FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2341484492> ?p ?o ?g. }

• W2341484492 abstract "Two-phase titanium alloys dominate the aerospace engine industry and their use in jet engines is not replaceable in the short to medium term. Cyclic loading during flight makes fatigue performance one of the key considerations in aerospace applications. The effect of titanium alloy microstructure on fatigue behaviour has been extensively investigated but there remain questions about the effects of Regions of crystallographically aligned α grains, which are known as ‘macrozones’. We currently have limited knowledge about the contributions of macrozones to crack initiation and crack propagation. The aim of this thesis is to provide new understanding of the effect of macrozones on fatigue behaviour and to propose a processing window for macrozone-free microstructures.It is expected that the presence of macrozones will influence both fatigue crack initiation and propagation. The hypothesis is that dislocations pile up on the interface between two macrozones and accumulate strain on this interface. The accumulated strain consequently leads to crack initiation. The microcrack growth in macrozones is subsequently faster than in random orientations because the aligned grains in macrozones provide lower resistance to transmission across grain boundaries.In order to characterize the effect of macrozones on fatigue behaviour we conducted four-point bending high-cycle fatigue tests, which have the advantage of uniform tensile stress on the tensile surface. Samples made from as-forged Ti-6Al-4V were used for the investigation of fatigue crack initiation, and samples with micronotches made from both as-forged and hot isostatic pressed Ti-6Al-4V were used for the investigation of crack propagation. The crack initiation and propagation were tracked by replicas taken at intervals during testing, and crack propagation rates were calculated. Electron Backscattered Diffraction was used to identify the texture of macrozones, from which the Schmid factor distributions were calculated to identify the potential activated slip systems combined with other slip analysis like slip trace analysis. Hot compression tests were carried out at different temperatures and strain rates on cylindrical Ti-6Al-4V samples with as-cast microstructures to identify a processing window for a macrozone- free material.It was found that fatigue cracks can be initiated between two macrozones with different primary deformation modes. Slip is effectively continuous in a macrozone due to aligned α grains but arrested on the macrozone boundary with high-angle misorientation, which leads to strain accumulation on the boundary and initiates a crack. A misorientation crack factor parameter is proposed based on Electron Backscattered Diffraction data in this work to quantify the effect of macrozones on crack initiations based on deformation modes, misorientation and boundary trace. The calculated misorientation crack factor results of macrozones on crack initiation areas on tested samples are consistent with the experimental results.Furthermore, we found that microcrack growth is sensitive to the presence of macrozones: microcrack propagation was faster in a macrozone than in random orientations. Transgranular microcrack growth is mostly along either basal or prismatic planes in a macrozone with reasonable effective stress intensity factor and not arrested by grain boundaries. The β phase on α grain boundaries in macrozones in two-phase titanium alloys provides minimal resistance to microcrack propagation.Finally, this thesis describes a processing window, which gives macrozone-free titanium alloys based on hot compression results. Hot compression tests of the two- phase titanium alloy Ti-6Al-4V with as-cast microstructures indicate that macrozones mostly form at low temperature (i.e. 850 °C and below) and are enhanced by subsequent annealing. Hot working close to the β transus gives more chance of a macrozone-free product." @default.
• W2341484492 created "2016-06-24" @default.
• W2341484492 creator A5011420834 @default.
• W2341484492 date "2016-01-01" @default.
• W2341484492 modified "2023-09-28" @default.
• W2341484492 title "Microtexture and macrozones in two-phase titanium alloys" @default.
• W2341484492 doi "https://doi.org/10.4225/03/58ab80e2d20bf" @default.
• W2341484492 hasPublicationYear "2016" @default.
• W2341484492 type Work @default.
• W2341484492 sameAs 2341484492 @default.
• W2341484492 citedByCount "0" @default.
• W2341484492 crossrefType "dissertation" @default.
• W2341484492 hasAuthorship W2341484492A5011420834 @default.
