کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1660459 | 1008403 | 2009 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Study of fracture behaviour of bond coats on nickel superalloy by three-point bending of microbeams Study of fracture behaviour of bond coats on nickel superalloy by three-point bending of microbeams](/preview/png/1660459.png)
A microbeam testing geometry is designed to study the variation in fracture toughness across a compositionally graded NiAl coating on a superalloy substrate. A bi-material analytical model of fracture is used to evaluate toughness by deconvoluting load–displacement data generated in a three-point bending test. It is shown that the surface layers of a diffusion bond coat can be much more brittle than the interior despite the fact that elastic modulus and hardness do not display significant variations. Such a gradient in toughness allows stable crack propagation in a test that would normally lead to unstable fracture in a homogeneous, brittle material. As the crack approaches the interface, plasticity due to the presence of Ni3Al leads to gross bending and crack bifurcation.
Journal: Surface and Coatings Technology - Volume 204, Issue 5, 15 December 2009, Pages 586–592