Anisotropic strength and fracture resistance of epoxy-ceramic composite materials produced by ultrasound freeze-casting

The anisotropic mechanical properties of ultrasound freeze cast epoxy-ceramic composite materials were studied by measuring flexural strength and fracture resistance curves (R-curves) using both unnotched notched three-point beam bending experiments, respectively, cut in three different orientations relative to the directional freezing axis. Three frequencies 0.699, 1.39 2.097 MHz used order introduce length scales into microstructure, with 0 as control samples. For all cases, composites showed higher when crack plane across direction ice growth (denoted YX orientation). more evident for material produced without (0 MHz) where was approximately 160% orientation compared two orthogonal orientations. Most increase found occur within a extension, ?a, ?0.5 mm. Comparing at ?a = 0.5 mm highly samples that 86% tougher than When operation applied, amount anisotropy gradually decreased operating frequency increased. high attributed alignment ceramic particles along front creating barrier propagation. Ultrasound modifies introducing relatively dense layers perpendicular act an additional, addition denser acts improve weaker reduce overall anisotropy.