Dry sliding tribological behavior of nanocrystalline and conventional polycrystalline copper

Abstract

Dry sliding tribological behavior of an electro-deposited nanocrystalline Cu (nc Cu) and a conventional coarse-grained Cu (cg Cu) has been investigated using a ball-on-disc tribometer with cemented tungsten carbide ball as the counterface. Experimental results showed that the wear resistance of copper with the nanocrystalline microstructure was enhanced relative to the coarsegrained form. The steady-state friction coefficient of the nc Cu was obviously lower than that of the cg Cu when the load is below 20 N. The wear volume of the nc Cu was always lower than that of the cg Cu for the applied load range from 5 to 40 N. With increase of the load, the difference in wear resistance between the nc and the cg Cu decreased. The enhancement of the wear properties of the nc Cu was associated with the high hardness and the low work-hardening rate of the nanocrystalline structure, and easily being oxidized of wear debris, which was attributed to grain refinement.

Investigation of the friction layer of Ni 3 Al matrix composites

“…3b). Although many experimental studies [24,25] have confirmed the formation of ultra-refine or NC structure in the worn surfaces of ductile materials, obvious grain boundaries of large Ni 3 Al particles are not observed after wear test at 2 N in this study, indicating that grain refinement or nanocrystallization is not likely to occur on the worn surface after a sufficiently long period of dry sliding operation (960 m). However, it should be emphasized that a wearinduced layer is clearly observable at the top of the worn surface.…”

Comparison of the wear and frictional properties of Cu matrix composites prepared by pulsed electric current sintering

“…Oxidational wear is the most common chemical wear process [3,6], in which a thin oxide layer prevents the bonding between the asperities as well as metal-metal contact. The oxide can be a result of diffusion controlled oxide growth or agglomeration of oxide/oxidized debris/inclusion of oxide/oxygen into highly disrupted surface regions [11,12]. After critical thickness, it can lead to delamination at the metal/oxide interface [11][12][13].…”

“…For Cu, the attemps to reduce wear and the friction force includes grain refinement [12][13][14][15], presence of oxide film/depris, tribolayer or mechanically mixed layer (MML) [5,[12][13][14][16][17][18][19][20], as well as alloying, and DS [4,5,[19][20][21][22][23]. The tribological behaviour of nano-and coarse-grained Cu has been studied in [12][13][14][15]. It was shown that in ballon-disk oscillating tests with 5 N load against WC-Co balls the wear loss was four times higher for c-Cu (coarse-Cu) than for nc-Cu (nano-Cu), the respective CoFs being 0.74 and 0.54.…”

Fretting wear behavior of nanocrystalline surface layer of pure copper under oil lubrication

“…During the last decade, tribological properties of nanostructured materials have been paid more attention and many experimental results have shown a significant enhancement in friction and wear properties of nanostructured materials, e.g. [1][2][3][4][5]. However, it should be mentioned that most investigations on wear properties of nanostructured materials have been focused on sliding wear mode.…”