Effects of frictional heat on the tribological properties of Ni3Al matrix self-lubricating composite containing graphene nanoplatelets under different loads

Abstract

In order to analyze the effects of frictional heat on the tribological performance of Ni3Al matrix self-lubricating composite containing 6.2 vol.% graphene nanoplatelets (NB), the dry sliding friction tests of Ni3Al-based alloy and NB against GCr15 steel ball are undertaken under different loads from 3 to 18 N. The effects of different amount of frictional heat on the friction and wear mechanism of NB are also studied. The results show that tribological performance of NB is better than that of Ni3Al-based alloy under same working conditions. The addition of graphene nanoplatelets promotes the formation of stable glaze layer on worn surface. In addition, graphene nanoplatelets enhance the thermal conductivity of NB, which makes the surface temperature of wear scar of NB in a proper range (about 413 ℃) at 13 N and avoids the serious friction and wear caused by the accumulation of frictional heat. At 13 N, NB shows the lower friction coefficient (0.32) and wear rate (3.6 × 10−5 mm3·N−1·m−1). It is attributed to the appropriate local temperature (about 413 ℃) of worn surface, resulting in the formation of stable glaze layer with good friction reducing and wear resistance on worn surface. This study was meaningful for optimizing applied loads to realize the appropriate frictional heat and good tribological behavior of NB.