Identification of the hardening law of materials with spherical indentation using the average representative strain for several penetration depths

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 606; pp. 409 - 416
• Main Authors: Moussa, Charbel, Hernot, Xavier, Bartier, Olivier, Delattre, Guillaume, Mauvoisin, Gérard
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 12.06.2014; Elsevier
• Subjects: Applied sciences; Average representative strain; Confidence domain; Cross-disciplinary physics: materials science; rheology; Deformation, plasticity, and creep; Elasticity. Plasticity; Engineering Sciences; Error analysis; Exact sciences and technology; Hardening; Hardening law; Hardness tests; Heterogeneity; Indentation; Law; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Penetration depth; Physics; Spherical indentation; Steel alloy; Strain; Treatment of materials and its effects on microstructure and properties; Hardening law; Spherical indentation; Confidence domain; Steel alloy; Average representative strain; Spherical shape; Displacement(deformation); Indentation; Penetration depth; Alloy steel; Hardening; Heterogeneity; Plasticity; Plastic properties; confidence domain; hardening law; spherical indentation; average representative strain
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2014.03.123

The identification of plastic properties with spherical indentation has been the subject of many studies in the last decades. In the present work, a new method for the determination of the hardening law of materials using the load–displacement curve of a spherical indentation test is proposed. This method is based on the use of an average representative strain. The advantage of the proposed average representative strain is that it is strictly obtained from the material in response to the indentation test. By using various values of penetration depth, the proposed method gives the range of strain for which the hardening law is precisely identified and allows determining a confidence domain that takes into account experimental imprecision and material heterogeneity. The influence of penetration depth and the error formula on the identified Hollomon hardening law are discussed in the present study. The present study clarifies many problems that were observed in previous studies such as the uniqueness of solution and the sensitivity of the indentation test to the plastic parameters of the Hollomon hardening law.