ORIGINAL PAPER Dry Sliding Tribological Properties of Fe-Based Bulk Metallic Glass Dawit Zenebe Segu • Jae Hyouk Choi • Seonghoon Yi • Seock Sam Kim Received: 26 December 2011 / Accepted: 16 April 2012 / Published online: 28 April 2012 Ó Springer Science+Business Media, LLC 2012 Abstract The dry or unlubricated sliding friction and wear properties of as-cast and annealed BMG (bulk metallic glass) with nominal composition of Fe 66.7 C 7.0- Si 3.3 B 5.5 P 8.7 Cr 2.3 Al 2.0 Mo 4.5 against Si 3 N 4 ceramic ball was studied, along with a conventional material, using a ball- on-disk tribotester at room temperature. The overall aver- age coefficient of friction value of the as-cast BMG was in the range of 0.26–0.42, which was better than the con- ventional material SUJ2 (0.36–0.46) and comparable with SUS304 (0.31–0.40). The wear mechanism of the Fe-based BMG changed with wear condition. The wear rate increased with increasing load. The hardness of the BMG increased during annealing, however, the wear resistance did not increase proportionally. Keywords Fe-based bulk metallic glass (BMG) Á Tribological properties Á Wear resistance 1 Introduction As a new category of metallic materials, metallic glasses are characterized by a combination of their disordered structures and interatomic metallic bonds. This amorphous (or disordered) structure of metallic glasses gives them many unique properties compared to crystalline materials, such as higher hardness and strength, resistance to gamma radiation damage, higher resistance to corrosion, and better magnetic properties. These make them an attractive mate- rial for various technological applications [1]. The promising attribute of metallic glasses have led to form new alloy compositions, which can be produced by conventional casting techniques with thicknesses up to several centimeters that are labeled as ‘‘Bulk Metallic Glasses’’ (BMGs). The BMGs received considerable attention because of their unique properties that are superior to their crystalline counterparts, and with further development; this class of alloys can lead to applications as structural and functional materials [2]. Previous studies have shown that the wear behavior of BMGs does not follow the empirical Archard’s wear equation, which indicates a positive increase of wear resistance with hardness [3]. Furthermore, there are con- tradictory data in the literature regarding the wear perfor- mance of BMGs, in which some reports have indicated a superior wear resistance of BMGs than their crystallized states while others showed an inferior wear resistance of BMGs [4]. It was suggested that these discrepancies may arise due to the fact that BMGs are in a non-equilibrium state, and a slight variation in test conditions and local chemical compositions will change microstructures and results in different wear behaviors [3]. Among BMGs, Fe-based systems exhibit high strength and good corrosion, wear resistance and magnetic properties, coupled with relatively low materials cost [2, 5], which make them an important alloys for research. Especially, due to their hardness, they are considered to be a potential candidate for wear application. D. Z. Segu Á S. S. Kim (&) Department of Mechanical Engineering, Graduate School, Kyungpook National University, Daegu 702-701, Korea e-mail: sskim@knu.ac.kr J. H. Choi School of Architecture, Chosun University, Gwangju 501-759, Korea S. Yi Department of Material Science and Metallurgy, Kyungpook National University, Daegu 702-701, Korea 123 Tribol Lett (2012) 47:131–138 DOI 10.1007/s11249-012-9969-9