The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Ali Fatemi - One of the best experts on this subject based on the ideXlab platform.
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strain Controlled Fatigue properties of steels and some simple approximations
International Journal of Fatigue, 2000Co-Authors: M L Roessle, Ali FatemiAbstract:Abstract In this study, first strain-Controlled deformation and Fatigue data are reported and compared for several steels most commonly used in the ground vehicle industry. Correlations between monotonic tensile data and constant amplitude strain-Controlled Fatigue properties are then investigated, and validity of some of the more commonly used methods of estimating Fatigue properties is examined. A simple method requiring only hardness and modulus of elasticity is proposed for estimation of the strain–life curve. Prediction capability of this method is evaluated for steels with hardness between 150 and 700 HB and compared with several other methods proposed in the literature. The proposed method is shown to provide good approximations of the strain–life curve.
Michelle Hill - One of the best experts on this subject based on the ideXlab platform.
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Strain Controlled Fatigue Testing of Additive Manufactured Titanium Alloy Ti-6Al-4V
ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2020Co-Authors: Rob Plaskitt, Andrew Halfpenny, Michelle HillAbstract:This paper describes strain Controlled Fatigue testing of a titanium Ti-6Al-4V alloy, additive manufactured by “electron beam melting” (EBM). The EBM material is manufactured in two conditions; with no post-manufacture heat treatment (“As-Built”) and after a hot isostatic pressing (HIP) treatment. The EBM HIP treatment condition is manufactured in three build orientations; vertical, horizontal and at 45°. The Fatigue test results for these EBM material conditions are compared with those for similar titanium Ti-6Al-4V alloy powder, manufactured by powder metallurgy hot-isostatic pressing (PM HIP), and for similar titanium Ti-6Al-4V alloy manufactured by traditional wrought mill into bar and sheet material.The strain-life Fatigue damage model and Fatigue characterisation method used to fit Fatigue test results from traditional manufacturing methods (wrought and PM HIP) appears to be applicable to the additive layer manufacturing method (EBM) for this titanium Ti-6Al-4V alloy material.The EBM As-Built and HIP conditions in the low-cycle region all show similar Fatigue performance. This is expected given their similarity in tensile strength. The effect of the HIP on the EBM additive manufactured material is seen in the high-cycle region with much better Fatigue performance. This is expected as the HIP treatment reduces porosity in the material and improves the Fatigue life. The three EBM HIP build orientations all show very similar Fatigue performance, though the vertical has slightly longer lives than the corresponding horizontal and 45° build orientations. It is not possible to identify whether these slightly longer lives are because of a build orientation difference, a build-to-build difference, or an effect of powder recycling.In conclusion, Fatigue tests on additive manufactured material, including both manufacturing process and any post manufacturing treatment, is considered essential because the Fatigue performance of additive manufactured material cannot be inferred from tensile tests or from comparable wrought material.
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Strain Controlled Fatigue Testing of Additive Manufactured Titanium Alloy Ti-6Al-4V
ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2019Co-Authors: Rob Plaskitt, Andrew Halfpenny, Michelle HillAbstract:This paper describes strain Controlled Fatigue testing of a titanium Ti-6Al-4V alloy, additive manufactured by “electron beam melting” (EBM). The EBM material is manufactured in two conditions; with no post-manufacture heat treatment (“As-Built”) and after a hot isostatic pressing (HIP) treatment. The EBM HIP treatment condition is manufactured in three build orientations; vertical, horizontal and at 45°. The Fatigue test results for these EBM material conditions are compared with those for similar titanium Ti-6Al-4V alloy powder, manufactured by powder metallurgy hot-isostatic pressing (PM HIP), and for similar titanium Ti-6Al-4V alloy manufactured by traditional wrought mill into bar and sheet material.
M L Roessle - One of the best experts on this subject based on the ideXlab platform.
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strain Controlled Fatigue properties of steels and some simple approximations
International Journal of Fatigue, 2000Co-Authors: M L Roessle, Ali FatemiAbstract:Abstract In this study, first strain-Controlled deformation and Fatigue data are reported and compared for several steels most commonly used in the ground vehicle industry. Correlations between monotonic tensile data and constant amplitude strain-Controlled Fatigue properties are then investigated, and validity of some of the more commonly used methods of estimating Fatigue properties is examined. A simple method requiring only hardness and modulus of elasticity is proposed for estimation of the strain–life curve. Prediction capability of this method is evaluated for steels with hardness between 150 and 700 HB and compared with several other methods proposed in the literature. The proposed method is shown to provide good approximations of the strain–life curve.
