In order to improve the strength of silicon sol shell for investment casting process

glass fiber was mixed into the slurries to prepare the sol silicate shell samples.The properties such as bending strength of green shell

fired strength and self-loaded deformation at elevated temperature were investigated

and the fracture surface of shell samples were observed by SEM（scanning electron microscopy）.The results show that the green strength of shell specimens with glass fibers is increased

and the selfloaded deformation at elevated temperature is firstly increased and then decreased.The shell specimen reinforced with 0.6%fibers addition reaches the highest green strength of 4.61 MPa

and the self-loaded deformation at elevated temperature has a decrease of about 24% with the 1.0%fiber addition.The fired strength of shell sample with the concent of 0.2%

1

.0%glass fiber is increased more than 12%.It is found by SEM that the failure of the fiber-reinforced shell specimens at the applied load is attributed to breakdown of silicon sol films and pulling-out and debonding of fibers in the shell.