We have studied thin film instabilities and in particular buckling driver delami-nation of thin films on rigid substrates. In the first part we studied residual stressin molybdenum thin films deposited by magnetron sputtering. With these resultswe can deposit a film with high compressive stresses for delamination. In the secondpart, compressive stressed layers are used to induce...

Neural crest cells (NCC) have the particularity to invade the environment where they differentiate after separation from the neuroepithelium. This process, called delamination, is strikingly different between cranial and trunk NCCs. If signalings controlling slow trunk delamination start being deciphered, mechanisms leading to massive and rapid cranial outflow are poorly documented. Here, we sh...

1 SUMMARY A mixed-mode delamination test procedure was developed combining double cantilever beam (DCB) mode I loading and end notch flexure (ENF) mode II loading on a split unidirectional laminate. By loading the specimen 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 finit...

The cracking and delamination of TiN-coated hardmetals (WC-Co cemented carbides) when subjected to Brale indentation were studied. Experimental variables were substrate microstructure related to low (6%wt. Co) and medium (13%wt. Co) binder content, and surface finishes associated with grinding and polishing stages before film deposition. Brale indentation tests were conducted on both coated and...

Micromechanical models are developed to explore the effect of embedded metal layers upon thermal cycling delamination failure of thermal barrier coatings (TBCs) driven by thickening of a thermally grown oxide (TGO). The effects of reductions in the steady-state (i.e. maximum) energy release rate (ERR) controlling debonding from large interface flaws and decreases in the thickening kinetics of T...

Drilling is the most frequently employed operation of secondary machining for fiber-reinforced materials owing to the need for joining structures. Delamination is among the serious concerns during drilling. Practical experience proves the advantage of using such special drills as saw drill, candle stick drill, core drill and step drill. The experimental investigation described in this paper exa...

The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs) was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF) for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray ...

Pyramidal truss sandwich cores with relative densities 4q in the range 1–10% have been made from carbon fiber reinforced polymer laminates using a snap-fitting method. The measured quasi-static uniaxial compressive strength increased with increasing 4q from 1 to 11 MPa over the relative density range investigated here. A robust face-sheet/ truss joint design was developed to suppress truss– fac...

During neural crest ontogeny, an epithelial to mesenchymal transition is necessary for cell emigration from the dorsal neural tube. This process is likely to involve a network of gene activities, which remain largely unexplored. We demonstrate that N-cadherin inhibits the onset of crest delamination both by a cell adhesion-dependent mechanism and by repressing canonical Wnt signaling previously...

Delamination of neural progenitors from the apical adherens junction belt of the neuroepithelium is a hallmark of cerebral cortex development and evolution. Specific cell biological processes preceding this delamination are largely unknown. Here, we identify a novel, pre-delamination state of neuroepithelial cells in mouse embryonic neocortex. Specifically, in a subpopulation of neuroepithelial...