TY - JOUR
TI - Characterization of metal precipitates in magnesium oxide
AU - Narayan, J.
AU - Chen, Y.
AU - Moon, R. M.
AU - Carpenter, R. W.
T2 - Philosophical Magazine A
AB - Abstract A method, based on subtractive coloration or high-temperature reduction, has been developed to produce metal precipitates or colloids in oxides. The structure, symmetry, morphology and composition of precipitates were analysed by analytical electron microscopy and neutron scattering techniques. In the MgO: Ni system, the colloids were coherent nickel precipitates having a f.c.c. structure (ao = 3·52 Å), and occasionally a b.c.c. structure (ao = 2·88Å). The coherent precipitates were found to have either ⟨100⟩m‖⟨111⟩p or ⟨100⟩m‖⟨100⟩p matrix-precipitate relationship, depending on the high-temperature reduction treatment. From the neutron-magnetic-scattering measurements, the ratio of magnetic to nuclear scattering amplitudes for the (111) precipitate reflection was determined to be 17% below the value for pure nickel, indicating the presence of a magnetically ‘dead’ layer around the precipitates, a small amount of impurities incorporated into the precipitates, or a small fraction of another phase of nickel.
DA - 1984/8//
PY - 1984/8//
DO - 10.1080/01418618408234929
VL - 49
IS - 2
SP - 287-300
J2 - Philosophical Magazine A
LA - en
OP -
SN - 0141-8610 1460-6992
UR - http://dx.doi.org/10.1080/01418618408234929
DB - Crossref
ER -
TY - JOUR
TI - The elastic stress field associated with a curved dislocation in a two-phase medium with a planar interface
AU - Jagannadham, K.
T2 - Materials Science and Engineering
AB - Abstract The elastic field associated with an infinitestimal dislocation segment situated parallel to a planar interface in one of the phases of a two-phase medium is determined by means of surface dislocation analysis. In particular. the continuity conditions at the interface resulting from the tractions and the displacement gradients due to the elastic field of an infinitesimal segment are satisfied using a continuous distribution of surface dislocations on either side of the interface. The resulting dislocation distributions are used to determine the tractions at the interface. Furthermore, the relation between an interface dislocation and surface dislocations situated in either phase is derived. The significance of these results to structural changes at the interface is emphasized.
DA - 1984///
PY - 1984///
DO - 10.1016/0025-5416(84)90164-2
VL - 63
IS - 1
SP - 65-80
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0021388319&partnerID=MN8TOARS
ER -
TY - JOUR
TI - DISLOCATION CLIMB VIA JOG MOVEMENT AT THE TIP OF A CRACK.
AU - Jagannadham, K.
AU - Raghavan, K.S.
T2 - Transactions of the Indian Institute of Metals
DA - 1984///
PY - 1984///
VL - 37
IS - 4
SP - 357-360
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0021470339&partnerID=MN8TOARS
ER -
TY - JOUR
TI - THEORETICAL-ANALYSIS OF THE CHANNEL DIE COMPRESSION TEST .1. GENERAL-CONSIDERATIONS AND FINITE DEFORMATION OF FCC CRYSTALS IN STABLE LATTICE ORIENTATIONS
AU - SUE, PL
AU - HAVNER, KS
T2 - JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
AB - An extensive theoretical investigation of f.c.c. crystals under [110] loading in the channel die compression test is presented. Two lattice orientations known from experiment to be stable relative to the channel axes, through large deformations, are investigated for each of four hardening laws. These are Taylor's classical isotropic hardening rule, a 2-parameter empirical rule from the metallurgical literature, the “simple theory” of anisotropic latent hardening(Havner and Shalaby, Proc. R. Soc. A 358,47 (1977)), and a modification of the simple theory proposed by pfirce et al., Acta Met.30, 1087 (1982). Predictions of active systems, equal multiple-slip and consequent lattice stability, finite shape change, and lateral constraint stress are the same for all theories, corresponding to minimum rate of plastic work, and are in general agreement with experiments on copper crystals by Wonsiewicz and Chin, Met. Trans.1, 2715 (1970) and Wonsiewiczet al., Met. Trans.2, 2093 (1971). The predictions of latent hardening differ among the theories, however, depending upon whether there is relative rotation of material and lattice. The potential significance of experimental studies of latent hardening in these particular stable lattice orientations is emphasized.
DA - 1984///
PY - 1984///
DO - 10.1016/0022-5096(84)90029-2
VL - 32
IS - 6
SP - 417-442
SN - 0022-5096
ER -
TY - JOUR
TI - 1ST-ORDER AND 2ND-ORDER ANALYSIS OF AXIALLY LOADED CRYSTALS IN N-FOLD SYMMETRY
AU - HAVNER, KS
T2 - PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
AB - A comprehensive theoretical investigation of multiple slip in axially tensile-loaded f.c.c. crystals in n -fold symmetry positions ( n = 4, 6, 8) is presented. The analysis is complete to second order in terms of series expansions of all variables in the prescribed small load increment. In the first part of the paper, general kinematic relations and slip-system inequalities are given, and several new results discovered that apply independently of hardening rule and degree of symmetry. Subsequent sections contain extensive firsthand second-order analyses corresponding to four specific hardening theories, including Taylor's classical isotropic rule and the ‘ simple theory’ of anisotropic latent hardening. For minimum work, unifying relations are found connecting a generic hardening parameter, its rate of change with load, and the first and second derivatives of axial stretch that hold for all four theories.
DA - 1984///
PY - 1984///
DO - 10.1098/rsta.1984.0039
VL - 311
IS - 1518
SP - 469-493
SN - 1364-503X
ER -