The fracture and fatigue properties of a newly developed bulk metallic glass alloy, Zr41.2Ti13.8Cu12.5 Ni10Be22.5 (at. pct), have been examined. Experimental measurements using conventional fatigue precracked compact-tension C(T) specimens (,7-mm thick) indicated that the fully amorphous alloy has a plane-strain fracture toughness comparable to polycrystalline aluminum alloys. However, signific...

We study the problem of atomic scale fracture using the recently developed quasicontinuum method in which there is a systematic thinning of the atomic-level degrees of freedom in regions where they are not needed. Fracture is considered in two distinct settings. First, a study is made of cracks in single crystals, and second, we consider a crack advancing towards a grain boundary (GB) in its pa...

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...

The fatigue micro crack initiation and propagation tests of a TiAl alloy with 8% Nb content were carried out by using scanning electron microscopy in situ technology at room temperature and at 750 C. These results indicated that the fatigue micro crack initiation was mainly caused by the stress concentration at room temperature, but at an elevated temperature (750 C) the multi-cracks were cau...

Cracks cause to change dynamic response of beams and make discontinuity in slope of the deflection of the beams. The dynamic analysis of the Euler-Bernoulli cracked beam on the elastic foundation subjected to the concentrated load is presented in this paper. The stiffness of the elastic foundation and elastic supports influence on vibrational characteristics of the cracked beam. The Dynamic Gre...

statement of problem: dental resin composites are becoming prevalent in restorative dentistry and have almost replaced amalgam nowadays. consequently, their mechanical properties and durability are critical. objectives: the aim of this study was to produce pyrex glass nano-particles by wet milling process and use them as reinforcement in dental resins for anterior restorations and then examinat...

Fracture toughness resistance curves describe a material's resistance against crack propagation. These curves are often used to characterize biomaterials like bone, nacre or dentin as these materials commonly exhibit a pronounced increase in fracture toughness with crack extension due to co-acting mechanisms such as crack bridging, crack deflection and microcracking. The knowledge of appropriat...