ICME MODELING OF EROSION IN GAS-TURBINE GRADE CMC AND HVOF TEST

Erosion of gas turbine grade ceramic matrix composites (CMC) has recently attracted attention because it limits performance and component life in hot engines. This study developed physics of erosion failure evolution including delamination, cavity formation, and fiber loss using an integrated computational material engineering (ICME) approach. The erosion behavior of two CMC systems at two elevated temperatures (ET) under two high velocities is tested utilizing a high velocity oxygen fuel (HVOF). Two CMC erodent systems were selected, and experiments showed that erodent type and size affect erosion degradation which shows sensitivity to retained strength test after erosion. A computational Multi-Scale Progressive Failure Analysis (MS-PFA) predicted the erosion and post-erosion behavior of CMC's. Prediction of material degradation, micro-crack formation, interfacial degradation, and retained strength closely matched test observations. Method: A Multiphysics-based ICME methodology, and virtual design of experiment (DOE) software method includes: 1) Thermo-physics modeling of galvanic ash particles of layered ceramics predicting the mass transfer, 2) Micro-Mechanical Material model including layered CMC interphase and microcrack density, predicting progressive erosion evaluation and delamination, fracture toughness and hardness, and 3) Finite element explicit software predicting: a) Erosion rate as a function of impact angle under ambient temperature conditions; b) Effect of erodent concentration on erosion rate; c) Erosion rate as a function of velocity at 815 degrees C and 1200 degrees C under normal impact conditions; d) Variation of erosion rate with impingement angle and particle size, and velocity range; and e) Erosion rate as a function of erodent concentration, particle size, temperature and velocity under normal impact conditions.