作者: Kee Joo Kim, Joo Sung Kim

摘要: To fabricate the aluminum alloys with good drawability, the textures evolution of the
AA5182 sheets after rolling and subsequent annealing was studied. The measurement of the
deformation textures was carried out for the sheets with high reduction ratio and the change of the
recrystallization texture was investigated after heat-treatments of the rolled sheets. Rolling without
lubrication and subsequent annealing led to the formation of favorable rot-CND {001}<110> and
γ-fiber ND//<111> textures in AA5182 sheets. From the results, the γ-fiber ND//<111> component
well evolved during rolling at high reduction ratio. Among shear deformation textures, the γ-fiber
ND//<111> was not rotated in holding time until 7,200 seconds at 350. The Monte-Carlo technique
was used and could be representatively simulated textures evolution during recrystallization.

1421

作者: Irina V. Belova, Graeme E. Murch

摘要: In this paper, we show how lattice–based random walks of virtual particles directed by
Monte Carlo methods (Lattice Monte Carlo) can be used to address a variety of complex
phenomenologically mass diffusion problems. Emphasis is put on the practical details of doing the
calculations. It is shown how concentration depth profiles can be determined: this is exemplified
with diffusion in the presence of isolated dislocation pipes, grain boundary slabs, and oxygen
segregation at interfaces in metal-ceramic oxide composites. It is also shown how effective
diffusivities can be determined in materials. We also show how temperature profiles and the
effective thermal conductivity can be determined for the thermal diffusion analogue of mass
diffusion. A detailed comparison is made in one case with the results of the Finite Element method.

1

作者: Irina V. Belova, Andreas Öchsner, Nilindu Muthubandara, Graeme E. Murch

摘要: The presence of atomic oxygen at internal metal-ceramic oxide interfaces significantly
affects the physical properties of the interfaces which in turn affects the bulk properties of the
material. This problem is addressed for the model composite system Ag-MgO from a
phenomenological point of view using a lattice-based Monte Carlo method and a finite element
method extended with special user-subroutines. We simulate the time dependence of oxygen depth
and contour profiles. We are able to show very good agreement between these two methods.

29

作者: Wojciech Wajda, Henryk Paul

摘要: The paper describes the mechanism of deformation at 77 K of pure aluminum bicrystals of different grain orientations. The following orientations were selected: {100}/{110} (cube/Goss) and - {100}/{100} (cube/shear) to represent the unstable vs. stable and the unstable vs. unstable behaviours, respectively. The bicrystalline samples were deformed in the plane strain conditions with the use of a channel-die immersed inside a reservoir with liquid nitrogen. The low temperature deformation increases the tendency to form plain strain inhomogeneities of the deformation in the grains with an unstable orientation. In both sets of crystallite compositions, the grain boundary was situated perpendicularly to the compression plane. A particular interest was paid to the analysis of the tendencies of the crystal lattice rotations near the grain boundary and the description of the deformation behaviour of the material in the macro- scale (hardening behaviour). A detailed analysis of the crystal lattice rotations was possible with the application of the local orientation measurements by means of scanning and transmission electron microscopes, equipped with the electron backscattered diffraction and convergent beam electron diffraction facility, respectively. The experimental results of the local orientation measurements were used to evaluate the accuracy of the numerical prediction of the macro-scale behaviour of bi-crystalline samples by a single Cristal Plasticity Model. The investigation shows that the crystallites behave essentially as single crystals in the same deformation conditions. Due to the similar hardening behaviour of the investigated crystallites (similar values of the Taylor factors) the grain boundary remains unchanged. The calculated lattice rotations are similar to those observed experimentally. Key words: aluminium bi-crystals, texture, microstructure, single crystal plasticity model

108

作者: Chun Xia Yang, Ya Ying Wu, Wei Jun Yang

摘要: Regular tessellation theory was firstly introduced to deconstruct cells and partition masonry periodically in two dimensions in this paper, the method of regular deconstruction of masonry structures was proposed. In addition, the relationship in mathematical models between the basic cells and RVE was explored, the basic cells and the corresponding RVE boundary and initial conditions was derived.

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