Hardness anomaly, plastic deformation work and fretting wear properties ofpolycrystalline TiN/CrN multilayers

Nanoindentation test and fretting wear experiments were conducted to invest igate the connection between the hardness anomalies, elastic modulus, plast ic deformation work and fretting wear behavior of TiN/CrN multilayers with different modulation period Lambda deposited on WC/Co cemented substrate by reactive magnetron sputtering. The area formed by loading and unloading cu rves from nanoindentation load-displacement test was defined as plastic def ormation work and used to assess the resistance to plastic deformation of m ultilayers. TiN/CrN multilayers showed the hardness anomaly at Lambda=15-21 nm. The coefficient of friction of TiN/CrN multilayers against bearing bal l ranged from 0.15 to 0.25, and CrN and TiN is 0.12 and 0.30, respectively. The wear volume of multilayers indicated an inverse relation with the hard ness anomaly and plastic deformation resistance. The measured Hertz contact diameter also correlates to the equivalent elastic modulus of bearing ball and TiN/CrN multilayers, however, the measured contact diameters were smal ler than the calculated values because of the transformation of the wear re gime from mixed stick-slip to gross slip for the TiN/CrN multilayers. (C) 1 999 Published by Elsevier Science S.A, All rights reserved.