Grain-Boundary Sliding and Axial Strain during Diffusional Creep

Metal Science ◽  
1975 ◽  
Vol 9 (1) ◽  
pp. 141-144 ◽  
Author(s):  
R. C. Gifkins ◽  
T. G. Langdon ◽  
D. McLean
Keyword(s):  
Grain Boundary ◽  
Axial Strain ◽  
Grain Boundary Sliding ◽  
Diffusional Creep ◽  
Boundary Sliding

scholarly journals Diffusion-Accommodated Grain Boundary Sliding in a Polycrystal

1990 ◽  
Vol 196 ◽  
Author(s):  
P. M. Hazzledine ◽  
J. H. Schneibel
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Grain Boundary Sliding ◽  
Diffusional Creep ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Material Deposition ◽  
Two Dimensional Model ◽  
Boundary Sliding ◽  
Coble Creep

ABSTRACTA two-dimensional model for diffusional creep (Coble creep) and diffusionaccommodated grain boundary sliding in polycrystals has been developed. The results obtained for small symmetrical clusters of grains reproduce Spingam and Nix's work [Acta Metall. 2M, 1389 (1978)]. For clusters of irregularly shaped grains the material deposition and removal rates, the fluxes along the grain boundaries, the grain boundary tractions as well as the grain boundary sliding rates are irregular and can all be calculated.

scholarly journals Анализ механизмов уплотнения термоэлектрических порошков скуттерудитов и сплавов Гейслера в процессе активированного полем спекания

2021 ◽  
Vol 55 (12) ◽  
pp. 1132
Author(s):  
А.С. Тукмакова ◽  
Н.И. Хахилев ◽  
Д.Б. Щеглова ◽  
В.Д. Насонов ◽  
А.П. Новицкий ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Heusler Alloys ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Creep Mechanism ◽  
Diffusional Creep ◽  
Creep Model ◽  
Ceramic Powders ◽  
Boundary Sliding ◽  
Power Law Creep

The analysis of the shrinkage rate of powders, based on the power-law creep model of a porous body, was carried out in this paper to calculate the compaction parameters of CoSb3-based skutterudites and Fe2VAl-based Heusler alloys within field-activated sintering. It was indicated that this method, which had already been used for metal and ceramic powders, is applicable for thermoelectric powders. The values of strain rate sensitivity were obtained, and the corresponding powder compaction mechanisms have been defined. The main creep mechanism for skutterudites was found to be a dislocation climb, that later was replaced by grain boundary sliding, and the last sintering stage was associated with diffusional creep. The main creep mechanism for Heusler alloys was grain boundary sliding, later replaced by diffusional creep.

A formulation for anisotropy in diffusional creep

1992 ◽  
Vol 436 (1896) ◽  
pp. 187-196 ◽  
Keyword(s):  
Grain Boundary ◽  
Elastic Anisotropy ◽  
Creep Behaviour ◽  
Grain Boundary Sliding ◽  
Diffusional Creep ◽  
Sources And Sinks ◽  
Boundary Sliding ◽  
Compliance Matrices

Grain shape can introduce anisotropy in creep which depends on the diffusion of vacancies between grain boundary sources and sinks. Such anisotropy is examined to determine the rate of creep under multiaxial stresses both for lattice and grain boundary diffusion. Noting the role of grain boundary sliding in this form of creep it is shown that, with some approximations that only become significant in an identified case, complete and fully self-consistent formulae can be derived for the rate of creep in terms of grain dimensions. The results are presented in the form of compliance matrices which are analogous to those that have a well-established role in the characterization of elastic anisotropy. A comparable usefulness of these ‘creep compliance coefficients’ is envisaged in evaluating anisotropic diffusional creep behaviour and a similar approach can be extended to more general cases where creep rates may be interface controlled.

Mechanisms-based constitutive equations for the superplastic behaviour of a titanium alloy

1996 ◽  
Vol 31 (3) ◽  
pp. 187-196 ◽  
Author(s):  
M Zhou ◽  
F P E Dunne
Keyword(s):  
Titanium Alloy ◽  
Grain Boundary ◽  
Grain Growth ◽  
Constitutive Equations ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Diffusional Creep ◽  
Dislocation Creep ◽  
Boundary Sliding

Mechanisms-based constitutive equations are proposed for the high-temperature behaviour of a class of titanium alloys, for which the deformation mechanisms include diffusional creep, grain boundary sliding, dislocation creep and grain growth. A computational procedure has been developed for the determination of the constitutive equations from a material database. The constitutive equations and the procedure for their determination have been validated by modelling the behaviour of the titanium alloy Ti-6Al-4V at 927°C. It is shown that the procedure developed for the determination of the mechanisms-based constitutive equations can be used to identify the important deformation mechanisms in operation for particular stress, temperature and strain rate conditions. For the case of the Ti-6Al-4V material, the procedure developed correctly predicts the material hardening due to grain growth and indicates that an additional hardening mechanism operates. In addition, the procedure is able to identify grain boundary sliding as a predominant deformation mechanism. The constitutive equations, which are generic in nature, and the procedure for their determination are applicable over a range of materials and are suitable for modelling the macroscopic and the important microscopic aspects of material behaviour during processing. The equations may be readily determined using the procedure presented, which is highly suitable for development as an expert system, to completely automate the process.

Role of grain-boundary sliding in diffusional creep of polycrystals

1998 ◽  
Vol 83 (12) ◽  
pp. 7547-7552 ◽  
Author(s):  
T. Mori ◽  
S. Onaka ◽  
K. Wakashima
Keyword(s):  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Diffusional Creep ◽  
Boundary Sliding

Sinter-Forging of Nanocrystalline TiO2

1992 ◽  
Vol 286 ◽  
Author(s):  
H.J. HÖfler ◽  
R.S. Averback
Keyword(s):  
Grain Boundary ◽  
Threshold Stress ◽  
Grain Boundary Sliding ◽  
Constitutive Law ◽  
Diffusional Creep ◽  
Nanocrystalline Tio2 ◽  
Diffusion Limited ◽  
Sinter Forging ◽  
Boundary Sliding ◽  
Limited Process

ABSTRACTSinter-forging experiments were performed on cylindrical samples of n-TiO2 at various stresses and temperatures and with varying initial densities. The results are described on the basis of a constitutive law similar to creep deformation of dense bodies. The activation enthalpy measured is consisted with a grain boundary diffusion limited process, whereas the stress exponent found excludes simple diffusional creep. Furthermore, a threshold stress was found to exist. The results are discussed in terms of existing models and it is shown that the threshold stress can be explained in terms of the creation of additional surface area due to grain boundary sliding.

scholarly journals Denuded zones, diffusional creep, and grain boundary sliding

2002 ◽  
Vol 33 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Jeffrey Wadsworth ◽  
Oscar A. Ruano ◽  
Oleg D. Sherby
Keyword(s):  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Diffusional Creep ◽  
Boundary Sliding
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