Plastic Deformation, Residual Stress, and Crystalline Texture Measurements for In-Process Characterization of FCC Metal Alloys

The need for in-process characterization of metallic components is being recognized increasingly. In the field of x-ray analysis the x-ray fluorescent (spectroscopy) techniques have been successfully applied to in-process inspection, while successes in x-ray diffraction have been sparse. X-ray diffraction characterization techniques should be fast, non-contacting, and tolerant of detector to component distance variation. The Ruud-Barrett position-sensitive scintillation detector (R-B PSSD) is unique in its ability to satisfy these requirements, and has been successful in measuring plastic deformation, residual stress and crystalline texture in FCC metal alloys

The Representation of Texture in Cold-Rolled Copper Sheet by an Advanced X-Ray Diffraction Technique

The influence of texture on forming properties of metals has widely been recognized [l–4]. Preferred orientation of the crystallites (grains) in polycrystalline aggregates results in anisotropy of the mechanical properties. The desired degree of, or absence of, anisotropy depends on the particular process of forming, and any subsequent manufacturing process requires certain material properties for satisfactory performance. For example, the type of texture desired in deep drawing is quite different from the one necessary for simple stamping or multiaxial bending. Thus, in-process texture monitoring is receiving increased interest, both from manufacturers and researchers [4,5].</p

Microphase separation of highly amphiphilic, low N polymers by photoinduced copper-mediated polymerization, achieving sub-2 nm domains at half-pitch

The lower limit of domain size resolution using microphase separation of short poly(acrylic acid) homopolymers equipped with a short fluorinated tail, posing as an antagonist 'A block' in pseudo AB block copolymers has been investigated. An alkyl halide initiator with a fluorocarbon chain was utilized as a first 'A block' in the synthesis of low molecular weight polymers (1400-4300 g mol -1) using photoinduced Cu(ii)-mediated polymerization allowing for very narrow dispersity. Poly(tert-butyl acrylate) was synthesized and subsequently deprotected to give very low degrees of polymerization (N), amphiphilic polymers with low dispersity (D = 1.06-1.13). By exploiting the high driving force for demixing and the well-defined 'block' sizes, we are able to control the nanostructure in terms of domain size (down to 3.4 nm full-pitch) and morphology. This work demonstrates the simple and highly controlled synthesis of polymers to push the boundaries of the smallest achievable domain sizes obtained from polymer self-assembly