On the kinetics of oriented growth of two-phase colonies of platelet grains in the presence of second-phase particles phase

2014 ◽  
Vol 115 (7) ◽  
pp. 655-660
Author(s):  
V. E. Ol’shanetskii ◽  
Yu. I. Kononenko
2016 ◽  
Vol 35 (10) ◽  
pp. 1005-1011
Author(s):  
T. J. Pan ◽  
J. Chen ◽  
Y. X. He ◽  
W. Wei ◽  
J. Hu

AbstractThe oxidation behavior of grain-refined Cu–7.0 Cr alloy (GR Cu–7.0 Cr) in air at 973–1,073 K was investigated in comparison with normal casting Cu–7.0 Cr alloy (CA Cu–7.0 Cr). The oxidation of CA Cu–7.0 Cr alloy nearly followed parabolic law, while the oxidation kinetics of GR Cu–7.0 Cr slightly deviated from parabolic law. Both alloys almost produced multi-layered scales consisting of the outer layer of CuO and the inner layer of mixed Cr2O3 and Cu2O oxides plus internal oxidation zones of chromium. The grain-refined Cu–7.0 Cr alloy produced a more amount of Cr2O3 in the inner layer of the scale, and thus was oxidized at much lower oxidation rate than that of CA Cu–7.0 Cr with normal grain size. The experimental results indicated that the differences in oxidation behavior between two alloys may be ascribed to the different size and spatial distribution of the second-phase particles and the reactive component contents in localized zone.


2014 ◽  
Vol 598 ◽  
pp. 8-12
Author(s):  
K.R. Phaneesh ◽  
Anirudh Bhat ◽  
Gautam Mukherjee ◽  
Kishore T. Kashyap

Large scale Potts model Monte Carlo simulation was carried on 3-dimensional square lattices of 1003 and 2003 sizes using the Metropolis algorithm to study grain growth behavior. Simulations were carried out to investigate both growth kinetics as well as the Zener limit in two-phase polycrystals inhibited in growth by second phase particles of single-voxel size. Initially the matrices were run to 10,000 Monte Carlo steps (MCS) to check the growth kinetics in both single phase and two-phase poly-crystals. Grain growth exponent values obtained as a result have shown to be highest (~ 0.4) for mono-phase materials while the value decreases with addition of second phase particles. Subsequently the matrices were run to stagnation in the presence of second phase particles of volume fractions ranging from 0.001to 0.1. Results obtained have shown a cube root dependence of the limiting grain size over the particle volume fraction thus reinforcing earlier 3D simulation efforts. It was observed that there was not much difference in the values of either growth kinetics or the Zener limit between 1003 and 2003 sized matrices, although the results improved mildly with size.


1994 ◽  
Vol 364 ◽  
Author(s):  
Gengxiang Hu ◽  
Jian Sun ◽  
Xiaojun Weng ◽  
Tong Li ◽  
Shipu Chen

AbstractSince the L12 structured Al3Ti alloy exists only in a narrow compositional range, further alloying of the single phase Ll2 alloy to improve its property seems hardly successful. Developing two-phase or multiphase Al3Ti alloys may be an effective approach for strengthening and toughening. In this article, a new type of Al3Ti-based alloy which has a Ll2 matrix with precipitates of a second phase is reported. The quaternary alloys based on Al67Mn8Ti25, and modified with Nb additions, consist of an Ll2 matrix and DO22 second phase particles in the annealed state, but the second phase can be dissolved by solution treatment and precipitated during high temperature aging. Remarkable strenghtening and promising compressive ductility were exhibited by the experimental alloy. The influence of composition on the microstructure and properties of the alloys are reported also.


2012 ◽  
Vol 715-716 ◽  
pp. 23-32 ◽  
Author(s):  
John F. Humphreys ◽  
Pete S. Bate ◽  
Ali Gholinia ◽  
Ian Brough

The effect of second-phase particles on the deformation and annealing behaviour of metals is re-assessed in the light of some new techniques. Using an EBSD method which provides much improved angular resolution, the effect of small non-deformable particles on the homogeneity of the deformation microstructure has been quantified. The presence of micron sized second-phase particles alters the deformation microstructure adjacent to particles, and a 3-d investigation of the deformation structures associated with large (>1μm) second-phase particles in cold rolled aluminium alloys has been carried out using 3-d FIB sectioning combined with EBSD, and the microstructures compared with the predictions of 3-d CPFEM modelling. The effects of grain orientation, strain and particle size have been investigated, and the results compared with earlier TEM investigations of such microstructures.


1983 ◽  
Vol 105 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Y. Tada ◽  
M. Oyane ◽  
S. Shima ◽  
T. Sato ◽  
M. Omura

Strength and deformation of two-phase materials are investigated by the upper bound approach in relation to the volume fraction of the second-phase particles, yield strength ratio and bond strength between the constituents, shape of the particles, and environmental hydrostatic pressure. The stress-strain curve of a two-phase material is estimated as an application of this method. The calculated results are in good agreement with experimental ones.


A statistical theory of a two-phase material consisting of a brittle matrix with a dispersion of tougher second-phase particles is developed. In this material, failure does not occur immediately a microfracture is initiated at a flaw in the matrix. Stable cracks spanning the second-phase particles are possible and many will form before final failure occurs, especially in large specimens. The expected number of such cracks that are formed at any stress level is calculated. The statistical strength distribution for specimens under both tension and bending is obtained. It is shown that in a two-phase material the ratio of bending to tensile strength of a beam decreases with size, whatever flaw-size distribution is assumed.


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