The preparation and mechanical properties of the unidirectional carbon fiber reinforced zirconia composite

摘要

Unidirectional carbon fiber reinforced calcium stabilized zirconia composites (uni-C_f/ZrO_2) were prepared by slurry infiltration and hot-pressing method. The room temperature mechanical properties were investigated and the fracture features of composites were observed. A flexural strength of 588.0 MPa and fracture toughness of 15.4MPa centre dot m~(1/2) parallel to the fiber direction for the composite hot-pressed at 1500 deg C was attributed to the fiber pull-out. With increasing hot-pressing temperature from 1500 deg C to 1650 deg C, the relative density was augmented, but the mechanical properties of composites degraded gradually. Especially at 1650 deg C, the flexural strength and fracture toughness decreased significantly to 173.2 MPa and 5.0 MPa centre dot m~(1/2), respectively. Thermodynamic calculation and XRD, TEM investigations showed that carbon fibers reacted with ZrO_2 to form ZrC phase at 1650 deg C, and then formed chemical bonding and led to a strong interface between fiber and matrix, which resulted in the decrease of mechanical properties of the composite hot-pressed at higher temperatures. Moreover, the mechanical properties of carbon fibers degraded by the above reaction had also an adverse effect on the mechanical properties of the composite.