scholarly journals Transformation Texture Analysis of BCC and BCT Ferrous Martensite

1993 ◽  
Vol 22 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Hirofumi Miyaji ◽  
Ei-Ichi Furubayashi
Keyword(s):  
Crystal Orientation ◽  
Thin Sheet ◽  
Parent Phase ◽  
External Stress ◽  
Strain Component ◽  
X Ray ◽  
Transformation Texture ◽  
Twinning Shear ◽  
Constraint Stress ◽  
Bain Strain

The theoretical prediction of transformation textures, that developed in thin sheet without external stress, was carried out based on the Bain-Strain and Twinning-Shear model, respectively. To examine the validity of the prediction, the experiments were conducted with X-ray pole figure method on Fe-30Ni and Fe-30Ni-0.8C alloy sheets. The results obtained are as follows:(1) Variant selection phenomenon depends on the crystal orientation of the parent phase and on the Bain strain in the martensitic transformation.(2) The effect of the anisotropic constraint stress on the shear deformation involved in the lattice change and on the Bain distortion appears most remarkably in the BCT martensite transformed from the cube textured parent phase.(3) It became clear that such a variant that has the largest Bain strain component to the sheet normal, that is, the variant, of which the Bain distortion is prevented least of all by the anisotropic constraint stress, forms predominantly.

scholarly journals Effect of Specimen Size on the Variant Selection in Martensitic Transformation

1990 ◽  
Vol 12 (4) ◽  
pp. 189-197 ◽  
Author(s):  
Hirofumi Miyaji ◽  
Ei-Ichi Furubayashi
Keyword(s):  
Martensitic Transformation ◽  
Thin Sheet ◽  
Parent Phase ◽  
Variant Selection ◽  
Strain Component ◽  
Selection Models ◽  
X Ray ◽  
Ni Alloy ◽  
Cold Rolling And Annealing ◽  
Constraint Stress

In thin sheet the anisotropy of the internal stress due to constraint by the surrounding parent phase which will be abbreviated as “constraint stress,” seems to occur during the martensitic transformation and the variant selection is expected also in the transformation without external stress. To verify this, the textures were measured by X-ray pole figure method on the γ and α phase which were developed in thin sheet of Fe-30 Ni alloy prepared by severe cold rolling and annealing followed by subzero quenching to liquid Nitrogen. Experimental data were analyzed with conventional variant selection models. The results obtained are as follows: (a) Variant selection phenomenon was clearly observed and the results could be explained with conventional variant selection models. (b) It is expected that different results occur between the conventional variant selection models when the martensitic transformation occurs accompanying the strain component of |ε1|≦|ε2|, where ε1 is the strain along the Bain compression axis and ε2 is along the perpendicular axis.

Strains in light-ion-implanted polycrystals: influence of grain orientation

2012 ◽  
Vol 45 (4) ◽  
pp. 826-833 ◽  
Author(s):  
Axel Richard ◽  
Hervé Palancher ◽  
É. Castelier ◽  
J.-S. Micha ◽  
M. Gamaleri ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Grain Orientation ◽  
Crystal Orientation ◽  
Radiation Effects ◽  
Strong Dependence ◽  
Strain Tensor ◽  
Strain Component ◽  
X Ray Diffraction ◽  
X Ray ◽  
Out Of Plane

The implantation of He ions in UO2polycrystals induces a strain in the implanted layer which can be characterized using Laue micro X-ray diffraction (µ-XRD). The strain tensor resulting from the ion implantation may not be reduced to a single out-of-plane strain component: it also has nonzero shear components. Their strong dependence upon crystal orientation is modeled using elasticity theory. This work demonstrates the potential of Laue µ-XRD for characterizing radiation effects in materials.

scholarly journals Internal stress created by plastic flow in mild steel, and stress-strain curves for the atomic lattice of higher carbon steels

1944 ◽  
Vol 182 (991) ◽  
pp. 404-414 ◽  
Keyword(s):  
Mild Steel ◽  
Internal Stress ◽  
Plastic Flow ◽  
Carbon Steels ◽  
External Stress ◽  
Stress Strain ◽  
Atomic Lattice ◽  
X Ray ◽  
Elastic Range ◽  
Residual Strains

