Microdiffraction System Research Articles

Development of compound refractive lenses made of quartz glass designed for microdiffraction system at BL13XU in SPring-8

We developed compound refractive lenses made of quartz glass for wide range of X-ray energy and investigated the focusing performance. The lenses for X-ray energy of 10, 12.4, 15, 20, 25, 30 keV were fabricated by optical lithography and dry etching techniques. Two lenses with the focal distance of 100 and 200 mm were combined in a crossed geometry to achieve two dimensional focusing. The measurements of the focusing properties were performed at beamline BL13XU in SPring-8 with a high-resolution microdiffraction system. The microbeams with the beam size less than 3.2 μm in both vertical and horizontal direction were obtained at all the energies. We also investigated the influence of the local lens condition to the focusing ability. It is found that the focal position moved depending on the illuminated position on the lens due to the shape errors, which causes the increase of the total beam size.

Local stress gradients in Ti/Al composite wires determined by two-dimensional X-ray microdiffraction

By means of a two-dimensional X-ray microdiffraction system, the stress state of a severely deformed ultrafine-grained Ti/Al composite wire was investigated in terms of the local stress development with the increasing degree of deformation. The wire was processed by Accumulative Swaging and Bundling in order to gain a high-strength composite material, potentially suitable for light-weight applications. In the present paper, the non-conventional measurement system based on the two-dimensional X-ray diffraction and its application is elucidated. Particularly, the results of the local residual stress development concerning different degrees of deformation are shown and discussed with respect to (i) the development of texture, microstructural and mechanical properties of the severely deformed ultrafine-grained material composite as well as (ii) the intrinsic characteristics of the Accumulative Swaging and Bundling process.

Texture development in Ti/Al filament wires produced by accumulative swaging and bundling

Mechanical properties of ultra-fine grained materials are interesting for advanced engineering applications. For producing ultra-fine grained microstructures, various top-down processes of severe plastic deformation like equal channel angular pressing, high pressure torsion and accumulative roll bonding are available. The evolution of texture with respect to deformation by an alternative severe plastic deformation process, called accumulative swaging and bundling, is shown for ultra-fine grained Ti/Al composite wires, suitable for structural applications because of their high specific strength. In this cyclic process, an aluminium rod is inserted into a titanium tube before being swaged with an areal reduction of 20% per pass to a true strain of 4.3. After cleaning and cutting the resulting composite wire into 37 pieces, these are stacked in hexagonal arrangement into another Ti tube of the initial dimension before deformation is continued.The local texture gradient of the accumulative swaging and bundling composites was studied using a X-ray microdiffraction system based on a D8 Discover (Bruker AXS GmbH) equipped with a microfocus X-ray tube Iμ S and an area detector VÅNTEC-2000. The results are discussed with respect to the grain refining deformation process starting from the initial texture measured by synchrotron and neutron diffraction, respectively.The local Al and Ti texture evolution is related to the deformation mode, which is similar to extrusion. As such, an Al〈111〉+〈100〉-double fibre and a Ti〈101¯0〉-fibre emerge as the main texture components, each revealing gradients related to the deformation process. In particular, the local Al texture – being a function of both radial measurement position and deformation stage – can be correlated to material and process related issues like plastic flow and the superposition effect due to encapsulated filaments, respectively.

Nanometer-Scale Characterization Technique for Si Nanoelectric Materials Using Synchrotron Radiation Microdiffraction

We have developed new microdiffraction system at the SPring-8. This system uses a focused beam produced using a phase zone plate combined with a narrow slit, which makes a small focused beam that has a small angular divergence. Furthermore, we can use the two-dimensional x-ray CCD detector, which enable us to measure local reciprocal space maps at many points in a sample, that is, the distribution of strain fields and lattice tilts can be revealed in high-angular- and high-spatial-resolution.

Size-Frustrated Thickening Growth of Extended-Chain Crystals in a Poly (Ethylene Terephthalate)/Bisphenol A Polycarbonate Blend Under High Pressure

High-pressure crystallized blend samples of poly (ethylene terephthalate)/bisphenol A polycarbonate (PET/BAPC) were investigated with scanning electron microscopy (SEM), confocal laser micro-Raman spectroscopy, and a standard general area detector diffraction system (GADDS) X-ray micro-diffraction system. The results showed that long time annealing at high pressure could result in extended-chain polymer single crystals with thicker lamellae. However, the large size of such crystals was also found to frustrate their thickening growth along the c-axis thickness, as demonstrated by the observation of a novel wrinkled crystal. The winkled crystals with different morphologies were thought to be formed as the compromise between the kinetic pathway and the thermodynamic driving force during the size-frustrated thickening growth of the large polymer crystals. Further observations revealed that environmental confinement was the main factor responsible for the creation of the wrinkled structures in polymer extended-chain crystals. The present study may promote understanding of the fundamental nature of the crystal thickening in these binary polyester blends.

An alternative micro-area X-ray diffraction method for residual stress measurement of Pb(Zr,Ti)O 3 film

An alternative X-ray diffraction method for micro-area residual stress measurement was proposed by means of the analysis of a single diffraction ring, which was performed on a laboratory X-ray microdiffraction system equipped with a 2D planar detector. The microdiffraction experiments were employed to evaluate the residual stress in sol–gel-derived Pb(Zr,Ti)O 3 film before and after Ag electrode deposition. The tensile stresses of about 2.3 GPa and 1.2 GPa were calculated in the micro-area of film without and with electrode, which was related to a top electrode stress relaxation effect.

Grain Orientation Mapping and Spatially Resolved Strain Measurements for Polycrystalline Films by X-Ray Microdiffraction

AbstractWe describe spatially resolved grain orientation mapping of polycrystalline films using a synchrotron-based x-ray microdiffraction system. The system consists of a tapered glass capillary as a white x-ray concentrator, an energy-dispersive solid state detector and an x-y-z sample stage. Two mapping modes are discussed: reciprocal-space mapping and real-space mapping. Information about the orientations of grains within the irradiated volume is determined by reciprocal-space mapping. The locations of grains having a specified orientation are determined by real-space mapping. Examples are shown for blanket films of AI(4 wt.% Cu) 4μm-thick and 0.5μm thick. Results are also shown for 10μm-wide and μm-wide pure lines. X-ray beams of 10inm diameter were used for these measurements. Spatially resolved thermal strain measurements were made for a single 10μm-wide, 200μm-long passivated Al line, and they were found to be consistent with calculations based on equi-biaxial thermal stress within the line.