Spherical indentation of compositionally graded materials: Theory and experiments
- Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering
Computational and experimental results on the evolution of stresses and deformation fields due to indentation from a rigid spherical indenter on a graded substrate are presented. The analyses address the variations in Young`s modulus, E, of the substrate as a function of depth, z, beneath the indented surface for an exponential law, E = E{sub 0}e{sup {alpha}z}, where E{sub 0} is Young`s modulus at the surface and 1/{alpha} is a length parameter. The finite element simulations are used to check the analytical theory of Giannakopoulos and Suresh, and are used to gain further insights into the effects of the variation in Poisson ratio, v, with depth. The theoretically predicted force-indenter penetration (P-h) curves are also compared with direct experimental measurements made on compositionally graded Ni-Al{sub 2}O{sub 3} and TiAl-Y{sub 2}O{sub 3}-stabilized TZP composites of known composition gradients. A new method is proposed for the estimation of Young`s modulus variations through a compositionally graded layer by recourse to spherical indentation.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Massachusetts Inst. of Tech., Cambridge, MA (United States)
- DOE Contract Number:
- FG02-93ER45506
- OSTI ID:
- 474170
- Journal Information:
- Acta Materialia, Vol. 45, Issue 4; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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