Effect of Firing Temperature and Time on Hybrid Fiber-Reinforced Shell for Investment Casting

Abstract

Glass fiber combined with aluminum silicate fiber was mixed into the slurry for preparing fiber-reinforced shell. The fired bending strength, the self-load deformation at elevated temperature and the permeability of hybrid fiber-reinforced shells were investigated. Combining with the fracture morphology of reinforced shell by SEM, the properties of hybrid fiber-reinforced shell were investigated. The results show that the fired bending strength of shell first increases and then decreases with variation of the firing temperature from 900 to 1000 °C and reaches the maximum of 4.12 MPa with firing temperature of 950 °C. Comparison of firing time, the maximum fired bending strength was obtained when firing time was 120 min. The self-loaded deformation at elevated temperature decreases with 0.5 wt% fiber addition. The permeability increases with fiber reinforcement. It is found by SEM that the bending load was borne by deformation and fracture of aluminum silicate fiber, and the glass fiber melt transformed into globular fiber due to the heat deformation at high temperatures which would decrease the strength.