Influence of microstructure and chemistry on the fracture toughness of dental ceramics
Influence of microstructure and chemistry on the fracture toughness of dental ceramics
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DOI：
10.1016/s0109-5641(03)00002-2
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发表时间：
2003-11-01
期刊：
影响因子：
5
通讯作者：
Lloyd, IK
中科院分区：
文献类型：
--
作者：
Quinn, JB;Sundar, V;Lloyd, IK
目标。本研究的主要目的是测量几组牙科陶瓷的断裂韧性，并确定化学和微观结构如何影响该特性。方法。使用单边预裂梁 (SEPB) 和单边 V 形缺口梁 (SEVNB) 方法获得断裂韧性 (K,,) 值。本研究中的三组材料还获得了动态杨氏模量，该模量通常与强度成正比，并已用于在理论基础上解释微观结构/韧性关系。第一组由云母玻璃陶瓷组成，包括微观结构发生系统变化但化学性质没有变化的模型材料。第二组是长石瓷，其微观结构变化很大，但化学成分变化不大。第三组陶瓷在化学成分和微观结构上都有显着差异。结果。与基础玻璃相比，云母微晶玻璃和长石瓷的韧性上限显着提高，但仍低于2 MPa·m(1/2)。最高的韧性与高结晶度、大晶粒和高长径比相关。第三组 K-1c 值对于二硅酸锂玻璃陶瓷为 2.8 MPa m(1/2)，对于玻璃注入氧化铝为 3.1 MPa m(1/2)，对于氧化锆为 4.9 MPa m(1/2)。微观结构特征和测量性能之间的相关性支持文献中的理论预测。从实践的角度来看，微观结构效应被发现很重要，但只在有限的范围内；化学显然定义了一系列可实现的性能值。这表明仅通过微观结构的变化不可能实现断裂韧性的大幅提高。为云母玻璃陶瓷确定的函数关系可以根据微观结构定量预测断裂韧性。 (C) 2003 年牙科材料学会。由爱思唯尔有限公司出版。保留所有权利。
Objectives. the primary aim of this research was to measure fracture toughness for several groups of dental ceramics, and determine how this property is affected by chemistry and microstructure.Methods. Fracture toughness (K,,) values were obtained using Single Edge Precracked Beam (SEPB) and Single Edge V-Notch Beam (SEVNB) methods. Dynamic Young's modulus, which often scales with strength and has been used in explaining the microstructure/toughness relationship on a theoretical basis, was also obtained for the three groups of materials comprising this study. The first group, consisting of micaceous glass ceramics, included model materials that varied systematically in microstructure but not in chemistry. The second group, the feldspathic porcelains, varied significantly in microstructure, but little in chemistry. The ceramics comprising the third group were significantly different in both chemistry and microstructure.Results. Upper toughness limits for the micaceous glass-ceramics and feldspathic porcelains were significantly raised compared to the base glasses, but remained under 2 MPa m(1/2). The highest toughnesses were associated with high percent crystallinity, large grains and high aspect ratios. The third group K-1c values were 2.8 MPa m(1/2) for a lithium disilicate glass-ceramic, 3.1 MPa m(1/2) for a glass-infused alumina, and 4.9 MPa m(1/2) for zirconia.Significance. the correlations between microstructural characteristics and measured properties supports theoretical predictions in the literature. From a practical standpoint, microstructural effects were found to be important, but only within a limited range; the chemistry apparently defined a band of achievable property values. This suggests very large increases in fracture toughness are unlikely to be attained by changes in microstructure alone. A functional relationship determined for the micaceous glass-ceramics enables quantitative predictions of fracture toughness based on the microstructure. (C) 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.