The fracture behavior of a high-strength low-alloy steel subjected to tempforming at 873 K, 923 or 973 K was studied by means impact and bending tests. A decrease in temperature promoted the grain refinement resulting ultrafine grained lamellar-type microstructure with finely dispersed particles that led significant strengthening along an increase toughness. tempformed samples exhibited Charpy ...

The mode I energy release rate, including the effect of residual stresses, was evaluated for both adhesive and laminate double cantilever beam specimens. The energy release rate can be partitioned into a mechanical term and a residual stress term in beam theory. The beamtheory mechanical term is not very accurate, but can be corrected by a slight modification to a previous correction factor. Th...

A 0.4C-2Si-1Cr-1Mo steel with an ultrafine elongated grain (UFEG) structure and an ultrafine equiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 773 K and subsequent annealing at 973 K. A static three-point bending test was conducted at ambient temperature and at 77 K. The strength-toughness balance of the developed steels was markedly better than that of conventionall...

Many delamination failure criteria based on fracture toughness have been suggested over the past few decades, but most only covered the region containing mode I and mode II components of loading because that is where toughness data existed. With new analysis tools, more 3D analyses are being conducted that capture a mode III component of loading. This has increased the need for a fracture crite...

Channeling cracks in low-k dielectrics have been observed to be a key reliability issue for advanced interconnects. The constraint effect of surrounding materials including stacked buffer layers has been studied. This paper analyzes the effect of interfacial delamination on the fracture condition of brittle thin films on elastic substrates. It is found that stable delamination along with the gr...

Delamination of residually stressed thin film strips is analyzed to expose the dependence on strip width and filmysubstrate elastic mismatch. Isotropic films and substrates are assumed. The residual stress in the film is tensile and assumed to originate from mismatch due to thermal expansion or epitaxial deposition. Full and partial delamination modes are explored. In full delamination, the int...

Millions of years of evolution have adapted spider webs to achieve a range of properties, including the well-known capture of prey, with efficient use of materials. One feature that remains poorly understood is the attachment disc, a network of silk fibers that mechanically anchors a web to its environment. Experimental observations suggest that one possible attachment disc adheres to a substra...

A mixed—mode delamination test procedure was developed combining double cantilever beam (DCB) mode I loading and end-notch fixture (ENF) mode II loading on a split unidirectional laminate. By loading with a lever, a single applied load simultaneously produces mode I and mode II bending loads on the specimen. This mixed-mode bending (MMB) test was analyzed using both finite-element procedures an...