Relationship Between Microstructures and Material Properties of Novel Fibrous Al2O3–(m-ZrO2)/t-ZrO2 Composites
Abstract:Novel fibrous Al2O3–(m-ZrO2)/t-ZrO2 (m, monoclinic; t, tetragonal) composites having a core/shell structure were fabricated by multi-extrusion, and their microstructures and material properties were investigated depending on the number of extrusions. The composites acquired a homogeneously fine fibrous structure as the number of extrusions increased. The bending strength and fracture toughness increased remarkably as the number of extrusions increased. In the fracture surface of the second passed composite, an Al2O3–(m-ZrO2) core region appeared, flat type, although some local regions existed with an intergranular fracture. However, the fracture mode of the t-ZrO2 region was of intergranular type having a sharp and rough surface. In the composite made by the fifth passed extrusion, the fracture strength and toughness values were high at about 665 MPa and 9.6 MPa·m1/2, respectively. The main fracture mode was a typical intergranular mode having a rough fracture surface, and the main multi-toughening was because of mechanisms such as crack bridging, microcracking, and phase transformation.
Document Type: Research Article
Affiliations: School of Advanced Materials Engineering, Engineering College, Kongju National University, Kongju City, Chungnam 314-701, Korea
Publication date: October 1, 2005