in the present study, the mechanical properties and fracture mechanisms of two powder metallurgy low alloy steels, i.e. distaloy dh and distaloy hp, were investigated. all samples were sintered at 1120 ºc for 30 min in n2/h2 atmosphere. for evaluation of the effect of cooling rate on final properties, samples were cooled from sintering temperature with two different cooling rates. in addition, ...

The slow motion of a crack line is studied via an experiment in which sheets of paper are split into two halves in a "peel-in-nip" (PIN) geometry under a constant load, in creep. The velocity-force relation is exponential. The dynamics of the fracture line exhibits intermittency, or avalanches, which are studied using acoustic emission. The energy statistics is a power law, with the exponent be...

Tight-binding molecular dynamics simulations shed light into the fracture mechanisms and the ideal strength of tetrahedral amorphous carbon and of nanocomposite carbon containing diamond crystallites, two of the hardest materials. It is found that fracture in the nanocomposites, under tensile or shear load, occurs intergrain and so their ideal strength is similar to the pure amorphous phase. Th...

introduction: this study investigated the fatigue and fracture modes of race and protaper rotary instruments. materials & methods: fatigue resistance was evaluated by rotating the files 30 ° or 60 ° and with 2 or 5mm radius of curvature. race taper 06 size 25 and protaper f1 files (n=40) were used. the number of rotations to failure was analyzed by two-way anova and independent sample     t-tes...

BACKGROUND Ceramic surfaces offer excellent tribological properties and for this reason are frequently used in younger patients with osteoarthritis of the hip. However, they may fracture easily owing to low tolerance to tensile and impact stresses in particular. We report a case of early fracture of a currently available ceramic liner in a 44-year-old woman with revision total hip arthroplasty....

The torsion property and rotary fatigue fracture behavior of Smart K file and R reamer made of nickel titanium alloy have been studied by means of Shimadzu Autograph DDS-10T universal tester and man-made cyclic system with curved copper tubes as simulated root canal. The instrument surface and the cyclic fatigue fracture surface have been investigated by optical microscope and scanning electro...

In this study, the fractal dimensions of failure surfaces of vinyl ester based nanocomposites are estimated using two classical methods, Vertical Section Method (VSM) and Slit Island Method (SIM), based on the processing of 3D digital microscopic images. Self-affine fractal geometry has been observed in the experimentally obtained failure surfaces of graphite platelet reinforced nanocomposites ...

Nanomechanical characteristics of standalone silver nanowires (Ag NWs) are a key issue for providing a failure criterion of advanced flexible electrodes that are trending towards smaller radius of curvatures (ROCs). Through in-situ tensile and buckling tests of pentagonal Ag NWs, we demonstrated that the intrinsic fracture strain provides a significant criterion to predict the mechanical and el...