On the Prediction of Uniaxial Tensile Behavior Beyond the Yield Point of Wrought and Additively Manufactured Ti-6Al-4V (original) (raw)
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The capabilities of metal additive manufacturing (AM) are evolving rapidly thanks to both increasing industry demand and improved scientifi c understanding of the process. This article provides an overview of AM of the Ti-6Al-4V alloy, which has essentially been used as a yardstick to gauge the capability of each metal AM process developed to date. It begins by summarizing the metal AM processes existing today. This is followed by a discussion of the macro-and microstructural characteristics, defects, and tensile and fatigue properties of AM Ti-6Al-4V by selective laser melting, laser metal deposition (both powder and wire), and selective electron-beam melting compared to non-AM Ti-6Al-4V. The tensile and fatigue properties of as-built AM Ti-6Al-4V (with machined or polished surfaces) can be made comparable, or even superior, to those of Ti-6Al-4V in the most commonly used millannealed condition. However, these properties can exhibit a large degree of scatter and are often anisotropic, affected by AM build orientations. Post-AM surface treatments or both the post-AM surface and heat treatments are necessary to ensure the minimum required properties and performance consistency. Future directions to further unlock the potential of AM of Ti-6Al-4V for superior and consistent mechanical properties are also discussed.
Predicting the tensile properties of additively manufactured Ti-6Al-4V via electron beam deposition
MATEC Web of Conferences
Additively manufactured materials are gaining wide attention owing to the manufacturing benefits as it results in near net shape components. It is well known that the manufacturing processes affects the performance of the components via microstructural features and the mechanical properties. There is an urgent need to understand the processing-structure-property-performance relationship for the materials manufactures via such innovative techniques. Strategies are needed to quantify and modify the mechanical properties. This study assists to design and tailor the process parameters based on the final properties required. Current work predicts the yield strength of additively manufactured Ti-6Al-4V with different post heat treatments. A thermal model predicted by ABAQUS is fed into an implementation of Langmuir equation that predicts the chemistry which is then used in a phenomenological equation predicting the yield strength. The model is confirmed via experiments showing less than 2...
The International Journal of Advanced Manufacturing Technology, 2020
Recent studies have shown that the mechanical properties of Ti alloys produced by additive manufacturing (AM) methods are sensitive to AM process parameters. The mechanical threshold stress (MTS) model is capable of predicting the flow stress behavior of materials; however, the parameters needed in the MTS model are affected by the microstructure that originates from the AM process parameters. To find a relationship between the AM process parameters and the MTS parameters, the effect of process parameters on the mechanical properties of selective laser-melted (SLM) Ti-6Al-4V samples was studied. As the MTS model is sensitive to the microstructure, only near fully dense samples were considered.
Journal of Alloys and Compounds, 2018
Wire þ Arc Additive Manufacturing (WAAM) is a promising manufacturing process for producing large aerospace components. Based on welding technology, the process is highly affordable, has a very high deposition rate and is not limited by chamber size. Ti-6Al-4V is a promising candidate material for this technology given that it is extensively used in aerospace applications and some large, high buy-fly ratio components can be more efficiently produced by WAAM than via the conventional machining from billet approach. There is currently limited knowledge about whether additional post processes including heat treatments and hot isostatic pressing are necessary to unlock the optimal mechanical properties of Ti-6Al-4V components produced by WAAM. This work explores a range of different post process treatments and the effects on the microstructure and tensile properties of Ti-6Al-4V components produced by WAAM. The relatively slow cooling rate (10-20Ks À1) during the b-a transformation produced Wid-manst€ atten-a and offered an optimal balance between strength and ductility. Hot Isostatic Pressing (HIPing) removed gas porosity but was not effective in improving strength or ductility. Residual tensile stresses in as-built components severely impair ductility and should be removed through stress relief treatments.
On the hot deformation behavior of Ti-6Al-4V made by additive manufacturing
Journal of Materials Processing Technology, 2021
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Materials
An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consist...
MATEC Web of Conferences, 2020
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Mechanical properties and strain rate sensitivity of 3D laserdeposited Ti-6Al-4V alloy
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Ti-6Al-4V has become the most common material in titanium alloy. Due to High specific strength, low density and excellent mechanical properties, it has been used in not only living, sports goods but also aerospace, defense industries. Usually these products have complex geometry, so there are a lot of limitations in general manufacturing process. Especially in weapon systems, applied loadings are severe therefore choice of materials is very important. 3D printing method is useful for manufacturing these complicated structure and suitable to discontinued, superannuated part of products. In this study, specimen for experiments is turned out by using 3d laser deposition technology which metal powder is injected into the focused beam of a high-powered laser. While lots of studies are mainly concerned with normal process, it is not commonly researched for metallic materials forming through 3D printing. In the 10-3~1 0 3 /s strain rates range, two kinds of plate samples and LDAM Ti-6Al-4V were performed using universal testing machine and SHPB for dynamic material properties. Simplified Johnson-Cook constitutive equation parameters produced from these experiments.
Plasticity and damage mechanisms in Ti-6Al-4V printed with selective laser melting
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The ability to create complex geometries with tailored material properties has brought interest in using additive manufacturing (AM) techniques in various industrial applications. However, the complex relationship between AM process parameters, microstructure, and resultant properties of metals needs to be fully understood for the widespread use of metal AM. In this study, selective laser melting is used to print Ti-6Al-4V. In-situ tensile tests with concurrent detailed microstructural analysis using electron backscatter diffraction, electron channeling contrast imaging, and digital image correlation are performed to understand the damage mechanism and its relation to the microstructure. Our results show that the as-printed part develops a hierarchical microstructures, consisting of primary, secondary, and tertiary {\alpha}^' martensite. This hierarchical structure is formed as a result of cyclic heat treatment during the course of selective laser melting. Upon deformation, stra...