  The fracture characteristics of LuPO4 rare-earth phosphate environmental
barrier coating (EBC) material under molten calcium-magnesium aluminosilicate
(CMAS) corrosion is quantified. EBCs are crucial for protecting SiC-based
ceramic matrix composite components in the hot section of gas turbine engines.
Recent research has highlighted the potential of rare-earth phosphates as
better EBC materials than third-generation rare-earth silicates for CMAS
corrosion resistance. However, the fracture of EBCs under CMAS corrosion during
service remains a significant concern. This work investigates the fracture
behavior of LuPO4 using mesoscale simulation and experiments. The model uses
micrographs taken from fabricated EBC samples for mesoscale fracture
simulations. The simulation results are compared with experimental fracture
toughness data and validated using statistical tests (p<0.01). The simulation
results and experimental observations demonstrate that LuPO4 may exhibit higher
fracture resistance than Lu2SiO5 rare-earth silicate under similar CMAS
corrosion conditions, offering potential insights for future EBC design and
development.
