Fracture tests of microsized TiAl specimens
Fracture tests of microsized TiAl specimens
复制标题
DOI：
10.1111/j.1460-2695.2005.00893.x
复制
发表时间：
2005-08-01
影响因子：
3.7
通讯作者：
Bowen, P
中科院分区：
文献类型：
--
作者：
Halford, TP;Takashima, K;Bowen, P
γ-TiAl基材料具有在高达700 ℃的温度下提供上级的蠕变强度、高屈服强度和杨氏模量的能力。这导致了对γ-TiAl基材料用于旨在用于高温下的应用的微机电系统（MEMS）的考虑。考虑用于这些应用的一种γ-TiAl基材料是称为合金7/Ti-46 Al-5 Nb-1 W（at%）的组合物。在这种情况下，该材料以具有全层状结构和菌落尺寸约为75 μ m的锻态形式进行测试。研究了这种材料的加载体积小于传统样品的影响。这是为了提高对断裂韧性行为的理解，这最终将需要这种材料的部件具有横截面; 18 × 6 μ m。在这里，我们专注于一个专门开发的机器，它提供了精确的加载微型悬臂梁通过金刚石尖端。这种材料的断裂韧性性能的定向性质被认为是在有关的局部取向的层状微观结构和由此产生的故障模式发生。
gamma-TiAl-based materials have the ability to provide superior creep strength, high yield strength and Young's modulus at temperatures as high as 700 degrees C. This has led to the consideration of gamma-TiAl-based materials for use in microelectromechanical systems (MEMS) intended for application at elevated temperatures. One gamma-TiAl-based material under consideration for these applications is the composition known as Alloy 7/Ti-46Al-5Nb-1W (at%). In this case, this material is tested in the as-wrought form with a fully lamellar structure and a colony size approximate to 75 mu m. The effect of loading volumes of this material smaller than conventional samples is investigated. This is carried out in order to improve understanding of the fracture toughness behaviour, which ultimately will be required of components of this material with a cross-section; 18 x 6 mu m. Here, we focus upon a specially developed machine, which provides accurate loading of microsized cantilever beams through a diamond tip. The directional nature of the fracture toughness properties of this material is considered in relation to the local orientation of the lamellar microstructure and the resulting failure modes occurring.