Effect of temperature on wear mechanisms of an aluminium - based abradable coating for aircraft engines after a dynamic interaction with a Ti6Al4V blade

Abstract

Small blade-casing clearances in aircraft engines reduce fuel consumption but increase the risks of contact interactions due to working conditions. These interactions cannot be avoided but their effects can be reduced by using abradable linings thermally sprayed inside the casings. To investigate these interactions and the mechanisms of wear deriving from them, a specific ballistic bench has been developed in order to perform representative tests of the low-pressure compressor environment (up to 270 °C) and enabling only one interaction between an aluminum-based abradable sample and a Ti6Al4V tool. Contact forces and incursion depth were measured for a nominal depth of cut of 100 μm and at a mean velocity of 125 m/s. It has been shown that the temperature affects mainly the abradable behaviour under these high-speed interactions. In addition, the wear that is resulting at high temperature is driven by a process that can be very different from the low temperature case.