Temporal Evolution of γ Precipitate in Haynes 282 During Ageing – Growth and Coarsening Kinetics, Solute Partitioning and Lattice Misfit

2020 ◽  
Author(s):  
Shreya Mukherjee ◽  
Sudip Kumar Sarkar ◽  
Sarita Ahlawat ◽  
Aniruddha Biswas ◽  
Gopi K. Mandal ◽  
...  
2000 ◽  
Vol 6 (S2) ◽  
pp. 360-361
Author(s):  
B. Hyde ◽  
W.T. Reynolds

The focus of our study is to demonstrate experimentally how elastic stress effects diffusion behavior and coarsening kinetics in a two-phase binary alloy. This work, based on the theory of Cahn and Kobayashi, focuses on elastic stresses in a thin plate. For the case of phase separation with lattice misfit between solute-rich and solute-poor phases, the diffusion of solute distorts the host lattice and causes elastic stress in the matrix. If the plate is sufficiently thin, the stress can cause the plate to buckle. The buckling stress biases the direction of diffusion, which increases the bending stress even further. Thus, the diffusion and the buckling stress are coupled; each affects the other. The interplay between the two is easiest to observe in a solution in which the solute and solvent have high misfit.


2016 ◽  
Vol 113 ◽  
pp. 185-189 ◽  
Author(s):  
S. Meher ◽  
L.J. Carroll ◽  
T.M. Pollock ◽  
M.C. Carroll

Author(s):  
H. L. Tsai ◽  
J. W. Lee

Growth of GaAs on Si using epitaxial techniques has been receiving considerable attention for its potential application in device fabrication. However, because of the 4% lattice misfit between GaAs and Si, defect generation at the GaAs/Si interface and its propagation to the top portion of the GaAs film occur during the growth process. The performance of a device fabricated in the GaAs-on-Si film can be degraded because of the presence of these defects. This paper describes a HREM study of the effects of both the substrate surface quality and postannealing on the defect propagation and elimination.The silicon substrates used for this work were 3-4 degrees off [100] orientation. GaAs was grown on the silicon substrate by molecular beam epitaxy (MBE).


Author(s):  
S.R. Summerfelt ◽  
C.B. Carter

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.


2008 ◽  
Author(s):  
Elena Torres Alvarez ◽  
Alicia Escribano ◽  
María Jesús. Turrero ◽  
Pedro Luis. Martín ◽  
Javier Peña ◽  
...  
Keyword(s):  

2002 ◽  
Vol 715 ◽  
Author(s):  
Zhi-Feng Huang ◽  
Rashmi C. Desai

AbstractThe morphological and compositional instabilities in the heteroepitaxial strained alloy films have attracted intense interest from both experimentalists and theorists. To understand the mechanisms and properties for the generation of instabilities, we have developed a nonequilibrium, continuum model for the dislocation-free and coherent film systems. The early evolution processes of surface pro.les for both growing and postdeposition (non-growing) thin alloy films are studied through a linear stability analysis. We consider the coupling between top surface of the film and the underlying bulk, as well as the combination and interplay of different elastic effects. These e.ects are caused by filmsubstrate lattice misfit, composition dependence of film lattice constant (compositional stress), and composition dependence of both Young's and shear elastic moduli. The interplay of these factors as well as the growth temperature and deposition rate leads to rich and complicated stability results. For both the growing.lm and non-growing alloy free surface, we determine the stability conditions and diagrams for the system. These show the joint stability or instability for film morphology and compositional pro.les, as well as the asymmetry between tensile and compressive layers. The kinetic critical thickness for the onset of instability during.lm growth is also calculated, and its scaling behavior with respect to misfit strain and deposition rate determined. Our results have implications for real alloy growth systems such as SiGe and InGaAs, which agree with qualitative trends seen in recent experimental observations.


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