On the Specific Damaging Effects of Surface and Near-Surface Inclusions
The most significant results of an experimental study on the damaging effects of exogeneous ceramic inclusions in nickel-based superalloys are first reported. Attention is focused on some observations which conflict with a too-simple two-dimensional analysis of the problem. A more realistic theoretical treatment is then developed, which allows the calculation of configurational force and torque acting on a near-surface or surface inhomogeneity: the corresponding interfacial discontinuity of the elastostatic “energy—momentum” tensor is shown to be responsible for specific damaging effects of such inhomogeneities which could not be interpreted otherwise.
KeywordsFatigue Crack Tensile Axis Interfacial Cohesion Electron Beam Scanning Moire Pattern
Unable to display preview. Download preview PDF.
- Ambroise, M. H., Bretheau, T., and Zaoui, A. (1987a), Sur une notion de “torseur de configuration” caractérisant les interactions élastiques entre inclusion et matrice, C. R. Acad. Sci. Paris, 304, II, 245–250.Google Scholar
- Bretheau, T. and Caldemaison, D. (1981), Test of mechanical interaction models between polycrystal grains by local strain measurements. Proceedings of the 2nd Risø International Symposium on Metallurgy and Materials Science, pp. 157–161.Google Scholar
- Bretheau, T. and Caldemaison, D. (1983), Study of inclusion-matrix interaction by means of local strain measurements. Proceedings 4th Rise International Symposium on Metallurgy and Materials Science, pp. 173–178.Google Scholar
- Bretheau, T., Caldemaison, D., and Ambroise, M. H. (1988), Inclusion/matrix mechanical interaction: an in situ study by tensile and fatigue tests in the S.E.M. Proceedings ICSMA 8, Tampere, Finland, pp. 1051–1056.Google Scholar
- Bui, H. D. (1978), Mécanique de la rupture fragile, Masson, Paris.Google Scholar
- Germain, P. (1986), Mécanique, Ti, Ellipses, Ecole Polytechnique, Paris.Google Scholar
- Hauser, J. J. and Wells, M. G. H. (1970), Inclusions in high strength and bearing steels. Air Force Materials Laboratory Technical Report, 69–339.Google Scholar
- Lankford, J. (1977a), Effect of oxide inclusions on fatigue fracture, Int. Met. Rev., Sept., 221–228.Google Scholar
- Law, C. C. and Blackburn, M. J. (1980), Effects of ceramic inclusions on fatigue properties of a powder metallurgical nickel-base superalloy. Proceedings of the International Powder Metallurgy Conference and Exhibition, Washington, Vol. 12–14. Google Scholar
- Mura, T. (1982), Micromechanics of Defects in Solids, Martinus Nihoff, the Hague. Mura, T. and Furuhashi, R. (1984), The elastic inclusion with a sliding interface, J. Appl. Mech., 51, 308–310.Google Scholar
- Thompson, F. A., Cutler, C. P., and Siddall, R. J. (1979), The influence of inclusions on the low cycle fatigue properties of the nickel-based superalloy APK1 produced via the powder-route. Henry Wiggin and Co. Ltd., Technical Report 3184.Google Scholar