Significant research has been conducted in recent years on the �-based titanium aluminide alloys. The low density of �-TiAl relative to current nickel-based superalloys, has made it an attractive candidate for use in the low-pressure turbine blades of gas turbine engines [1]. In addition to weight savings, the lower density leads to higher specific stiffness and good high temperature strength r...

In flip-chip package, the mismatch of thermal expansion coefficients between the silicon die and packaging substrate induces concentrated stress field around the edges and corners of silicon die during assembly, testing and services. The concentrated stresses result in delamination on many interfaces on several levels of structures, in various length scales from tens of nanometers to hundreds o...

A study is made of the crack resistance of multilaminates consisting of brittle layers interleaved with compliant interlayers and bonded to compliant substrates. Specific attention is paid to flexure-generated radial cracks in the undersurfaces of individual glass layers from concentrated loads applied at the top surfaces. A proposed condition for acceptance of such multilayer systems is that r...

The multiscale nature of cracking in ferroelectric ceramics is explored in relation to the crack growth enhancement and retardation behavior when the direction of applied electric ®eld is reversed with reference to that of poling. An a priori knowledge of the prevailing fracture behavior is invoked for the energy dissipated in exchange of the macroand micro-crack surface. To avoid the formalism...

Despite decades of study, the atomic-scale mechanisms of fatigue crack growth remain elusive. Here we use the coupled atomistic–discrete dislocation method, a multiscale simulation method, to examine the influence of dislocation glide resistance on near-threshold fatigue crack growth in an aluminum alloy. The simulations indicate that the threshold increases with an increase in dislocation glid...

Crack detection is one of the important tasks for industrial materials and products from the standpoint of safety. The assessment of the crack geometry would be a crucial parameter for quality control of products. The crack width and length could be rather easily identified by inspecting the actual surface picture. However, the depth of small crack would be difficult to estimate non-destructive...

Serial mechanical sectioning and high resolution X-ray tomography have been used to study the three-dimensional morphology of small fatigue cracks growing in a 12 Cr tempered martensitic steam turbine blade material. A range of surface conditions has been studied, namely polished and shot peened (with varying levels of intensity). In the polished (unpeened) condition, inclusions (alumina and ma...