Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"Tensile Deformation"”.
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A model treating tensile deformation of semi-crystalline polymers
… occurs, followed by a hardening at large deformations. The true stress-strain dependencies clearly demonstrate that the tensile deformation of semi-crystalline polymers follows a common scheme with changes in the mechanism at critical strains. <br> <br>Our measurements of true stress-true …
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A microtexture based analysis of surface roughening in ductile metals during tensile deformation
… occurrence of parallel surface ridges during the deformation of two specific ductile metal alloys, namely AISI 430 ferritic stainless steel and an aluminium alloy designated AA3002. The investigation considers, in particular, the development of parallel ridges during uniaxial tension, and their …
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A microtexture based analysis of surface roughening in ductile metals during tensile deformation
… occurrence of parallel surface ridges during the deformation of two specific ductile metal alloys, namely AISI 430 ferritic stainless steel and an aluminium alloy designated AA3002. The investigation considers, in particular, the development of parallel ridges during uniaxial tension, and their …
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The production and annealing of point defects produced by quenching and by tensile deformation in pure gold and silver
… of six nines purity were strained at 4.Z K by tensile deformation and were quenched from 700 ± 40 oC. For gold deformed at 4.ZoK the most prominent annealing is observed in the region between ZOoC and 70°C. For this case the annealing at 40°C obeys second order kinetics and the effective energy …
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Understanding of the mechanical response of semicrystalline polymers based on the block-like substructure of crystalline lamellae
… models of semi-crystalline polymer systems under tensile deformation. Splitting the total tensile deformation into elastic and plastic parts shows four characteristic points (A,B,C and D) from the true stress-true strain curves, where the differential compliance and recovery property change. It …
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Effect of thermomechanical processing on the surface roughening of AA6061
… After rolling. the plates are levelled by a tensile stretching process and it is during this process that surface roughening of the plates can arise. Three of these plates exhibited severe roughening and the other 12 mm thick plate exhibited mild surface roughening during the stretch …
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Mechanical and optical characterization of force induced chemical reactions in solid state linear polymers
… (SP), reacts to a merocyanine (MC) form under tensile force when linked into a polymer backbone. This reaction is reversible and can be driven toward either SP or MC photochemically. Reaction of SP to MC (activation) is accompanied by the emergence of a strong color change and fluorescence …
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Understanding the Yield Behaviour of Single Crystal Ni-based Superalloys
… microscopy (HRTEM) has been undertaken on tensile specimens of the single crystal Ni-based superalloys CMSX-4 under different deformation conditions. In a two-phase superalloy, during early stages of tensile deformation, dislocations nucleate in the γ matrix phase and glide in the narrow …
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A coupled theory for diffusion of hydrogen and large elastic-plastic deformations of metals
… diffusion of heat, and large elastic-plastic deformations of metals is developed. Our theoretical framework places the widely-used notion of an "equilibrium" between hydrogen residing in normal interstitial lattice sites and hydrogen trapped at microstructural defects, within a …
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Synthesis and characterization of silk-inspired thermoplastic polyurethane elastomers
… angle of ±20⁰ from the strain direction during tensile deformation.
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Spinning of collagen fibers and characterizing thermal, mechanical, tensile and structural properties
… with higher denaturation temperature and lower tensile deformation.
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Investigation of new synchrotron X-ray and neutron techniques for local crystallographic analysis of Ni-based single crystal superalloys
… across the microstructure as well as during deformation. Firstly, a monochromatic synchrotron X-ray source was used to investigate a high misfit Ni-based single crystal superalloy, which involved rocking the sample to ensure the Bragg condition was maintained during in situ loading at …
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Aspects of serrated flow in aluminium alloys
Uniaxial tensile testing has been undertaken on a range of aluminium base alloys. Material investigated included commercial binary Al-Mg (5182), ternary Al-Mg-Si (6061) and quaternary Al-Cu-Mn-Si (2014) as well as experimental alloys containing 2at.% additions of Ag, Mg and Zn to commercially pure …
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Friction stir welding of high temperature alloys
… structure facilitated globularization during tensile deformation at 625 ºC.</p> <p>Mechanical properties were correlated with microstructure in FSW materials. Improved mechanical properties were observed for ODS alloys due to grain refinement. An effort was made to predict room temperature …
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Design of Lightweight Magnesium Alloys: Processing, Microstructure and Properties
… Unfortunately, magnesium shows di erent deformation depending on the loading direction: its tensile deformation resembles typical metallic behavior while its compression has a unique, twinning region of the stress-strain curve. This asymmetry is unreliable/ undesirable in practical …
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Determining soft segment structure-property effects in the enhancement of segmented polyurethane performance
… hard domain shearing during in-situ tensile deformation yields oriented hard blocks that align at a preferred tilt angle of ±60° from the strain direction. Extensive alignment and orientation of the moderately-ordered PEO soft segments occurred during deformation, which was consistent …
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Atomistic Molecular Dynamics Studies of Grain Boundary Structure and Deformation Response in Metallic Nanostructures
… how local grain boundary structure affects deformation behavior through the quantitative estimation of various plasticity mechanisms, such as dislocation emission and grain boundary sliding. The effects of strain rate and temperature on the plastic deformation process were also investigated. …
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Roles of surface finish and hydrogen availability on the tensile properties of 1018 steel in hydrogen environments
Uniaxial tensile tests were performed on AISI 1018 steel specimens. Tests were conducted both in air and while the specimens were undergoing electrolytic hydrogen charging. Specimens with three different surface finishes were tested at various cathodic charging current densities. The tensile …
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Hot tearing and constitutive behaviour of semi-solid aluminum alloys
… both hot tearing formation and semi-solid deformation is essential. In this study, the mechanisms of hot tearing and semi-solid deformation have been investigated via two novel techniques: x-ray micro-tomography on material deformed in the semi-solid region, and development of a three phase …
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