Elevated temperature performance: Arc-jet testing of carbon fiber reinforced ZrB <sub>2</sub> bars up to 2200 °C for strength retention assessment
Diletta Sciti, Antonio Vinci, Luca Zoli, Pietro Galizia, Marat Mor, William G. Fahrenholtz, Stefano Mungiguerra, Raffaele Savino, Antonio Maria Caporale, A. Airoldi
Abstract
For the first time, ultra-high temperature ceramic matrix composite bars were tested inside an arc-jet facility to investigate the impact of oxidation damage on strength retention. The composite bars, which were based on a ZrB<sub>2</sub>/SiC matrix reinforced with 45 vol% carbon fibers, were produced by slurry impregnation and sintering. The first batch was tested under 3-point (pt) bending, and two additional batches were exposed to plasma of dissociated air up to a temperature of 2200 °C for 2 min or 2.2 min and then subjected to 3-pt bending. More than 75% of the initial strength was retained even after repeated testing, demonstrating the durability and reusability of the material. Volatility diagrams were calculated to explain the oxide layering observed, while a numerical model was developed to correlate the experimental mechanical data with the elastic properties. The decrease of strength was attributed to a reduction of the cross section due to oxidation.