Reciprocating Sliding Wear Behavior of 60NiTi As Compared to 440C Steel under Lubricated and Unlubricated Conditions

ABSTRACT

60NiTi is a hard (∼60 HRC) and highly corrosion-resistant intermetallic with a relatively low elastic modulus (∼100 GPa). In addition, this alloy exhibits a high compressive strength (∼2,500 MPa) and a high elastic compressive strain of over 5%. These attributes make this alloy an attractive candidate to be employed in structural and mechanical component applications. However, sliding wear behavior of this intermetallic has not yet been studied in a systematic way. In this study, lubricated and unlubricated reciprocating sliding wear behavior of 60NiTi is compared to 440 C steel as a conventional bearing and wear-resistant alloy. Results of experiments carried out under different loads show that 60NiTi, despite having a higher hardness, exhibits a significantly inferior wear behavior under dry conditions in comparison to 440 C steel. These unexpected results indicate that 60NiTi does not follow conventional wear theories where the wear of materials has an inverse relationship to their hardness. On the other hand, under lubricated conditions with castor oil and a synthetic gear oil, 60NiTi exhibits low specific wear rates. These results exhibit the importance of proper lubrication in sliding mode applications where 60NiTi is exploited as a wear-resistant alloy.

KEYWORDS:

• Nonferrous alloys
• unlubricated wear
• lubricants
• wear mechanisms
• abrasive wear
• fatigue

Acknowledgment

The authors thank Dr. Christopher DellaCorte, National Aeronautics and Space Administration (NASA), Glenn Research Center, Cleveland, Ohio, for his generous technical assistance and continuous support and for providing 60NiTi samples.