Failure Mechanisms of Nanostructured Gradient CrAlN Composite Coatings: A Simulation and Experimental Study

The nano-structured gradient CrAlN composite coatings were synthesized by plasma immersion ion implantation and deposition for surface modification of Mg-based alloy.The influence of a dynamic load on the microstructures and bearing capacity of the as-deposited CrAlN coatings was investigated with X-ray diffraction.energy dispersive spectroscopy.transmission electron microscopy and by simulation in finite element method.The results show that the high stress at the Al/AlN interface and severe elastic-plastic deformations of Al-layer.originated from the contact load.explained the failure mechanisms.For instance.when the contact-load induced interfacial stress was stronger than the yield limit of Al.the fatigue cracks.occurring on the Al-side near the Al/AlN interface.accounted for failure or breakdown of the CrAlN coatings.We suggest that the results be of some basic and technological interest in surface modification of Mg-based alloy.