Fractography

About: Fractography is a research topic. Over the lifetime, 5043 publications have been published within this topic receiving 86068 citations.

A fractographic investigation of PMMA bone cement focusing on the relationship between porosity reduction and increased fatigue life.

Abstract: Fracture surfaces of both monotonic and fatigue loaded bone cement samples were examined to investigate the fractographic characteristics of PMMA. Classic cleavage step river patterns were observed on all monotonically loaded samples, running downstream in the direction of crack propagation. All fatigue cracks initiated at internal pores and the direction of crack propagation of many cracks was discernible. Porosity, pore size, and pore size distribution were found to affect the crack initiation and fatigue behavior of bone cement. Statistical analysis revealed a strong negative correlation between two-dimensional porosity present on the fracture surfaces and the cycles to failure. The fractographic observations of these fatigue samples elucidate one reason why porosity reduction by centrifugation or vacuum mixing increases the fatigue life of PMMA bone cement.

Fatigue crack growth in metals and alloys: mechanisms and micromechanics

Abstract: Fatigue crack growth has been studied using several new experimental tools in the past ten years. The observation of fatigue cracks during growth under high resolution conditions has shown that crack advance is an intermittent process. These results, when combined with measurements of crack opening, displacements, crack closure, crack tip strains, fractography, and other information, leads to a reasonable understanding of many intrinsic aspects of fatigue crack growth at ambient temperature in a number of metallic alloys. Models of fatigue crack growth are reviewed from the perspective of this understanding. No model has achieved the capability of predicting fatigue crack growth from a description of microstructural and mechanical properties. The factors limiting a deeper understanding of fatigue crack growth are also more clearly defined, which gives some direction for future research. This paper is a critical review of crack growth mechanisms, mainly for large fatigue cracks subject to constant ...

Effect of rhenium addition on fracture toughness of tungsten at elevated temperatures

Abstract: Fracture toughness tests of tungsten and tungsten-rhenium alloy specimens were carried out at elevated temperatures. Temperature dependence of fracture toughness and effect of rhenium content on fracture toughness were investigated. Although fracture toughnesses of three kinds of specimens with rhenium contents of 0, 5 and 10 wt% were almost identical at room temperature, fracture toughness at elevated temperatures increased with increasing rhenium content. The brittle-ductile transition, similar to steels, and subsequent transition of the fracture mode from ductile dimple to intergranular were observed for all three kinds of specimens. With increasing rhenium content, the transition temperatures increased. A significant grain growth was found, not for tungsten-rhenium alloy specimens, but for a tungsten specimen without rhenium in a temperature range higher than the recrystallizing temperature, which resulted in transition of the fracture mode from dimple to intergranular.

Fracture and impact behaviours of hollow micro-sphere/epoxy resin composites

Abstract: Fracture and impact behaviours of glass-hollow micro-sphere/epoxy resin composites are studied in terms of fracture toughness, fractography, flexural properties and impact force. Volume fraction of micro-spheres for the composites was varied up to 0.65. The addition of micro-spheres did not enhance the fracture toughness of the composites despite the presence of pinning mechanism. Performance of reducing the impact force was enhanced as the content of micro-spheres increased but at the expense of other properties. (a) For the covering entry of this conference, please see ITRD abstract no. E204495.