Effect of temperature and particle velocity on the erosion of a silicon carbide continuous fibre reinforced calcium aluminosilicate glass-ceramic matrix composite

摘要

A unidirectional silicon carbide continuous fibre reinforced calcium aluminosilicate (CAS/SiC) glass-ceramic matrix composite has been subjected to silica sand solid particle erosion over the temperature range 20-726℃. Initial tests were conducted with a constant mass flow rate of gas of 401 mm{sup}(-1). This gave a wear rate of 0.16 mg g{sup}(-1) at room temperature which increased to 0.26±0.02 mg g{sup}(-1) at 400℃ and above. When the increase in gas velocity, and hence particle velocity, was taken into account the wear rate was predicted to decrease with increasing temperature for a constant particle velocity. A wear rate of 0.06 mg g{sup}(-1) was measured at 300℃, which showed excellent agreement with the prediction of 0.07 mg g{sup}(-1). As the main mechanism of material removal is via lateral cracking, this decrease in wear rate is broadly consistent with the release of residual axial tensile stresses in the matrix resulting from mismatches in the coefficients of thermal expansion of the two phases on cooling down from the processing temperature.