Publication Date


Document Type


First Advisor

Salehinia, Iman

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering


The scratching behavior of a Nb/NbC ceramic-metal (cermet) nanolaminate is studied to investigate the tribological properties using molecular dynamics. Many atomistic studies have reviewed the tribological properties of nanolaminates but are limited to only either metal-metal or ceramic-ceramic nanolaminates. This study aims to address how varying parameters such as metal-ceramic thickness ratio, indenter size, and scratching depth affect the tribological properties of cermet nanolaminate under a scratching load. Furthermore, the underlying deformation mechanisms are explored. To study the effect of the metal-ceramic ratio on Nb/NbC nanolaminate, molecular dynamics simulations are performed on different models varying the metal-ceramic ratio. The number of pile-up atoms, normal load, scratching load, and friction coefficients are calculated. Results show the scratching behaviors of Nb/NbC multilayers are significantly affected by the metal-ceramic thickness ratio at shallow penetration depth. The atomic pile-up (material removal) is larger for lower metal-ceramic thickness ratio, and the scratching load is lowest for larger metal-ceramic thickness ratios, resulting in a lower friction coefficient. But the metal-ceramic thickness ratios have less effect on the tribological properties of cermet when the indenter size is increased as a larger plastic volume is formed in each layer. However, the frictional properties show the opposite behavior at a deeper penetration depth. The highest frictional properties have been reported for a lower metal-ceramic ratio because of a significant increase in the normal load.


70 pages




Northern Illinois University

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