Article
Engineering, Manufacturing
M. Strantza, R. K. Ganeriwala, B. Clausen, T. Q. Phan, L. E. Levine, D. C. Pagan, J. P. C. Ruff, W. E. King, N. S. Johnson, R. M. Martinez, V Anghel, G. Rafailov, D. W. Brown
Summary: This study investigates the effect of laser scan strategy on the three-dimensional residual stress state of L-PBF metallic components. High-energy X-ray diffraction was used to measure residual stress in Ti-6Al-4V bridge components built with different scanning patterns. The observed residual stresses were found to be large, around 1/2 to 3/4 of the yield strength, with higher stresses near the edges of components built with island scan strategies.
ADDITIVE MANUFACTURING
(2021)
Article
Materials Science, Multidisciplinary
Polina Metalnikov, Ali Arslan Kaya, Guy Ben-Hamu, Dan Eliezer
Summary: This study compared the microstructural changes of Ti-6Al-4V alloy prepared by electron beam melting (EBM) and selective laser melting (SLM) in the presence of hydrogen. It was found that SLM Ti6Al-4V with acicular martensitic structure is more vulnerable to hydrogen-induced phase transformation and damage compared to EBM. Additionally, different hydrogen charging environments led to different microstructural changes in EBM Ti-6Al-4V.
MATERIALS CHARACTERIZATION
(2023)
Article
Mechanics
Stephen Daynes, Joseph Lifton, Wen Feng Lu, Jun Wei, Stefanie Feih
Summary: Metallic lattice structures are known for their high specific elastic moduli and strength, but their resistance to fracture is not well understood. In this study, Ti-6Al-4V lattice structures were additively manufactured using selective laser melting, and their fracture toughness characteristics were investigated under Mode-I loading. The results showed that toughness increases with relative density in a power law manner, and a new functional grading optimisation methodology was introduced to increase fracture toughness. After size optimisation, initiation fracture toughness was improved by up to 37%.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2021)
Article
Engineering, Manufacturing
Dylan Agius, Chris Wallbrink, Kyriakos Kourousis
Summary: The design freedom provided by Additive Manufacture (AM) technologies is driving innovation in new directions, but also creating challenges in material characterisation. This paper proposes a model that combines anisotropic yield function with nonlinear multicomponent kinematic hardening rule to accurately simulate the anisotropic behavior of materials like Ti-6Al-4V alloy. The model's performance was evaluated through simulations and showed good agreement with experimental data, demonstrating its efficiency in modeling cyclic stress-strain evolution in different build orientations.
ADDITIVE MANUFACTURING
(2021)
Article
Materials Science, Multidisciplinary
Xinyu Yang, Richard A. Barrett, Noel M. Harrison, Sean B. Leen
Summary: A physically-based, mixed-phase structure-property model is developed for analyzing the microstructure-sensitivity of tensile stress-strain response in additively manufactured Ti-6Al-4V, considering the effects of solutes, grain size, phase volume fraction, and dislocation density. The model incorporates solid-state phase transformation and dislocation density evolution to simulate the effects of martensite dissolution and a -b transformation at high temperature, allowing for rapid process-structure-property prediction and optimization.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
In-Su Kim, Jeong Mok Oh, Sang Won Lee, Jong-Taek Yeom, Jae-Keun Hong, Chan Hee Park, Taekyung Lee
Summary: This study investigated the effects of processing variables on the globularization of AM-processed Ti-6Al-4V alloy, revealing that a combination of solution treatment, low-temperature forging, and subsequent annealing significantly accelerates the process by reducing the path for boundary splitting in fine martensitic laths induced via solution treatment.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Nanoscience & Nanotechnology
R. X. Zhao, J. Wang, T. W. Cao, T. Hu, S. S. Shuai, S. Z. Xu, C. Y. Chen, Z. M. Ren, M. Qian
Summary: This study demonstrates the use of high magnetic field heat treatment to modify the microstructure of a Ti-6Al-4V alloy fabricated by laser-powder bed fusion, resulting in improved mechanical properties. The treatment increased the sub-grain boundaries in the alpha-phase and accelerated the coarsening and globularization of the alpha-phase, leading to enhanced tensile ductility. Furthermore, the treatment induced better alignment of the alpha-variants with the < 11-20 >alpha direction, facilitating the activation of prismatic and basal slips.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Mechanical
Ming Li, Alok Gupta, Chris J. Bennett, Zhu-Feng Yue, Wei Sun, Shan-Tung Tu
Summary: This study aims to establish the mechanical relationship between additive manufactured Titanium alloy and geometrically complex load-bearing aeroengine lightweight structure under cyclic loading. The constitutive behavior of laser powder bed fusion (LPBF) Ti-6Al-4V was characterized through a computational cyclic plasticity model derived from the low cycle fatigue (LCF) test. A finite element (FE) model was developed and experimentally validated to investigate the stress-strain nature and optimize the structure. The results showed that the cracking mode of the bracket was dependent on the local maximum principal stress and exhibited a mixture of opening and shear cracks.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Materials Science, Multidisciplinary
Jay K. Raval, Aamer A. Kazi, Xiangyu Guo, Ryan Zvanut, Chabum Lee, Bruce L. Tai
Summary: This study investigates the issues in machining additively manufactured metals and identifies the causes as material inhomogeneity, porosity, and thermal stress induced by the process. The results show that additively manufactured metals are more difficult to machine and can cause premature tool failure or surface roughness. Heat treatment can eliminate the issues related to material inhomogeneity and porosity, but there is no significant difference in surface finish under the current cutting conditions.
