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

Nanoindentation test and fretting wear experiments were conducted to investigate the connection between the hardness anomalies, elastic modulus, plastic 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 curves from nanoindentation load-displacement test was defined as plastic deformation work and used to assess the resistance to plastic deformation of multilayers. TiN/CrN multilayers showed the hardness anomaly at Lambda=15-21 nm. The coefficient of friction of TiN/CrN multilayers against bearing ball 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 hardness 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 smaller than the calculated values because of the transformation of the wear regime from mixed stick-slip to gross slip for the TiN/CrN multilayers. (C) 1999 Published by Elsevier Science S.A, All rights reserved.