TU-TESL

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According to foreign media reports, wine cups, missile heads, thermal barrier coatings on blades, auto parts, electronic and optical components and other objects are usually made of ceramics. Although the mechanical strength of ceramic is very high, if it is not exposed to high temperature and pulled slightly under load, it will break suddenly. But researchers at Purdue University in the US have developed a new process that allows ceramics to overcome their fragile properties, making them more resilient and durable. Purdue University calls this process "flash firing", that is, adding an electric field to the traditional sintering process to make parts made of ceramics in large quantities. Professor Haiyan Wang, School of engineering, Purdue University, said: "we have been able to prove that even at room temperature, ceramics sintered by electric field will undergo plastic deformation (elasticity) under high strain compression, which is very surprising." This study shows that the electric field applied in the formation of ceramics can make the materials deform very easily at room temperature, almost the same as that of metals. In particular, Purdue's team applied its technology to a widely used white pigment, titanium dioxide. "Previously, nanostructured twins were introduced into various metallic materials to improve their strength and ductility," said Jin Li, a postdoctoral researcher with the research team. However, few previous studies have shown that nano twins and stacking faults can greatly improve the plasticity of ceramics. " The remarkable improvement of the ductility of titanium dioxide at room temperature is due to the high density defects such as stacking fault, twin and dislocation during flash firing. The existence of such defects eliminates the need of ceramic defect nucleation, which usually requires a larger nucleation stress than the fracture stress. Li, the first author of this paper, said: "our research results are very important, opening a door for using a variety of different ceramics in a new way, which can make ceramics more flexible and durable, able to withstand heavy load and high temperature without being fragile." The increased plasticity of ceramics indicates that the mechanical durability of ceramics will be higher at relatively low temperature. Before the crack, the sample ceramics can bear the same compressive stress as some metals. "This kind of ductile ceramics can be used in many important applications, such as defense works, automobile manufacturing, nuclear reactors and sustainable energy equipment," said Xinghang Zhang, Professor of materials engineering and co director of the research group