Mechanical properties and strengthening mechanism of SiC particle reinforced porcelain

Abstract

AbstractMechanical properties of porcelain based on feldspar porcelain as a matrix with SiC particles as a reinforcing phase were studied in terms of the effects of SiC content, firing temperature, and holding time. A maximum flexural strength of 122 ± 4 MPa was achieved for a sample with 8 wt% SiC content treated at 1260°C for 30 min, which is 90.6% as high as than that of the unmodified matrix (64 ± 5 MPa). The fracture toughness and elastic modulus of the former sample were 1.71 MPa · m1/2 and 89.975 GPa, respectively. Because the thermal expansion coefficient of SiC (4.40 × 10−6/°C) is smaller than that of the glass phase (6.60 × 10−6/°C), the SiC particles remain in a state of compressive stress after the porcelain cooling. This characteristic restricts crack growth and offsets the tensile stress of the glass phase, restraining crystal growth owing to the tensile stress pinning the grains, such that the mechanical properties are improved.