On the measurement and interpretation of residual stress at the micro-scale

In the present paper we consider two representative methods for residual stress evaluation at the micro-scale: a (semi-)destructive method involving material removal and the measurement of strain relief; and a non-destructive X-ray diffraction technique involving the use of micro-focused synchrotron...

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Bibliographic Details
Main Authors: Korsunsky, A, Bemporad, E, Sebastiani, M, Hofmann, F, Dave, S
Format: Journal article
Language:English
Published: World Scientific Publishing Company 2010
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Summary:In the present paper we consider two representative methods for residual stress evaluation at the micro-scale: a (semi-)destructive method involving material removal and the measurement of strain relief; and a non-destructive X-ray diffraction technique involving the use of micro-focused synchrotron X-ray beam. A recently developed strain relief approach is described using a Focused Ion Beam (FIB) to create a circular trench of progressively increasing depth around a circular "island". Residual stress is evaluated by the comparison of the strain relief (measured by digital correlation of displacements or strains) with Finite Element simulations. The technique is illustrated for a thin TiN coating layer. The second approach uses focused synchrotron X-ray beams for white beam Laue diffraction. Demonstration experiments described involve in situ loading of commercially pure nickel foil. Procedures for validation and improvement of accuracy are discussed.