Abstract
Eshelby's continuum elastic model of the strain field of a coherent inclusion in an infinite matrix is adapted to describe the strain field associated with a circular plate of ellipsoidal cross-section transformed martensitically. Initially, the plate and the austenitic matrix are assumed to be elastically Isotropic, but with different moduli. The model is also used to calculate the strain field of a pair of parallel, ellipsoidal, martensite plates and of a single, isolated, square, flat plate. Finally, the treatment is extended to reveal the effects of elastic anisotropy. A criterion for thermoelastic growth of an isolated plate of martensite in terms of the permissible plastic yielding is proposed. Using the model of the strain fields, contours of the yield envelopes associated with an isolated plate of martensite formed in Fe 3Pt are calculated as a function of the atomic order in the parent, austenitic phase. It is concluded that thermoelastic growth is to be expected when the long-range order, S, is greater or equal to 0.2, in agreement with experimental observations. The equilibrium thickness of an isolated thermoelastic plate at M s and the associated chemical driving force are found to be much smaller than for plates formed irreversibly. Quantitatively, the predictions of the model applied to the ‘ordered’ alloy are in good agreement with experimental measurements. Clearly, Invar elastic softening is a major factor determining thermoelastic behavior in Fe 3Pt. In addition, the model is used to explore the reduction in elastic accommodation strain which can be achieved by the interactions of two or more plates arranged edge-to-edge or in stacks of self-accommodating plates. The influence of the shape of the individual plates is also discussed. Calculations using the anisotropic model for an isolated plate in the form of an oblate spheroid show that the effects of the large elastic anisotropy, which develops on cooling partially ordered Fe 3Pt, on the equilibrium thickness of the thermoelastic plate and the chemical driving force at M s are surprisingly small.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