In previous work, stress-strain curves for the atomic lattice of certain metals have been obtained from X-ray diffraction measurements of the lattice dimensions of test specimens under tension or compression, and it has been shown that when the external yield stress is exceeded, there is a systematic departure from Hooke’s Law. It is pointed out in the present paper that this departure indicates that the external applied stress above the yield is no longer balanced primarily by simple displacement of the atoms but also by a new type of secondary internal stress brought about by the process of plastic flow; and that this secondary stress, being of a permanent nature, can be measured by the residual lattice strains exhibited by the lattice after removal of the external stress. These residual strains are measured in various directions to the stress direction for mild steel subjected to tension, and it is shown that the lattice after tension exhibits a longitudinal compression and a transverse expansion in the ratio of 2:1, which means that the density of the material is thereby kept constant. Comparisons of X-ray and mechanical measurements further show that the hysteresis loop exhibited by the external stress-strain curve of mild steel after overstrain can disappear and the linear elastic relation be recovered without any corresponding change in the internal stress, which is therefore a more fundamental physical property. It is also shown that when the elastic range is extended by overstrain in tension, there is no symmetrical increase in the elastic range in subsequent compression, thus confirming the existence and direction of the secondary internal stress. Finally, the lattice stress-strain curves are also obtained for a 0.4 % C steel (partially pearlitic) and a 0.8 % C steel (pearlitic), and by comparison with the results on pure iron and 0.1 % C steel (annealed) it is shown that the maximum residual internal strain developed by the lattice increases markedly with the fineness to which the crystallites can be broken down by the plastic deformation.

Synthesis of Supergrowth VACNTs and Nanostructured ZnO by Immerse Method

2011 ◽  
Vol 312-315 ◽  
pp. 1044-1048
Author(s):  
Salina Muhamad ◽  
Abu Bakar Suriani ◽  
Mohamad Zainizan Sahdan ◽  
Anuar Ahmad ◽  
Yosri M. Siran ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Zinc Nitrate ◽  
Zinc Nitrate Hexahydrate ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
Vertically Aligned Carbon Nanotubes ◽  
X Ray ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
Physical Changes

In this paper, the study of supergrowth VACNTs after being immersed in zinc oxide solution were presented. Vertically aligned carbon nanotubes (VACNTs) were first deposited on silicon with the orientation of [1 0 0] before being immersed in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine. Physical changes have been observed by scanning electron microscopy, SEM in the VACNTs, where the significant expansion of length of up to almost 0.8 mm was achieved after the immersion of 4.5 hr. The supergrowth of VACNTs was observed and analyzed by energy dispersive x-ray spectroscopy, EDX to substantiate the incorporation of CNTs and ZnO of the sample. Raman spectroscopy and x-ray diffraction, XRD were used to inspect the crystal orientation to support our findings.

scholarly journals Microscopic Stress and Strain Evolved in a Twinning-Induced Plasticity Fe-Mn-C Steel

2014 ◽  
Vol 996 ◽  
pp. 135-140
Author(s):  
Shigeru Suzuki ◽  
Shigeo Sato ◽  
Koji Hotta ◽  
Eui Pyo Kwon ◽  
Shun Fujieda ◽  
...  
Keyword(s):  
Strain Distribution ◽  
Crystal Orientation ◽  
Fem Simulation ◽  
Tensile Loading ◽  
Stress And Strain ◽  
X Ray Diffraction ◽  
Principal Stresses ◽  
Orientation Data ◽  
Tensile Direction ◽  
X Ray

White X-ray diffraction with micro-beam synchrotron radiation was used to analyze microscopic stress evolved in coarse grains of a twinning-induced plasticity Fe-Mn-C steel under tensile loading. In addition, electron backscatter diffraction (EBSD) was used to determine the crystal orientation of grains in the polycrystalline Fe-Mn-C steel. Based on these orientation data, the stress and strain distribution in the microstructure of the steel under tensile loading was estimated using FEM simulation where the elastic anisotropy or the crystal orientation dependence of the elasticity was taken into account. The FEM simulation showed that the strain distribution in the microstructure depends on the crystal orientation of each grain. The stress analysis by the white X-ray diffraction indicated that the direction of the maximum principal stresses at measured points in the steel under tensile loading are mostly oriented toward the tensile direction. This is qualitatively consistent with the results of by the FEM simulation, although absolute values of the principal stresses may contain the effect of heterogeneous plastic deformation on the stress distribution.

Effect of Annealing Temperature and External Tensile Stress on Negative Thermal Expansion to Cold Rolled Ti–23Nb–0.7Ta–2Zr Alloy

2020 ◽  
Vol 12 (9) ◽  
pp. 1409-1412
Author(s):  
Jeong-Tae Moon ◽  
Tae-Hyun Nam
Keyword(s):  
Thermal Expansion ◽  
Annealing Temperature ◽  
Negative Thermal Expansion ◽  
Constant Load ◽  
External Stress ◽  
Expansion Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Rolled ◽  
The Difference

The effect of annealing temperature and external stress on the thermal expansion of a Ti–23Nb–0.7Ta–2Zr alloy were investigated by means of thermal expansion tests under constant load and X-ray diffraction (XRD). Negative thermal expansion (NTE), which is a shrinkage during heating, was observed in both a cold rolled and annealed specimens. The intensity of (200)β peak decreased while that of (211)β peak increased as the annealing temperature increased. The difference in expansion rate between 50 °C and 250 °C is found to decrease with an increasing annealing temperature from 600 °C to 800 °C, above which it kept almost constant. The expansion rate decreased as the applied stress increased.

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