Article
Materials Science, Multidisciplinary
J. Chen, D. Fabijanic, M. Brandt, Y. Zhao, S. B. Ren, W. Xu
Summary: This study demonstrates the development of a near-equiaxed α microstructure in situ via dynamic globularization in the as-built state of LPBF Ti-6Al-4V for the first time. The globularization process during LPBF is governed by mechanisms such as sub-grain boundary formation, boundary splitting, thermal grooving, lamellar termination migration and epitaxial growth. These findings provide new knowledge towards a holistic microstructural control strategy in additively manufactured Ti-6Al-4V.
Article
Chemistry, Physical
Terrence P. Moran, Patricio E. Carrion, Seungjong Lee, Nima Shamsaei, Nam Phan, Derek H. Warner
Summary: This study investigates the efficacy of hot isostatic pressing (HIP) in enhancing the fatigue performance of additively manufactured (AM) Ti-6Al-4V. The limitations of HIP are explored by varying the initial material state through the selection of AM system, powder chemical composition, and process parameters. It is found that the fatigue performance of HIP'd AM Ti-6Al-4V depends on the as-built quality, and differences in common material attributes cannot fully explain the observed discrepancies in performance. Furthermore, exploring HIP parameters outside of ASTM recommendations shows that a reduced temperature and high-pressure treatment significantly improve fatigue performance.
Article
Materials Science, Multidisciplinary
Lara Draelos-Hagerty, James D. Paramore, Brady G. Butler, Peeyush Nandwana, Ankit Srivastava
Summary: This article presents a thermohydrogen post-process treatment that can achieve equiaxed grain morphology in EBM-processed Ti-6Al-4V without sacrificing mechanical properties.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2023)
Article
Chemistry, Physical
Yifei Zhang, Limin Feng, Tao Zhang, Haoyuan Xu, Jianzhong Li
Summary: Research showed that AM Ti-6Al-4V annealed at 940 degrees C exhibited stronger corrosion resistance, while Ti-6Al-4V alloy with aging treatment had a higher corrosion rate. The variations in phase content and texture were identified as the main factors affecting the corrosion resistance of Ti-6Al-4V alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Manufacturing
Seong Je Park, Jun Hak Lee, Jeongho Yang, Woongbeom Heogh, Dongseok Kang, Si Mo Yeon, Sang Hoon Kim, Sukjoon Hong, Yong Son, Jiyong Park
Summary: A lightweight injection mold consisting of lattice structures was designed and fabricated using additive manufacturing technology. The weight and material cost of the mold were significantly reduced, and successful injection tests were conducted using polyvinyl chloride (PVC) without causing damage to the mold.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Engineering, Biomedical
Saurabh Kumar Gupta, Nagur Shahidsha, Sumit Bahl, Dhaval Kedaria, Sarat Singamneni, Prasad K. D. Yarlagadda, Satyam Suwas, Kaushik Chatterjee
Summary: By utilizing selective laser melting (SLM) and tailored heat treatment, it is possible to improve the ductility of additively manufactured bone plates, making them comparable to those made from wrought alloy. This has important implications for the fabrication of patient-specific metallic orthopedic devices without compromising their biomechanical performance.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2021)
Article
Automation & Control Systems
J. Rebelo Kornmeier, M. Hofmann, W. M. Gan, V Robin, F. Valiorgue, H. Pascal, J. Gibmeier, J. Saroun
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2020)
Article
Nanoscience & Nanotechnology
J. Rebelo Kornmeier, M. Hofmann, J. Gibmeier, C. E. Truman
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2020)
Article
Materials Science, Multidisciplinary
Pierre-Antoine Dubos, Jamal Fajoui, Nadjib Iskounen, Michel Coret, Saurabh Kabra, Joe Kelleher, Baptiste Girault, David Gloaguen
Article
Materials Science, Multidisciplinary
Nadjib Iskounen, Pierre-Antoine Dubos, Jamal Fajoui, Michel Coret, Marie-Jose Moya, Baptiste Girault, Nicolas Barrier, Nicolas Bruzy, Eric Hug, David Gloaguen
Summary: The allotropic phase transformation in polycrystalline high-purity cobalt is incompletely reversible and is induced by plastic deformation, leading to the presence of a metastable phase at room temperature and altering the mechanical properties. The transformation is initiated by basal slip mechanisms and competes with twinning mechanisms during the second work-hardening stage.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Eric Hug, Clement Keller, Pierre-Antoine Dubos, Mayerling Martinez Celis
