An improved three-point bending method by nanoindentation

Hard thin coatings are used at both ambient and high temperatures to protect the underlying components from aggressive environments such as corrosion and wear. Commercial hard thin coatings, developed by physical vapour deposition, are typically of the order of 5 μm thick or less but, in order to estimate the stresses generated in the coating when the underlying component is stressed, either by monotonic or fatigue loading, it is essential to know the value of Young's modulus of both the substrate and the coating. The aim of this work is to modify a nanoindentation tester so that it can be used as a three-point bending test to measure the in-plane elastic modulus and also to compare the values with data measured by a standard nanoindenter using a Berkovich diamond.