Article
Engineering, Mechanical
T. Vuherer, M. Milcic, S. Glodez, D. Milcic, L. Radovic, J. Kramberger
Summary: This study focuses on the fatigue and fracture behavior of Friction Stir Welded AA2024-T351 joints at different welding speeds. Experimental results show that a welding speed of 116 mm/min exhibits the highest resistance against crack extension.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Metallurgy & Metallurgical Engineering
Jyotirmaya Kar
Summary: The electron beam welding process was used to create dissimilar butt-joints of AA-6061 and AA-2024 sheets under different welding conditions. X-ray computed tomographic analysis revealed the presence of insidious welding defects, such as porosities and microcracks, in all joints. Varying the EBW welding conditions resulted in changes in porosity content, size, and distribution. Increasing welding speed reduced porosity content and pore volume fractions by 30%, while oscillating or double-side pass conditions led to a significant reduction (80-90%). Among the different oscillating beam patterns, the triangular pattern was found to be the most effective in reducing weld porosities, whereas the infinity pattern was unsuitable for joining aluminum alloys.
WELDING IN THE WORLD
(2023)
Article
Materials Science, Multidisciplinary
Rasoul Khajeh, Hamid Reza Jafarian, Seyed Hossein Seyedein, Reza Jabraeili, Ali Reza Eivani, Nokeun Park, Yejin Kim, Akbar Heidarzadeh
Summary: The study investigated the effect of FSW parameters on the properties of 2024 aluminum alloy and copper joints, finding that the W/V ratio plays a significant role in determining the joints' characteristics. Optimal FSW conditions led to higher strength and ductility, as well as lower electrical resistivity.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Engineering, Civil
Yiang Li, Yang Li, Zeguang Liu, Yuanduo Yang, Sansan Ao, Zhen Luo
Summary: This paper examines the effect of mesh size on the lap-shear failure load, cross-sectional microstructure, and fracture morphology in the joining of carbon fiber reinforced PA66 composite using stainless steel mesh as energy director. The results indicate that mesh size plays an important role in weld formation and joint mechanical property. Optimum joint strength can be achieved with energy directors having large wire spacing, small wire diameter, and small area. Under appropriate welding energy and mesh size, the failure loads of joints exceed 10000 N, with the failure model being workpiece fracture.
THIN-WALLED STRUCTURES
(2023)
Article
Metallurgy & Metallurgical Engineering
Xian-ming Cheng, Ke Yang, Si-zhan Liu, Shan-lin Ji, Jian Wang
Summary: Ultrasonic welding experiments were conducted on Cu-Al cable joints with different parameters, and the results showed that the joints exhibited excellent mechanical properties and prevented the formation of intermetallic compounds under certain welding conditions.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2023)
Article
Polymer Science
Yuanduo Yang, Zhiwei Liu, Yuefang Wang, Yang Li
Summary: This paper numerically analyzes the contact behavior and temperature characterization during ultrasonic plastic welding using the harmonic balance method. The results show that amplitude and welding time are important factors determining the interface temperature, while plunging speed and trigger force have little effect. Furthermore, the study reveals that the heat generation mechanism changes during different stages of welding.
Article
Chemistry, Physical
Peng Yin, Chunguang Xu, Qinxue Pan, Wenjun Zhang, Xiaowei Jiang
Summary: This paper studied the effect of different ultrasonic power on the properties of welded joints during the welding of homogeneous armor steel. It found that ultrasonic welding can increase the weld depth and the width of the heat-affected zone (HAZ) on either side of the weld, and appropriate ultrasonic power can significantly improve the grain state of the weld. The microhardness, tensile strength, and impact resistance of the weld and HAZ vary with the ultrasonic power level.
