Review
Engineering, Mechanical
Renangi Sandeep, Arivazhagan Natarajan
Summary: This article provides an extensive review on thermal joining technologies for hybrid structures of CFRP and metals, including laser welding, friction-based welding technologies, ultrasonic welding, and induction welding processes. It also presents additive manufacturing-based techniques for fabricating hybrid structures. The article primarily focuses on the current knowledge, process development, and future improvements of these joining technologies.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING
(2022)
Article
Engineering, Mechanical
Silvia Cecchel, Nima Razavi, Francesco Mega, Giovanna Cornacchia, Andrea Avanzini, Davide Battini, Filippo Berto
Summary: A first assessment of product durability was conducted on an SLM Ti6Al4V conrod with a lightweighted structure. Full-scale fatigue testing and finite element analyses were performed to determine stress cycles in critical regions. End of life (EOL) and metallurgical analysis were also conducted. The study obtained a fatigue diagram covering the finite life and estimating the infinite life load levels, which is significant for the fatigue assessment of additive manufacturing (AM) components. The fatigue life of the SLM conrod was found to be lower than the conventional one, but the EOL analysis indicated potential future improvements.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Anastasios G. Gavras, Anthony G. Spangenberger, Diana A. Lados
Summary: A study was conducted on the long and small fatigue crack growth mechanisms of various light structural aluminum and titanium alloys, leading to the development of a predictive model for microstructurally controlled small fatigue crack growth behavior, which agrees well with experimental data.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Xavier Lesperance, Paul Ilie, Ayhan Ince
Summary: This study investigates the long fatigue life characteristics of AlSi10Mg and AlSi7Mg aluminium alloys produced using direct metal laser sintering. The results of fatigue tests suggest that the effects of heat treatment on high cycle fatigue and very high cycle fatigue performance of additive manufacturing alloys should be further explored in the context of microstructural changes.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2021)
Article
Nuclear Science & Technology
D. Dorow-Gerspach, M. Bram, V. Ganesh, J. Matejicek, G. Pintsuk, M. Vilemova, M. Wirtz, C. Linsmeier
Summary: The joining of tungsten and steel is crucial for future commercial fusion reactors, but the large difference in their coefficient of thermal expansion can lead to high thermal stresses and premature failure of the joint. Two solutions explored in this study are the use of functionally graded materials with varying thermal expansion coefficients and the insertion of a ductile metal interlayer. Different joining technologies were evaluated through high heat flux benchmark tests.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Engineering, Manufacturing
G. Buffa, L. Fratini, U. La Commare, D. Roemisch, S. Wiesenmayer, S. Wituschek, M. Merklein
Summary: The increasingly demanding needs of emissions and costs reduction in the transportation industry are driving engineers to use lighter structures. It has been found that conventional fusion welding processes are inadequate for joining complex structures, thus joining by forming technologies are considered a better option. Over the past 25 years, several forming processes that can effectively join virtually every structural material have been developed.
INTERNATIONAL JOURNAL OF MATERIAL FORMING
(2022)
Review
Chemistry, Physical
Andrea Karen Persons, John E. Ball, Charles Freeman, David M. Macias, Chartrisa LaShan Simpson, Brian K. Smith, Reuben F. Burch
Summary: Standards for fatigue testing of wearable sensors are lacking, leading to difficulties in direct comparisons and fatigue life predictions. Different material combinations and testing methodologies result in a variety of fatigue behaviors and life predictions for sensors.
Article
Engineering, Mechanical
Abdul Khadar Syed, Xiang Zhang, Armando Caballero, Muhammad Shamir, Stewart Williams
Summary: This study investigates the influence of two different deposition strategies on the tensile and high cycle fatigue properties of wire + arc additive manufactured Ti-6Al-4V alloy. The oscillation build had lower static strength but similar elongation values compared to the parallel pass build. Anisotropic elongation values were observed due to the presence of columnar primary 13 grains, with vertical samples showing higher elongation values parallel to the primary grains. Fatigue strength was comparable to wrought materials and greater than typical cast materials, with crack initiation mostly from pores and microstructural features in the samples.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Materials Science, Multidisciplinary
Amrit Raj Paul, Avinash Mishra, Manidipto Mukherjee, Dilpreet Singh
Summary: This paper investigates the microstructure and mechanical properties of SS-Al dissimilar joints formed by Al2O3 interfacial doping in a wire arc direct energy deposition process with varying heat input. The results show that Al2O3 has a significant effect on grain refinement, and the presence of FeAl, FeAl3, and Fe2Al5 at the interface increases with increasing heat input. The presence of Al2O3 and intermetallic compounds improves the interfacial strength.