• W2341484492 hasConcept C112950240 @default.
• W2341484492 hasConcept C127413603 @default.
• W2341484492 hasConcept C131850400 @default.
• W2341484492 hasConcept C146978453 @default.
• W2341484492 hasConcept C159985019 @default.
• W2341484492 hasConcept C167740415 @default.
• W2341484492 hasConcept C191897082 @default.
• W2341484492 hasConcept C192562407 @default.
• W2341484492 hasConcept C2780026712 @default.
• W2341484492 hasConcept C28539199 @default.
• W2341484492 hasConcept C39643299 @default.
• W2341484492 hasConcept C47908070 @default.
• W2341484492 hasConcept C59085676 @default.
• W2341484492 hasConcept C75512024 @default.
• W2341484492 hasConcept C78519656 @default.
• W2341484492 hasConcept C87210426 @default.
• W2341484492 hasConcept C87976508 @default.
• W2341484492 hasConcept C8953137 @default.
• W2341484492 hasConceptScore W2341484492C112950240 @default.
• W2341484492 hasConceptScore W2341484492C127413603 @default.
• W2341484492 hasConceptScore W2341484492C131850400 @default.
• W2341484492 hasConceptScore W2341484492C146978453 @default.
• W2341484492 hasConceptScore W2341484492C159985019 @default.
• W2341484492 hasConceptScore W2341484492C167740415 @default.
• W2341484492 hasConceptScore W2341484492C191897082 @default.
• W2341484492 hasConceptScore W2341484492C192562407 @default.
• W2341484492 hasConceptScore W2341484492C2780026712 @default.
• W2341484492 hasConceptScore W2341484492C28539199 @default.
• W2341484492 hasConceptScore W2341484492C39643299 @default.
• W2341484492 hasConceptScore W2341484492C47908070 @default.
• W2341484492 hasConceptScore W2341484492C59085676 @default.
• W2341484492 hasConceptScore W2341484492C75512024 @default.
• W2341484492 hasConceptScore W2341484492C78519656 @default.
• W2341484492 hasConceptScore W2341484492C87210426 @default.
• W2341484492 hasConceptScore W2341484492C87976508 @default.
• W2341484492 hasConceptScore W2341484492C8953137 @default.
• W2341484492 hasLocation W23414844921 @default.
• W2341484492 hasOpenAccess W2341484492 @default.
• W2341484492 hasPrimaryLocation W23414844921 @default.
• W2341484492 hasRelatedWork W1980045854 @default.
• W2341484492 hasRelatedWork W1988140476 @default.
• W2341484492 hasRelatedWork W2005158444 @default.
• W2341484492 hasRelatedWork W2020048050 @default.
• W2341484492 hasRelatedWork W2022846846 @default.
• W2341484492 hasRelatedWork W2023233203 @default.
• W2341484492 hasRelatedWork W2034671017 @default.
• W2341484492 hasRelatedWork W2053972349 @default.
• W2341484492 hasRelatedWork W2081773897 @default.
• W2341484492 hasRelatedWork W2084936113 @default.
• W2341484492 hasRelatedWork W2162785677 @default.
• W2341484492 hasRelatedWork W2509781792 @default.
• W2341484492 hasRelatedWork W2619190872 @default.
• W2341484492 hasRelatedWork W2731271135 @default.
• W2341484492 hasRelatedWork W2759581435 @default.
• W2341484492 hasRelatedWork W2918331039 @default.
• W2341484492 hasRelatedWork W3046125014 @default.
• W2341484492 hasRelatedWork W3150638769 @default.
• W2341484492 hasRelatedWork W3176812072 @default.
• W2341484492 hasRelatedWork W3187206552 @default.
• W2341484492 isParatext "false" @default.
• W2341484492 isRetracted "false" @default.
• W2341484492 magId "2341484492" @default.
• W2341484492 workType "dissertation" @default.