Article
Metallurgy & Metallurgical Engineering
Peng-liang Niu, Wen-ya LI, Yu-hua Chen, Qi-peng Liu, Dao-lun Chen
Summary: The location of the base material has little effect on the tensile properties of the joints, but significant impact on the exfoliation corrosion performance. By optimizing the base material location, dissimilar joints with superior exfoliation corrosion resistance can be achieved.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2022)
Article
Materials Science, Multidisciplinary
Xuekuan Li, Tianyi Zhang, Shuang Li, Hansong Liu, Yan Zhao, Kai Wang
Summary: The study revealed that joints with lower cooling rates exhibited better mechanical properties, higher crystallinity, and more pronounced transcrystallinity. Stainless steel wires in the HEs acted as nucleating agents, promoting high-density nucleation sites and accelerating transcrystallinity formation at lower cooling rates.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Nanoscience & Nanotechnology
Jialiang Dong, Datong Zhang, Weiwen Zhang, Genghua Cao, Cheng Qiu
Summary: The combination of water-cooling and post-weld heat treatment (PWHT) was found to be an efficient method to greatly improve the strength of underwater friction stir welded joints of 7003/6060 aluminium alloys. The improvement in strength is attributed to the reprecipitation of high density beta phase. Direct artificial aging (AA) after welding can further increase the joint strength, but it deteriorates the elongation. The grain size plays a minor role in the mechanical properties of the dissimilar joints.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Z. L. Ni, Y. Liu, F. X. Ye
Summary: By adding a Cu nanoparticles interlayer between two Cu sheets, the mechanical properties and electrical resistance of ultrasonic spot welded Cu/Cu joints can be improved. The addition of the Cu nanoparticles interlayer promotes the formation of metallurgical bonding and reduces the size of the grains, resulting in enhanced bonding strength and reduced electrical resistance. The optimal welding time for the Cu/Cu NPs/Cu joint is found to be 0.8 seconds.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Pengliang Niu, Wenya Li, Chenggang Yang, Yuhua Chen, Daolun Chen
Summary: Low cycle fatigue tests were conducted on friction stir welded dissimilar aluminum alloy joints with different strain amplitudes, revealing that the positioning of base materials during FSW affected the fatigue resistance of joints. When 7075 aluminum alloy was placed on the advancing side, longer fatigue life was achieved. Fracture of fatigued specimens always occurred at the softer heat-affected zone on the 2024 side, with crack initiation from the specimen surface and crack propagation characterized by typical fatigue striations.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Wei Feng, Jian Zhang, Jun Gao, Yong Xiao, Guoqiang Luo, Qiang Shen
Summary: Aluminum and titanium alloy joints were successfully fabricated by ultrasonic welding, and the interface microstructure and mechanical properties of the Al/Ti joint were investigated. A relatively sufficient metallurgical bonding was achieved at a welding time of 0.3 s, resulting in a transformation of the fracture pattern from interfacial failure to nugget pull-out failure. The maximum lap shear load reached 3650 N. EBSD analysis revealed that dynamic recrystallization mainly occurred at the interface of the Al side due to severe plastic deformation and heat generation.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Zilong Peng, Taoshuai Zhou, Yinan Li, Zhuang Cui, Zhiyuan Wu, Jiuchun Yan
Summary: A novel combination of multi-interlayers composed of Ni, Al, and Zn foil was used to join dissimilar alloys, resulting in enhanced shear strength and improved mechanical performance. The Al interlayer played a crucial role in forming mixed IMCs layer, enhancing bonding between Ni interlayer and AZ31.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
Yumeng Sun, Wei Liu, Yupeng Li, Wenbiao Gong, Chuan Ju
Summary: The study investigated the effect of different shapes of tool pins on the plastic flow of 2024-T6 aluminum alloy during friction stir welding. It was found that the conical cam thread tool pin had the strongest ability to drive metal downward and the best metal fluidity, leading to excellent joint formation with an onion ring pattern. Overall, the joints showed good mechanical properties and fracture morphology, with plastic fracture being the dominant mode of failure.
