Study of the mechanical properties, strengthening and toughening mechanisms of Al2O3/TiC micro-nano-composite ceramic tool material

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 577; pp. 9 - 15
• Main Authors: Yin, Zengbin, Huang, Chuanzhen, Zou, Bin, Liu, Hanlian, Zhu, Hongtao, Wang, Jun
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 10-08-2013; Elsevier
• Subjects: Al2O3/TiC; Aluminum oxide; Applied sciences; Cobalt; Composite ceramics; Composite materials; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fracture toughness; Fractures; Grain boundaries; Hardness; Materials science; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Methods of nanofabrication; Microstructure; Nanomaterials; Nanostructure; Other materials; Particulate composites; Physics; Specific materials; Strengthening mechanisms; Titanium carbide; Toughening mechanisms; Al2O3/TiC; Mechanical properties; Composite ceramics; Toughening mechanisms; Microstructure; Strengthening mechanisms; Strengthening; Microcrack; Nanoparticle; Al; Crystal defect; Cobalt; Composite material; Grain boundary; O; TiC; Hardening; Stress effects; Rupture strength; Ceramic materials; Nanomaterial synthesis; Damaging; Stress concentration; Transgranular fracture; Interphase; Nanostructure; Hardness; Light emitting diode; Fracture toughness; Bending strength; Hot pressing; Tensile stress; Experimental result; Sintering; Crack
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2013.04.033

A type of Al2O3-based composite ceramic tool material simultaneously reinforced with micro-scale and nano-scale TiC particles was fabricated by the hot-pressing technology with different contents of cobalt additive. The experimental results showed that the Al2O3/TiC micro-nano-composite containing 3vol% Co, which was sintered under a pressure of 32MPa at 1650°C in vacuum for 20min, had optimal mechanical properties. Its flexural strength, fracture toughness and hardness were 916MPa, 8.3MPam1/2 and 18GPa, respectively. The relationships between the mechanical properties and microstructure were discussed. The mechanical properties of the composites increased and then decreased with the increase of the cobalt content. Low content of cobalt led to a poor relative density and excess cobalt caused micro-cracks at the grain boundaries, which decreased the mechanical properties of the composites. The existence of interphase cobalt could effectively decrease the stress concentration and the value of tensile stress in Al2O3 matrix. Both the micro-scale and nano-scale TiC particles contributed to the improvement of the flexural strength and fracture toughness of the composites. The intragranular nano-scale TiC particles influenced the ratio of grain boundary toughness to the grain toughness, leading to an appropriate percentage of transgranular fracture grains. The micro-scale TiC particles could not only enhance the ultimate damage stress of Al2O3 matrix, but also deflect and bridge the cracks.