Fracture Morphology and Fiber Reinforcement Mechanism of Composite Shells with Different Interfaces.

Recently, significant progress has been made in the preparation and properties of fiber-reinforced shells for investment casting; however, the research on the enhancement mechanism of fiber is inadequate. Herein, the composite shell is prepared using the airflow placement fiber process, and the conventional method, preimmersion silica sol and preimmersion slurry methods are adopted to obtain different interfaces between the matrix and fibers. Combined with the directional tensile test and fracture morphology of the shell observed via scanning electron microscope and stereomicroscope, the fiber-reinforced mechanism of the shell is analyzed in detail. It is found that the shell with polypropylene fibers is strengthened by the fiber pull-out, debonding, debonding-deformation and bridging-deformation, even with the different interface bonding between the matrix and fibers. However, the main failure modes of fibers are different under different interface conditions. The fibers in the preimmersion slurry shell mainly fail in the form of debonding-deformation and bridging-deformation, which makes the green strength of composite shells increase significantly. [ABSTRACT FROM AUTHOR]