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Unstable Spreading of a Fluid Inclusion in a Grrain Boundary under Normal Stress
Author(s) -
RAJ RISHI
Publication year - 1986
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1986.tb07476.x
Subject(s) - dihedral angle , materials science , isotropy , inclusion (mineral) , stress (linguistics) , surface energy , mechanics , grain boundary , work (physics) , radius , curvature , thermodynamics , composite material , geometry , chemistry , optics , physics , mathematics , microstructure , hydrogen bond , linguistics , philosophy , organic chemistry , computer security , molecule , computer science
A fluid inclusion trapped in a stress‐free grain boundary will assume an equilibrium lenslike shape. The dihedral angle at apex will be determined by the ratio of the (isotropic) solid‐solid and solid‐liquid interface energies. The radius of curvature of the lens surface will depend on the volume of the inclusion. If a normal stress is now applied across the interface, then the mechanical energy (equal to the sum of the external work and (he strain energy) and the interface energy will together determine the shape of the inclusion. In this paper it is shown that the inclusion can spread catastrophically if the applied stress is greater than a critical value. The magnitude of the critical stress depends on the equilibrium dihedral angle and the volume of the inclusion. A smaller angle and a larger volume lead to a smaller value of the critical stress. As an example a fluid inclusion which is ∼1 μm in size and forms a dihedral angle of 15° is unstable under an applied stress of 100 MPa. The results have slgniflciincc in the phenomenon of liquid‐phase‐enlianccd sintering and diffuslonal creep.