Elevated temperature solid particle erosion of silicon carbide continuous fibre reinforced calcium aluminosilicate glass-ceramic matrix composite

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 to 726 degrees C. At room temperature, tests were conducted at two velocities. The lower (7 m s(-1)) did not generate lateral cracks and a wear rate of 0.004 mg g(-1) was observed. At the higher velocity (24 m s(-1)), lateral cracking was the main mechanism of material removal and an increased wear rate was found. The higher velocity wear rate of 0.16 mg g(-1) at room temperature increased to 0.26+/-0.02 mg g(-1) at all other temperatures. Increasing the temperature of the test leads to smoother wear surfaces exhibiting an increasing contribution from plasticity. The reasons for the increase in wear rate from room temperature to 400 degrees C are unclear. They are not 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. Above 400 degrees C the changes are broadly consistent with the replacement of carbon by silica at the fibre-matrix interface, release of residual stress and softening of the glass-ceramic matrix.