The toughness of Fe-based bulk metallic glasses BMGs has been significantly improved via systematic changes in chemistry. Chemistry changes were selected based on their likely effects on critical elastic constants shown to affect plasticity/toughness in various BMGs, in addition to their recently discovered effects on chemical bonding in these Fe-based systems. The fracture energy obtained on n...

The development of hydrogels for cartilage replacement and soft robotics has highlighted a challenge: load-bearing hydrogels need to be both stiff and tough. Several approaches have been reported to improve the toughness of hydrogels, but simultaneously achieving high stiffness and toughness remains difficult. Here we report that alginate-polyacrylamide hydrogels can simultaneously achieve high...

The fracture toughness is a critical material property for the pyrolytic carbon materials used in mechanical heart-valve prostheses; however, making accurate toughness measurements has traditionally been problematic due to difficulties in fatigue precracking specimens. In this work, a simple, effective, and reliable precracking method is presented where a sharp precrack is "popped in" from a ra...

In the present work, six-layered (Zirconia/Nickel) functionally graded materials were fabricated via powder metallurgy technique (PMT). The microstructure, fracture surface and the elemental analysis of the prepared components were studied, and their linear shrinkage, electrical conductivity, fracture toughness and Vickers hardness were evaluated. The results show that the linear shrinkage of t...

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 ...

A computational approach to the optimization of service properties of two-phase materials (in this case, fracture resistance of tool steels) by varying their microstructure is developed. The main points of the optimization of steels are as follows: (1) numerical simulation of crack initiation and growth in real microstructures of materials with the use of the multiphase finite elements (MPFE) a...

STATEMENT OF PROBLEM Patients' demand for tooth-colored restoratives in the posterior region is increasing. Clinicians use universal nanohybrid resin composites for both anterior and posterior regions. There are few published reports comparing fracture toughness of nonohybrids and that of hybrid composite stored wet and dry. OBJECTIVES To investigate the fracture toughness of three nanohybrid...

magnesium alloys in liquid-phase condition form surface oxide films due to their high rate of oxidation. oxide films enter the melt as a result of surface turbulence, and remain inside the workpiece after solidification. the incoherent nature of their interface causes decreases in mechanical properties and reliability of castings. the effect of critical velocity and greater velocities of enteri...

The fracture toughness and strength of ceramics can be improved with respect to monolithic ceramics by developing graded materials as laminates composed of periodic alternating layers of one material separated by layers of a second material. The second layer must contain residual compressive stresses which are induced during densification because of differential thermal contraction of the layer...

Fracture toughness of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) in both bulk and film forms after sintering at 900°C to 1200°C was measured using both single-edge V-notched beam (SEVNB) 3-point bending and Berkovich indentation. FIB/SEM slice-and-view observation after indentation revealed the presence of Palmqvist radial crack systems after indentation of the bulk materials. Based on crack length measur...