Topic
Fractography
About: Fractography is a research topic. Over the lifetime, 5043 publications have been published within this topic receiving 86068 citations.
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TL;DR: In this article, the performance of molybdenum alloys with rhenium contents of 41-47.5% was evaluated after irradiation at space reactor relevant temperatures.
32 citations
TL;DR: In this article, it is suggested that the basic cause of susceptibility in these alloys is due to the properties of surface film which has been identified as Mg(OH) 2.
32 citations
TL;DR: Fracture toughness of epoxy was determined by quantitative fractography, one of the techniques for brittle materials based on fracture mechanics as mentioned in this paper, which was used to measure the dimensions of the different regions on the fracture surfaces of unnotched samples that were tested to failure under tension.
Abstract: Fracture toughness of epoxy was determined by quantitative fractography, one of the techniques for brittle materials based on fracture mechanics. Two different epoxy systems, an anhydride-cured and an amine-cured epoxy based upon diglycidyl ether of bisphenol A (DGEBA) were studied. Epoxies with different average molar mass between crosslinks (Mc) or crosslink density were prepared by varying the cure profiles. The materials were characterized using differential scanning calorimetry (DSC), dynamic mechanical spectroscopy (DMS), and density measurements. Optical microscopy was used to measure the dimensions of the different regions on the fracture surfaces of unnotched samples that were tested to failure under tension. The fracture toughness values were calculated from the relationship between the measured sizes and fracture stress. Epoxies with lower Mc values or higher crosslink densities have lower fracture toughness values. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 257–268, 1999
32 citations
20 Oct 2014-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a study of microstructure, mechanical properties and corrosion behaviour of a near alpha Ti-5Ta-1.8Nb alloy subjected to cryo-rolling was presented.
Abstract: This paper presents a study of microstructure, mechanical properties and corrosion behaviour of a near alpha Ti–5Ta–1.8Nb alloy subjected to cryo-rolling. Grain size decreased with increase in cryo-rolling strain (ecr), from about 5 µm in the annealed sample down to ~20 nm at a ecr=2.3. Dislocation density initially increased steeply up to ecr=0.69 and then decreased with increasing strain up to 2.3. The decrease in the dislocation density was attributed to the formation and interaction of pile-ups resulting in annihilation of dislocations. Hall–Petch analysis showed two distinct slopes, region I, with a rapid increase in stress and region II with a negligible increase in stress with decrease in grain size. This was explained in terms of changes in dislocation density and grain size. Fractography studies revealed dimples and microvoids in the coarse grained alloy but the nanocrystalline alloy revealed a mixture of shear bands at the surface and smaller ductile dimples at the centre. Evaluation of the corrosion behaviour in boiling and concentrated nitric acid in three phases (liquid, condensate and vapour) of the nanocrystalline samples revealed almost no deterioration of the corrosion resistance of the Ti alloy when compared to the solution annealed alloy.
32 citations
TL;DR: In this article, the relationship between low-cycle fatigue (LCF) strength of austempered ductile iron (ADI) and cast section size and location was investigated. And the effects of section size, location within the heavy-section casting, and austempering temperatures on the LCF strength of ADI were discussed in terms of the graphite nodule morphology and microshrinkage pores.
Abstract: The relationship between low-cycle fatigue (LCF) strength of austempered ductile iron (ADI) and cast section size and location was investigated. Uniaxial LCF tests under strain-control were conducted on a number of different grades of ADIs. These ADIs were selected from four positions in Y-block castings with three section sizes (25, 50, and 100 mm in thickness). LCF specimens were cut from specific locations within the castings, austenitized at 1173 K, and then austempered at 573 and 633 K, respectively. Results indicated that LCF strength of ADI degraded with increasing section size due to deteriorated graphite nodule morphology and presence of more microshrinkage pores as a result of the slower solidification rate. The effects of section size, location within the heavy-section casting, and austempering temperatures on the LCF strength of ADI are discussed in terms of the graphite nodule morphology and microshrinkage pores. Fractography with scanning electron microscopy (SEM) was applied to determine the LCF failure mechanisms and fatigue crack propagation modes.
32 citations