Summary: This study explores the mechanical properties of cobalt under different grain sizes, revealing significant effects of the thickness-to-grain size ratio on yield stress and work hardening. The presence of a multicrystalline regime is highlighted for lower thickness values, while almost single crystalline behavior is observed for larger thicknesses. The influence of twinning on dislocation glide and surface effects is also discussed, showing the gradual disappearance of size effects with hardening.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Instruments & Instrumentation
R. S. Ramadhan, S. Cabeza, T. Pirling, S. Kabra, M. Hofmann, J. Rebelo Kornmeier, A. M. Venter, D. Marais
Summary: Positional accuracy is a crucial parameter in neutron diffraction residual stress investigations, requiring precise measurements of strains at localized positions along multiple sample orientations. A standardized approach has been developed for quantitative analysis of positional accuracy on neutron strain scanners, using specific sample sets with geometries for assessment of alignment procedures and accuracies. The method has been implemented on four instruments to achieve comparable performance with positional accuracies around 100 µm, confirming the high precision attainable for non-destructive stress determination.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
(2021)
Article
Materials Science, Multidisciplinary
Quentin Hatte, Mireille Richard-Plouet, Pierre-Yves Jouan, Pascal Casari, Pierre-Antoine Dubos
Summary: This study presents a simple and versatile analytical method for characterizing residual stress associated with coating deposition processes. The results show that both coatings studied have a low level of residual stress, which is beneficial for anti-corrosion applications.
Article
Chemistry, Physical
Samuel Pulvermacher, Tobias Buecker, Jan Saroun, Joana Rebelo-Kornmeier, Michael Hofmann, Jens Gibmeier
Summary: Experimental analyses of phase-specific residual stresses after deep rolling were conducted using laboratory X-ray diffraction and neutron diffraction. The results show that neutron diffraction can non-destructively determine meaningful macro residual stress depth distributions, and corrections for instrumental surface effects through neutron ray-tracing simulation are applicable to multiphase materials.
Article
Nanoscience & Nanotechnology
Kodjo Emmanuel Agbovi, Baptiste Girault, Jamal Fajoui, Saurabh Kabra, Winfried Kockelmann, Thomas Buslaps, Agnieszka Poulain, David Gloaguen
Summary: Neutron and high-energy X-ray diffraction methods were used to investigate deformation mechanisms during uniaxial tensile tests of Grade 1 commercially pure titanium. Results showed good agreement between simulations and experimental data, and the EPSC model accurately predicted lattice strains, grain reorientation, and macroscopic stress-strain response. Study on two different textured products evaluated the influence of texture on mesoscopic and macroscopic responses of Ti-alpha alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Joana Rebelo-Kornmeier, Maria Jose Marques, Weimin Gan, Antonio Castanhola Batista, Sanjooram Paddea, Altino Loureiro
Summary: This study analyzes the effect of heat treatment on the residual stresses of welded cladded steel samples. The results show that heat treatment at a higher temperature can reduce more than 50% of the initial residual stress values, with the advantage of shorter time and greater economic feasibility.
Article
Materials Science, Multidisciplinary
Pierre-Antoine Dubos, Ameni Zaouali, Pierre-Yves Jouan, Mireille Richard-Plouet, Valerie Brien, David Gloaguen, Baptiste Girault
Summary: In this study, uniaxial tensile tests were conducted on nickel sheets with few grains across the thickness. It was found that surface treatment can significantly improve the mechanical performances of the nickel sheets by blocking dislocation movement.
MATERIALS LETTERS-X
(2022)
Article
Materials Science, Multidisciplinary
Kodjo Emmanuel Agbovi, Baptiste Girault, Jamal Fajoui, Saurabh Kabra, Winfried Kockelmann, Pierre-Antoine Dubos, David Gloaguen
Summary: The plastic deformation of titanium alloys is influenced by temperature and mechanical loading. Slip and twinning systems are involved in the process. However, it is not clear which deformation modes are activated in the polycrystal during loading, especially with temperature changes. Neutron diffraction measurements were conducted to analyze the intergranular strain evolution under tensile tests at different temperatures. Different scales of characterization were used to obtain information about the deformation mechanisms governing the material's behavior. An elastoplastic self-consistent approach was used to interpret the experimental observations. The study successfully predicted the macroscopic behavior and lattice strain development.
