Continuous measurements of load-penetration curves with spherical micro-indenters and the estimation of mechanical properties
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139 (United States)
Elastic and plastic properties of metals and Young{close_quote}s modulus of ceramics are determined in the microindentation regime by continuous measurements of load versus depth of penetration with {ital spherical} indenters. Calibration procedures, usually applied in nanoindentation experiments, are not needed in the microregime where spherical indenters (rather than sharp indenters with microscopical spherical tips) can be manufactured. As indenters of larger diameters are used, the elastic response of the specimen can be probed during the loading stage of the indentation tests (and not only during unloading, as is the case with nanoindenters). Hence, an accurate determination of the Young{close_quote}s modulus can be achieved without a prior knowledge of possible {open_quotes}piling up{close_quotes} or {open_quotes}sinking in{close_quotes} which may occur at the perimeter of the contact area. The contact response of materials is shown to undergo four distinct regions: (i) pre-Hertzian regime, (ii) Hertzian regime, (iii) small-scale plasticity, and (iv) large-scale plasticity. A general methodology for estimation of yield strength and hardening exponent of metals is proposed in the last regime. {copyright} {ital 1998 Materials Research Society.}
- OSTI ID:
- 624856
- Journal Information:
- Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 5 Vol. 13; ISSN JMREEE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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