2mm long short glass fibers were mixed into the slurries in order to improve the strength of silicon sol shell for investment casting process

and the green strength and fired strength of the silica sol shell specimens contained different glass fibers were investigated.Meanwhile

the fracture surface of short glass fiber-reinforced silicon sol shell specimens contained different contents of fibers was observed by SEM（scanning electron microscope）.The results show that the green strength of the shell specimens reinforced with glass fibers is improved remarkably.The shell reinforced with 0.6%glass fibers reaches the highest green strength of 2.991MPa

increased by approximately 15.75%compared with the unreinforced shell specimen.However

absence of obvious improvement of the strength of the short glass fiber-reinforced shell specimens fired at 900℃for 120min can be observed.It is also found by SEM（scanning electron microscope）that the short glass fibers in the reinforced silicon sol shell specimens are melted in part or in whole during the fired process

resulting in the decrease of the reinforced effects of glass fibers in the specimens.