Toughness is a complex material characteristic that is viewed from multiple aspects and is influenced by numerous factors. It is very important to have ability to assess toughness, i.e. to determine ductile or brittle material behaviour at any specific time. Beside total impact energy obtained at Charpy instrumented pendulum, the use of additional parameters such as lateral extension measuremen...

Relationships between crack initiation and crack growth toughness are reviewed by examining the crack tip fields and microscopic (local) and macroscopic (continuum) fracture criteria for the onset and continued quasi-static extension of cracks in ductile materials. By comparison of the micromechanisms of crack initiation via transgranular cleavage and crack initiation and subsequent growth via ...

Severe plastic deformation (SPD) is one of the processes used to refine the microstructure of materials. Equal Channel Angular Extrusion (ECAE) is the most common method of SPD. In this study, AL-6063grain refinement was performed using the Equal Channel Angular Extrusion method. The material was extruded up to 6 passes at a temperature of 200°C following route A. A suitable die sets equipped w...

In spite of their popularity in fulfilling aesthetic requirements, plastic brackets still present some disadvantages because of their low elastic modulus, decreased fracture toughness, and reduced wear resistance. Fibre-reinforced composites are well established in dentistry and consist of a polymer matrix in which reinforcing fibres are embedded. Stress is transferred from the polymer matrix t...

Ambientto elevated-temperature fracture and fatigue-crack growth results are presented for five MoMo3Si-Mo5SiB2–containing -Mo matrix (17 to 49 vol pct) alloys, which are compared to results for intermetallic-matrix alloys with similar compositions. By increasing the -Mo volume fraction, ductility, or microstructural coarseness, or by using a continuous -Mo matrix, it was found that improved fr...

Primate species often eat foods of different physical properties. This may have implications for tooth structure and wear in those species. The purpose of this study was to examine the mechanical defenses of leaves eaten by Alouatta palliata from different social groups at Hacienda La Pacifica in Costa Rica. Leaves were sampled from the home-ranges of groups living in different microhabitats. S...

The effect of microstructural variations on the tensile and fracture toughness properties of Alloy 718 welds is reviewed. The microstructural parameters surveyed include heat treatment, longterm thermal aging and neutron irradiation. The two heat treatments that were characterized include the conventional heat treatment, per ASTM B637, and a modified heat treatment designed to improve the tough...

In order to replicate the fracture behavior of the intact human skull under impact it becomes necessary to develop a material having the mechanical properties of cranial bone. The most important properties to replicate in a surrogate human skull were found to be the fracture toughness and tensile strength of the cranial tables as well as the bending strength of the three-layer (inner table-dipl...