G Zhang - One of the best experts on this subject based on the ideXlab platform.
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length scale Controlled Fatigue mechanisms in thin copper films
Acta Materialia, 2006Co-Authors: G Zhang, C A Volkert, Ruth Schwaiger, Patrick Wellner, Eduard Arzt, O KraftAbstract:Systematic investigations of Fatigue damage and dislocation structures in thin Cu films with different thicknesses (0.2–3.0 lm) and grain sizes (0.3–2.1 lm mean diameter) were carried out using focused ion beam microscopy and transmission electron microscopy. The morphologies of Fatigue-induced extrusions, cracks, and dislocation structures were studied and found to be Controlled by film thickness and grain size. When either of these length scales is decreased below roughly 1 lm, the typical dislocation wall and cell structures found in Fatigued coarse-grained bulk materials no longer develop and are replaced by individual dislocations. Similarly, the typical surface damage of Fatigued bulk metals, such as extrusions and cracks near extrusions, is gradually suppressed and replaced by damage that is localized at interfaces, such as cracks, grooves, and voids along grain and twin boundaries. This gradual transition from damage characteristic of bulk metals to damage localized at interfaces is attributed to constraints on dislocation activity at submicrometer length scales. Based on the experimental results and a theoretical analysis of extrusion formation, a mechanistic map of Fatigue damage behavior is proposed that summarizes this length scale dependence.
Rob Plaskitt - One of the best experts on this subject based on the ideXlab platform.
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Strain Controlled Fatigue Testing of Additive Manufactured Titanium Alloy Ti-6Al-4V
ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2020Co-Authors: Rob Plaskitt, Andrew Halfpenny, Michelle HillAbstract:This paper describes strain Controlled Fatigue testing of a titanium Ti-6Al-4V alloy, additive manufactured by “electron beam melting” (EBM). The EBM material is manufactured in two conditions; with no post-manufacture heat treatment (“As-Built”) and after a hot isostatic pressing (HIP) treatment. The EBM HIP treatment condition is manufactured in three build orientations; vertical, horizontal and at 45°. The Fatigue test results for these EBM material conditions are compared with those for similar titanium Ti-6Al-4V alloy powder, manufactured by powder metallurgy hot-isostatic pressing (PM HIP), and for similar titanium Ti-6Al-4V alloy manufactured by traditional wrought mill into bar and sheet material.The strain-life Fatigue damage model and Fatigue characterisation method used to fit Fatigue test results from traditional manufacturing methods (wrought and PM HIP) appears to be applicable to the additive layer manufacturing method (EBM) for this titanium Ti-6Al-4V alloy material.The EBM As-Built and HIP conditions in the low-cycle region all show similar Fatigue performance. This is expected given their similarity in tensile strength. The effect of the HIP on the EBM additive manufactured material is seen in the high-cycle region with much better Fatigue performance. This is expected as the HIP treatment reduces porosity in the material and improves the Fatigue life. The three EBM HIP build orientations all show very similar Fatigue performance, though the vertical has slightly longer lives than the corresponding horizontal and 45° build orientations. It is not possible to identify whether these slightly longer lives are because of a build orientation difference, a build-to-build difference, or an effect of powder recycling.In conclusion, Fatigue tests on additive manufactured material, including both manufacturing process and any post manufacturing treatment, is considered essential because the Fatigue performance of additive manufactured material cannot be inferred from tensile tests or from comparable wrought material.
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Strain Controlled Fatigue Testing of Additive Manufactured Titanium Alloy Ti-6Al-4V
ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2019Co-Authors: Rob Plaskitt, Andrew Halfpenny, Michelle HillAbstract:This paper describes strain Controlled Fatigue testing of a titanium Ti-6Al-4V alloy, additive manufactured by “electron beam melting” (EBM). The EBM material is manufactured in two conditions; with no post-manufacture heat treatment (“As-Built”) and after a hot isostatic pressing (HIP) treatment. The EBM HIP treatment condition is manufactured in three build orientations; vertical, horizontal and at 45°. The Fatigue test results for these EBM material conditions are compared with those for similar titanium Ti-6Al-4V alloy powder, manufactured by powder metallurgy hot-isostatic pressing (PM HIP), and for similar titanium Ti-6Al-4V alloy manufactured by traditional wrought mill into bar and sheet material.