Article
Materials Science, Multidisciplinary
Yali Yang, Hao Chen, Jiwen Li, Wei Liu, Xuefei Shi, Qiuwei He, Yujie Liu, Jie Shen
Summary: This study focuses on the fatigue damage of critical components and structures, and proposes a new multiscale fatigue damage index and an incremental evaluation method for fatigue damage. Experimental results show that this index performs significantly better than existing techniques in terms of correlation with actual fatigue life, and it can be used for nondestructive inspection and evaluation of defects and damage in material manufacturing processes.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2022)
Review
Materials Science, Multidisciplinary
Reza Motallebi, Zeinab Savaedi, Hamed Mirzadeh
Summary: Additive manufactured magnesium alloys have wide applications in the medical and automotive industries. However, the printability of these alloys is challenging and often results in various defects. This overview article critically discusses recent advances in hot isostatic pressing, solution annealing, and aging/precipitation heat treatment for improving the microstructure and mechanical/functional properties of magnesium alloys.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
Dingcheng Tang, Xiaofan He, Bin Wu, Linwei Dang, Hao Xin, Yuhai Li
Summary: This paper investigates the effects of build orientation on the anisotropic fatigue performance of DED Ti-6Al-4V, and reveals through fatigue tests and microstructure analysis that crystallographic orientation and α colony are the key factors causing the anisotropy induced by build orientation.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Manufacturing
Yansong Zhang, Huaming Wang, Yanyan Zhu, Shuquan Zhang, Fang Cheng, Junwei Yang, Bing Su, Chen Yang
Summary: Lightweight refractory high-entropy alloys (LRHEAs) have lower density and better ductility compared to other refractory high-entropy alloys. Laser directed energy deposition additive manufacturing (LDED) technology is an ideal process for preparing LRHEAs. This study investigated the microstructure evolution and the plastic deformation mechanisms of a new LRHEA Al0.3NbTi3VZr1.5 fabricated by LDED.
ADDITIVE MANUFACTURING
(2023)
Article
Engineering, Mechanical
I. J. Wietecha-Reiman, A. Segall, X. Zhao, T. A. Palmer
Summary: A tool based on fractal and topological techniques using image analysis has been developed to accurately characterize fracture modes and crack initiation locations. This tool quantifies feature complexity, heterogeneity, and connectivity through fractal dimensions, lacunarity, and topology measurements. It was validated on complex fatigue fractures in Ti-6Al-4V, easily differentiating fracture initiation sites and fracture modes.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
B. Fernandez Silva, J. Kawalko, K. Muszka, M. Jackson, K. Fox, B. P. Wynne
Summary: This paper investigates the formation and deformation mechanisms of quasi-cleavage facets in dwell fatigue in a bimodal titanium alloy. It identifies basal slip as the critical damage mode leading to dwell fatigue failure and presents a possible criterion for slip transfer.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Biomedical
Nils Wegner, Martin Klein, Ronja Scholz, Daniel Kotzem, Marina Macias Barrientos, Frank Walther
Summary: Different implant materials have been used for decades to reconstruct damaged tissues, aiming to improve patient's quality of life. Fatigue strength is a critical factor in implant performance, and inaccurate estimation can lead to unexpected early failure. Using short-time testing methods can significantly reduce the number of tests needed to determine fatigue strength, providing a more efficient and application-oriented approach for selecting suitable implant materials.
JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS
(2022)
Article
Chemistry, Physical
Michael P. Milz, Andreas Wirtz, Mohamed Abdulgader, Dirk Biermann, Wolfgang Tillmann, Frank Walther
Summary: This study investigates the effect of twin wire arc spraying and machine hammer peening (MHP) post-treatment on the fatigue behavior of ZnAl4 coatings. The study found that in the high cycle fatigue regime, the additional MHP post-treatment can improve the lifetime of the coating.
Article
Materials Science, Multidisciplinary
Juliane Moritz, Mirko Teschke, Axel Marquardt, Stefan Heinze, Mirko Heckert, Lukas Stepien, Elena Lopez, Frank Brueckner, Frank Walther, Christoph Leyens
Summary: This study investigates the effects of hot isostatic pressing (HIP) and subsequent two-step heat treatments on the microstructure and mechanical properties of titanium aluminide alloy fabricated via electron beam powder bed fusion (PBF-EB/M). The highest ultimate tensile strength is achieved after HIP due to the elimination of lack-of-fusion defects. Challenges originating from the PBF-EB/M process, such as local variations in chemical composition due to aluminum evaporation, affect the microstructures after heat treatment.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Juliane Moritz, Mirko Teschke, Axel Marquardt, Lukas Stepien, Elena Lopez, Frank Brueckner, Frank Walther, Christoph Leyens
Summary: This study investigates the influence of process parameters and heat treatments on the microstructure and defect distribution of Ti-43.5Al-4Nb-1Mo-0.1B (TNM-B1) samples produced by electron beam powder bed fusion (PBF-EB/M). By adjusting the volumetric energy densities during the PBF-EB/M process, the aluminum content in the additively manufactured samples was deliberately controlled. The results show that the microstructure after heat treatment is strongly dependent on the PBF-EB/M parameters and the associated aluminum evaporation. It is possible to produce locally adapted microstructures within one component by varying the process parameters and subsequent heat treatment.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Nagarjuna Remalli, Mathias Munch, Mohsin Hasan, K. Nanda Kishore, Felix Stern, Nikolas Baak, Frank Walther, Manjini Sambandam, Steffen Klapprott, Koteswararao Rajulapati, Robert Brandt
Summary: Despite the well-known fact of low temperature creep deformation in high strength steels, its rate controlling mechanism remains unclear. This study experimentally validates the exhaustion creep model for low temperature creep behavior in SAE 9254 spring steel and proposes a hypothesis that dislocation glide in the retained austenite phase predominantly contributes to low temperature creep strain. The reduction in creep rate with time is attributed to the exhaustion of this deformation mechanism by strain-induced martensitic transformation.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Automation & Control Systems
Lukas Kersting, Bahman Arian, Julian Rozo Vasquez, Ansgar Traechtler, Werner Homberg, Frank Walther
Summary: The automated and resource-efficient production of high-strength lightweight components is becoming more important in industries such as aircraft or vehicle construction. The conventional flow-forming process has limitations in terms of reproducibility and producing parts with well-defined material property distributions. A novel closed-loop property control system that manipulates the tool path of the flow forming actuator based on online property measurement during the process could enhance the manufacturing process. This paper presents a control system model for the flow-forming process of metastable austenitic stainless steel.
AT-AUTOMATISIERUNGSTECHNIK
(2023)
Article
Engineering, Mechanical
Jochen Tenkamp, Bastian Blinn, Tilmann Beck, Frank Walther
Summary: This study analyzed the microstructure and fatigue properties of precipitation hardening Al-Si cast alloys, and investigated the influence of various factors on fatigue behavior and fatigue damage tolerance. It was found that sand castings exhibited better fatigue properties and damage tolerance compared to die castings.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Materials Science, Composites
Selim Mrzljak, Benjamin Zanghellini, Lars Gerdes, Ramon Helwing, Reinhard Schuller, Gerhard Sinn, Helga Lichtenegger, Frank Walther, Harald Rennhofer
Summary: Nano-reinforcements have been shown to enhance the mechanical properties of CFRP, both in quasi-static and fatigue load conditions, and are a promising option for optimizing CFRP performance. However, the use of alignment techniques for oriented nano-reinforcements is still insufficiently studied. This research investigates the influence of oriented carbon nanofibres (CNF) on the mechanical properties of bidirectional CFRP.
