were quantified with respect to the wire diameter. It was observed that the texture in the as-drawn wires remains chiefly the same <110>-fibre as the wire diameter decreases. However, the sharpness of texture reaches a maximum at a certain diameter and decreases with further decrease in the wire diameter. An explanation is offered based on the concept of deformation zone geometry. An attempt was also made to determine if texture weakening has any effect on the mechanical properties of the wire at room temperature.

Abstract: In this study a detailed analysis is given of the development of preferred orientations of polycrystalline diamond films, deposited from the gas phase using the combustion-flame assisted chemical vapor deposition technique, as a function of the amount of intentionally added nitrogen. The preferred orientations are studied using X-ray diffraction and are compared with the morphological changes of the sample surfaces. The role of nitrogen in the deposition process is discussed. Low amounts of nitrogen enhance the growth rate and lead from a randomly oriented layer successively to {011} and {001} fiber textures. Higher amounts of nitrogen deteriorate the growth; no preferred orientation is visible anymore.

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.