Friction and wear behavior of Cu-4 wt.％Ni-TiC composites under dry sliding conditions

The present study synthesized Cu-4 wt％ Ni matrix composites reinforced with different percentages of TiC (0,2,4,6,and 8 wt％) through high-energy ball milling,followed by compaction and sintering.The friction and wear behavior was examined at four different normal loads of 5,10,15,and 20 N.A constant sliding speed of 1.25 m/s was maintained while sliding against a hardened counterface made of EN31 steel (HRC 60) under ambient conditions using a pin-on-disk test rig.The composite hardness increased until the addition of 4 wt％ of TiC,beyond which it was observed to decrease.Such a trend may be attributed to the TiC agglomeration in the composites containing relatively larger amounts of TiC (i.e.,6 and 8 wt％).The wear rate linearly increased with the load.However,the composites exhibited a lower rate of wear than the matrix alloy,which may have resulted from the relatively higher hardness of composites.The observed friction and wear behavior has been explained on the basis of hardness and presence of the transfer layer on the worn surface and its nature,i.e.,loose or well compacted.Addition of 4 wt％ TiC showed the optimum performance in terms of friction and wear caused by its higher hardness and ability to hold a transfer layer of a relatively larger thickness compared to the other materials.The wear mechanism for the Cu4Ni matrix alloy was a mix of adhesive and oxidative wear and primarily abrasive for the composites containing hard TiC particles.

Dry Sliding Wear Behavior of Silver Containing Ni-Based Composite-Steel Tribo-Pair

Ni-based self lubricating composites containing four different amounts of silver were prepared by powder metallurgy(PM) route.The room temperature friction and wear behavior was investigated by carrying out dry sliding experiments against bearing steel using a ring-on-disk configuration.Tests were conducted at a constant load of 100 N and different sliding speeds of 0.5,1.0 and 1.5 m/s to analyze the effect of both the speed and the silver content on the wear behavior of the tribo-pair.The friction coefficient and the wear rate of the composites were found to decrease with increasing both the sliding speed and the silver content.The wear rate of the counterface was observed to be a little higher when it was siding against the composite having silver in comparison to that without any silver.However,the overall wear rate of the tribo-pair was found to decrease with increasing sliding speed and silver content.