New Algorithm to Determine the Yield Stress from FIMEC Test

Abstract:

The indentation test is one of the most common techniques for the mechanical characterization of materials. Different tests have been standardized, depending on punch geometry and indentation parameters, and different models have also been set up to predict indentation hardness and to estimate uni-axial mechanical properties for all the geometries (cone, wedge, pyramid, sphere, etc.). A flat-ended cylindrical indentation technique (FIMEC) has been developed by one of the present authors. FIMEC employs a cylindrical punch with diameter ranging from 3.0 to 0.5 mm and gives pressure-penetration curves from which yield stress and elasticity modulus can be determined. The specific characteristics of FIMEC are: 1-the high simplicity of the apparatus; 2-the possibility to get information about the local material properties on a scale large enough to include many grains (data represent bulk characteristics and are not influenced by those factors which dramatically affect micro-and nanoindentation tests); 3-the large versatility in industrial applications such as the control of welding quality, 4-the on-line monitoring of forging or extrusion processes etc.. This paper describes a new algorithm developed to calculate the yield stress from FIMEC curves. To assess the reliability of the method, it has been tested on several metals of known characteristics and the scattering of data with respect those from tensile tests resulted to be within ±7%.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 2272-2277
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.2272
• Online since: May 2014
• Authors: Laura Ciambella*, Roberto Montanari
• Keywords: Algorithm (GA), FIMEC, Indentation Test, Yield Stress

References

[1] P. Gondi, R. Montanari, A. Sili, J. of Nuclear Materials, 212-215 (1994) 1688.

[2] P. Gondi, A. Donato, R. Montanari, A. Sili, J. of Nuclear Materials 233-237 (1996) 1557.

[3] A. Donato, P. Gondi, R. Montanari, F. Moreschi, A. Sili, S. Storai, J. of Nuclear Materials 258-263 (1998) 446.

DOI: 10.1016/s0022-3115(98)00428-0

[4] S. Missori, R. Montanari, A. Sili, La Metallurgia Italiana 3 (2001) 35.

[5] G. Filacchioni, R. Montanari, M. E. Tata, L. Pilloni, J. of Nuclear Materials 307-311 (2002) 1563.

[6] G. Costanza, R. Montanari, F. Quadrini, M.E. Tata, Proc. 5th Int. Conf. THE COATINGS, Kassandra October 2005, p.345.

[7] G. Costanza, R. Montanari, M.E. Tata, La Metallurgia Italiana 5 (2006) 27.

[8] B. Iacovone, S. Libardi, A. Molinari, R. Montanari, P. Plini, J. of Testing and Evaluation, (2008) 36.

[9] I. Cappelloni, P. Deodati, R. Montanari, A. Moriani. Adv. Mater. Res. Vol. 89-91 (2010), 751.

DOI: 10.4028/www.scientific.net/amr.89-91.751

[10] K.L. Johnson, Contact Mechanics, Cambridge University Press (1985) 153-201.

[11] B. Riccardi, R. Montanari, Materials Science and Engineering A, 381/1-2 (2004) 281.

[12] H.Y. Yu, M.A. Imam, B.B. Rath, J. of Mater. Science 20 (1985) 636.

[13] R.T. Shield, Proc. of Royal Society A233 (1955) 267.

[14] G. Eason, R.T. Shield, Zeitschrift für Angewandte Mathematik und Physik 11 (1960) 33.

[15] C. Cristalli, S. Storai, N. Bettocchi, poster at DERIVIN summer school-MATTER Project.

[16] L.O. Schafer, H. Kempe, MANET-II- Primärbericht, p.11.

[17] F. Tavassoli, DEMO Interim Structural Design Criteria, Appendix A Material Design Limit Data, A3. S18F IEA F82H Steel, p.18.

[18] F. Tavassoli, DEMO Interim Structural Design Criteria, Appendix A Material Design Limit Data, A3. S18E Eurofer Steel, p.19.

[19] G. Filacchioni, Private report.

[20] B.W. Christ, Effect of Specimen Preparation, Setup and Test Procedures on Test Results, Metals Handbook, 9th ed., Vol 8, 32.