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Equal - Channel Angular Pressing : A Novel Tool for Microstructural Control
NEMOTO, Minoru,Horita, Zenji,Furukawa, Minoru,Langdon, Terence G . 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.6
The principles of equal-channel angular (ECA) pressing are reviewed. It is demonstrated that this processing procedure is capable of introducing an ultrafine grain size into bulk materials and the precise nature of the microstructure is dependent upon the total strain introduced by the pressing. When the strain is sufficiently high, it is possible to achieve very high tensile ductilities at high strain rates, thereby providing the potential for substantially increasing the viability of superplastic forming in the metal forming industry.
Factors Influencing Microstructural Development in Equal-Channel Angular Pressing
Furukawa, Minoru,Horita, Zenji,Langdon, Terence G. 대한금속재료학회 2003 METALS AND MATERIALS International Vol.9 No.2
Processing through the imposition of severe plastic deformation (SPD) provides an opportunity for achieving very significant grain refinement in bulk materials. Although different SPD procedures are available, the process of equal-channel angular pressing (ECAP) is especially attractive because it can be scaled easily to produce relatively large samples. This paper describes the principles of ECAP processing and demonstrates the potential for achieving unusual mechanical properties in the samples subjected to ECAP. Special emphasis is placed on the possibility of attaining a high strain rate superplastic forming capability in the as-pressed materials: examples are presented for an Al-Mg-Sc alloy prepared in the laboratory by casting and for a commercial Al-2024 alloy.
Kaneko, Kenji,Moon, Won-Jin,Inoke, Koji,Horita, Zenji,Ohara, Satoshi,Adschiri, Tadafumi,Abe, Hiroya,Naito, Makio Elsevier 2005 Materials science & engineering. properties, micro Vol.403 No.1
<P><B>Abstract</B></P><P>TiO<SUB>2</SUB>–Ag nanocomposite particles were prepared by spray pyrolysis of TiO<SUB>2</SUB> (7nm) dispersed AgNO<SUB>3</SUB> solution. The structures and morphologies of powders were carefully characterized by combination of transmission electron microscopy (TEM) and three-dimensional electron tomography (3D-ET). It was clearly demonstrated by 3D-ET that the TiO<SUB>2</SUB>–Ag nanocomposite particle was consisted of well-dispersed Ag nanoparticles within TiO<SUB>2</SUB> matrix. Furthermore, it was shown by high-resolution TEM that the spray pyrolysis was capable of fabricating Ag particles with a few nm in size.</P>
Edalati, Kaveh,Lee, Dong Jun,Nagaoka, Takashi,Arita, Makoto,Kim, Hyoung Seop,Horita, Zenji,Pippan, Reinhard JAPAN INSTITUTE OF METALS 2016 MATERIALS TRANSACTIONS Vol.57 No.4
<P>Hydrostatic pressure is a significant parameter influencing the evolution of microstructure and phase transformations in the high-pressure torsion (HPT) process. Currently, there are significant arguments relating to the magnitude of the real hydrostatic pressure during the process. In this study, phase transformations in bismuth, copper and titanium combined with the finite element method (FEM) were employed to determine the real pressure in processing disc samples by HPT. Any break in the variation of steady-state hardness (monitored experimentally by in-situ torque and temperature rise measurements) versus pressure was considered as a phase transition. FEM simulations show that the hydrostatic pressure is reasonably isotropic but decreases with increasing distance from the disc center and remains unchanged across the disc thickness. Both experiments and simulations indicate that the mean hydrostatic pressure during HPT processing closely corresponds to the compressive load over the disc area plus the contact area between the anvils.</P>