Load-Independent Hardness and Indentation Size Effect in Iron Aluminides

Sebastian Balos; Milan Pecanac; Mirjana Trivkovic; Savo Bojic; Pavel Hanus

doi:10.3390/ma17092107

Load-Independent Hardness and Indentation Size Effect in Iron Aluminides

Materials (Basel). 2024 Apr 29;17(9):2107. doi: 10.3390/ma17092107.

Authors

Sebastian Balos¹, Milan Pecanac¹, Mirjana Trivkovic¹, Savo Bojic¹, Pavel Hanus²

Affiliations

¹ Department of Production Engineering, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovica 6, 21000 Novi Sad, Serbia.
² Department of Material Science, Faculty of Mechanical Engineering, Technical University of Liberec, Studentská 1402/2, 461 17 Liberec, Czech Republic.

Abstract

In this paper, an iron-aluminide intermetallic compound with cerium addition was subjected to Vickers microhardness testing. A full range of Vickers microhardness loadings was applied: 10, 25, 50, 100, 200, 300, 500, and 1000 g. Tests were conducted in two areas: 0.5 mm under the surface of the rolled specimen and in the center. The aim was to find the optimal loading range that gives the true material microhardness, also deemed load-independent hardness, H_LIH. The results suggest that in the surface area, the reverse indentation size effect (RISE) occurred, similar to ceramics and brittle materials, while in the center, indentation size effect (ISE) behavior was obtained, more similar to metals. This clearly indicated an optimal microhardness of over 500 g in the surface region and over 100 g in the central region of the specimen. Load dependencies were quantitatively described by Meyer's law, proportional specimen resistance (PSR), and the modified PSR model. The modified PSR model proved to be the most adequate.

Keywords: intermetallic compounds; load-independent hardness; microhardness.

Grants and funding

This research has been supported by the Ministry of Science, Technological Development and Innovation (Contract No. 451-03-65/2024-03/200156) and the Faculty of Technical Sciences, University of Novi Sad through project “Scientific and Artistic Research Work of Researchers in Teaching and Associate Positions at the Faculty of Technical Sciences, University of Novi Sad” (No. 01-3394/1). The authors gratefully acknowledge the support from the Technical University of Liberec, Faculty of Mechanical Engineering, with the support of the Institutional Endowment for the Long-Term Conceptual Development of Research Institutes, as provided by the Ministry of Education, Youth, and Sports of the Czech Republic in the year 2024.