Indentation-induced localized deformation and elastic strain partitioning in composites at submicron length scale

Three-dimensional spatially resolved strains were mapped in a model NiAl/Mo composite after nanoindentation. The depth-dependent strain distributed in the two phases and partitioned across the composite interfaces is directly measured at submicron length scale using X-ray microdiffraction and compared with a detailed micromechanical stress analysis. It is shown that indentation-induced deformation in the composite material is distinct from deformation expected in a single-phase material. This difference arises in part from residual thermal strains in both phases of the composite in the as-grown state. Interplay between residual thermal strains and external mechanical strain results in a complex distribution of dilatational strain in the Mo fibers and NiAl matrix and is distinct in different locations within the indented area. Reversal of the strain sign (e.g., alternating tensile/compressive/tensile strain distribution) is observed in the NiAl matrix. Bending of the Mo fibers during indentation creates relatively large ～1.5° misorientations between the different fibers and NiAl matrix. Compressive strain along the 〈0 0 1〉 direction reached ?0.017 in the Mo fibers and ?0.007 in the NiAl matrix.     

Characterization and modeling of heterogeneous deformation in commercial purity titanium

Heterogeneous deformation, including local dislocation shear activity and lattice rotation, was analyzed in microstructure patches of polycrystalline commercial purity titanium specimens using three different experimental methods. The measurements were compared with crystal plasticity finite element simulations for the same region that incorporate a local phenomenological hardening constitutive model. The dislocation activity was measured using techniques associated with atomic force microscopy, confocal microscopy, three-dimensional x-ray diffraction, and nano-indentation. The results indicate that a major challenge for model development is to effectively predict conditions where slip transfer occurs, and where geometrically necessary dislocations accumulate.     

Flotation clean-up of waste water from high-modulus viscose fibre manufacturing from surface-active substances

Conclusions The possibility of cleaning up wastewater from nonionic surface-active substances (NSAS) by the flotation method (foam separation) has been demonstrated under experimental conditions.It has been found that the main factor which affects the degree of extraction of NSAS from wastewater is the ratio between the berol-visko 314 and the PEG-35. With decrease in the proportion of PEG-35 in the wastewater, the degree of extraction of berol-visko 314 rises to 80% at a flotation time of not over 60 min.A calcium ion content of up to 950 mg/liter in wastewater exerts no effect on the degree of extraction of the NSAS.Translated from Khimicheskie Volokna, No. 1, pp. 52–54, January–February, 1988.     

Mass transfer in the dissolution of solid carbon dioxide in liquid oxygen in a unit with a mixing device

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 7, pp. 19–20, July, 1989.     

Theory and Practice of Mixing: A Review

An analytical review of achievements in the field of the design of industrial equipment for mixing liquids, suspensions, and gas–liquid dispersions is presented. Various methods of mixing are discussed: mechanical, pneumatic, jet, vibrational, and magnetic. Nonconventional mixing devices with reversible movement of mixer parts, as well as static, rotary, rotor-stator, vortex, and ultrasonic devices, are considered. Miniaturization of equipment and micromixers were also reviewed.     

Study of \{ 11\bar{2} 1\} Twinning in α-Ti by EBSD and Laue Microdiffraction

Activity of the $ \{ 11\bar{2} 1\} \langle \bar{1} \bar{1} 26 \rangle $ extension twinning (T2) mode was analyzed in a commercial purity Ti sample after 2 pct tensile strain imposed by four-point bending. The sample had a moderate c-axis fiber texture parallel to the tensile axis. Compared with the many $ \{ 10\bar{1} 2\} \langle \bar{1} 011 \rangle $ extension (T1) twins that formed in 6 pct of the grains, T2 twins were identified in 0.25 pct of the grains by scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) maps. Most of the T2 twins exhibited irregular twin boundaries (TBs) on one side of the twin. High-resolution EBSD revealed both intermediate orientations at some matrix/twin interfaces and substantial lattice rotation within some T2 twins. Interactions between matrix 〈c + a〉 dislocations $ \frac{1}{3} \langle 1\bar{2} 13 \rangle $ and a $ \{ 11\bar{2} 1\} $ T2 twin were investigated by combining SEM/EBSD slip trace characterization and Laue microdiffraction peak streak analysis. 〈c + a〉 dislocations that originally glided on a pyramidal plane in the matrix were found on other planes in both the matrix and the twin, which was attributed to extensive cross-slip of the screw component, whose Burgers vector was parallel to the twinning plane. On the other hand, thickening of the twin could engulf some pile-up edge components in front of the TB. During this process, these 〈c + a〉 dislocations transmuted from a pyramidal plane $ (0\bar{1} 11) $ in the matrix to a prismatic plane $ (\bar{1} 010)_{\text{T}} $ in the twin lattice. Finally, possible mechanisms for the nucleation and growth of T2 twins will be discussed.