JOURNAL OF COMPOSITE MATERIALS
(2023)
Article
Chemistry, Physical
Chengsong Cui, Felix Stern, Nils Ellendt, Volker Uhlenwinkel, Matthias Steinbacher, Jochen Tenkamp, Frank Walther, Rainer Fechte-Heinen
Summary: In this study, the researchers developed duplex stainless steel powders through atomization with different process gases and temperatures. Nitrogen-atomized powders showed higher nitrogen content while argon-atomized powders exhibited more gas porosity. Higher atomization gas temperatures resulted in finer powder particles. The duplex stainless steel powders demonstrated good processability in laser powder bed fusion.
Article
Materials Science, Multidisciplinary
Daniel Kotzem, Tizian Arold, Kevin Bleicher, Rajevan Raveendran, Thomas Niendorf, Frank Walther
Summary: Powder bed fusion (PBF) processes allow for the efficient manufacturing of complex components. This study focuses on lattice structures with varying mechanical properties and aims to understand the complex process-structure-property relationships in order to implement PBF manufactured lattice structures in safety-relevant applications. Ti6Al4V lattice structures with different lattice types (BCC and F2CCZ) were manufactured and evaluated in terms of microstructural features and mechanical behavior. Different in-situ measurement techniques were employed to analyze damage progression under quasi-static and cyclic loading.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Juliane Moritz, Mirko Teschke, Axel Marquardt, Lukas Stepien, Elena Lopez, Frank Brueckner, Frank Walther, Christoph Leyens
Summary: In powder bed fusion additive manufacturing, the commonly used parameter E-V may not be suitable as a design parameter, as different contributing parameters can affect part properties. This study systematically varied beam current, scan velocity, and line offset in electron beam powder bed fusion (PBF-EB) while maintaining a constant E-V for TNM-B1 alloy. The results showed that individual parameters, such as low beam currents, low-to-intermediate scan velocities, and low line offsets, were important for achieving even surfaces, high relative densities, and homogeneous microstructures.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Characterization & Testing
Yashar Sarafraz, Malte Brink, Nikolas Baak, Alexander Koch, Frank Walther
Summary: The micromagnetic Barkhausen noise was used as a nondestructive testing method to analyze the fatigue behavior of high-strength steels. The micromagnetic Barkhausen noise energy (MBNEnergy) was measured and correlated with digital image correlation to investigate the effect of stress and strain on MBNEnergy. Different steels were studied, and an increase in MBNEnergy was observed for the bainite phase steel 18MnCrMoV6, while no significant increase or change was observed for the ferrite-pearlite steels 38MnVS6 and 46MnVS5.
Article
Materials Science, Multidisciplinary
Julian Rozo Vasquez, Bahman Arian, Lukas Kersting, Werner Homberg, Ansgar Traechtler, Frank Walther
Summary: This paper evaluates the suitability of X-ray diffraction technique in characterizing the phase transformation during the metal forming of metastable austenitic steel AISI 304L. The XRD peaks at specific 2θ diffraction angles provide information about the phase amount. Various characterization techniques were used to analyze the results and establish a correlation between XRD measurements and the amount of martensite phase. XRD was validated as a suitable technique for characterizing the phase transformation of metastable austenites.
Article
Engineering, Mechanical
Felix Stern, Louis Becker, Jochen Tenkamp, Johannes Boes, Jonathan Lentz, Sebastian Weber, Frank Walther
Summary: The impact of nitrogen alloying on corrosion and corrosion fatigue behavior of austenitic stainless steel AISI 316L processed via laser beam powder bed fusion (PBF-LB) was investigated. The nitrogen alloyed steel showed improved pitting corrosion and fatigue behavior. A fracture mechanical approach was used to analyze the fatigue data and identify the improved defect tolerance due to nitrogen alloying.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Chemistry, Physical
Mohammed Intishar Nur, Meetkumar Soni, Mustafa Awd, Frank Walther
Summary: This study investigates the impact of internal defects on the fatigue life of selectively laser-melted specimens and proposes a correction factor hypothesis to improve the prediction method. It provides insights into how internal defects and loading situations affect fatigue life.