Article
Chemistry, Physical
Selim Mrzljak, Maik Trautmann, Guntram Wagner, Frank Walther
Article
Materials Science, Multidisciplinary
Marco Thomae, Andreas Gester, Guntram Wagner, Marco Fritzsche
Article
Materials Science, Multidisciplinary
Vasilii Fedorov, Thomas Uhlig, Harry Podlesak, Guntram Wagner
Article
Materials Science, Multidisciplinary
Vasilii Fedorov, Thomas Uhlig, Guntram Wagner
Summary: The study explored the relationship between the microstructure of the reaction zone and mechanical properties in brazed joints of aluminum alloy 3003 and stainless steel AISI 304. It was found that an appropriate thickness of the reaction zone is beneficial for the mechanical properties of the joints, while high temperature aging results in an increase in reaction zone thickness and growth of intermetallic layers, leading to a decrease in the tensile shear strength of the joints.
Article
Materials Science, Multidisciplinary
Holger Schwarz, Thomas Uhlig, Niels Roesch, Thomas Lindner, Fabian Ganss, Olav Hellwig, Thomas Lampke, Guntram Wagner, Thomas Seyller
Summary: This study analyzed thin films deposited via magnetron sputtering from two different preparation methods of CoCrFeNi High-Entropy Alloy targets and found that their stoichiometry, phase composition, and microscopic structure were almost identical after film deposition with the same parameters.
Article
Chemistry, Analytical
Dhivakar Rajendran, Rajarajan Ramalingame, Saravanan Palaniyappan, Guntram Wagner, Olfa Kanoun
Summary: In this study, flexible and low-cost pressure sensors based on MWCNT/PDMS were designed for foot pressure monitoring. The sensors showed stable response, high sensitivity, and low hysteresis effect. Experimental results demonstrated repeatable responses under different pressure loading rates, showcasing the sensors' potential for accurately measuring foot pressure distribution during activities like walking and standing.
Article
Materials Science, Multidisciplinary
Saravanan Palaniyappan, Maik Trautmann, Yiran Mao, Johann Riesch, Parikshith Gowda, Nick Rudolph, Jan Willem Coenen, Rudolf Neu, Guntram Wagner
Summary: Research on tungsten fiber-reinforced tungsten (W-f/W) composites has shown that the quality of yttria coatings on tungsten wires, deposited through PVD and CVD techniques, is influenced by factors such as temperature, growth rate, and oxidation of W-f. Comparatively, PVD is more effective in reducing the oxidation of W-f compared to the formation of WO3 in high-temperature CVD coatings. The microstructure, phase, and chemical composition of yttria-coated tungsten fibers are comprehensively characterized using SEM, XRD, and Raman spectroscopy techniques.
Article
Materials Science, Multidisciplinary
Toni Sprigode, Andreas Gester, Guntram Wagner, Thomas Mader, Bjorn Senf, Welf-Guntram Drossel
Summary: In this study, NiTiCu shape memory alloy wires were joined with silver-coated copper ferrules via ultrasonic spot welding, with tensile tests showing that the ultimate tensile strengths of the joints reached almost 100% of the base material. The ultrasonic welding process did not affect the transition temperatures of the shape memory alloy.
Article
Materials Science, Multidisciplinary
Alexander Ivannikov, Vasilii Fedorov, Anton Abramov, Milena Penyaz, Diana Bachurina, Thomas Uhlig, Alexey Suchkov, Guntram Wagner, Pavel Morokhov, Oleg Sevryukov
Summary: This study investigated aluminum alloys based on the Al-Ge-Si system with a high germanium content for brazing aluminum alloy AA6082 with stainless steel AISI 304, analyzing temperature characteristics, microstructural, and mechanical properties of the filler alloys. The results show that increasing germanium content leads to a decrease in liquidus temperature, the alloys exhibit a homogeneous structure, and an increase in germanium content results in separation and more faceted solid solution particles. Nanohardness measurements revealed variations in hardness values among different solid solutions, with implications for predicting seam structure after brazing.
Article
Materials Science, Multidisciplinary
Marco Thomae, Guntram Wagner
Summary: Manufacturing advanced high-strength steels with enhanced ductility is a persistent research goal, with the development of quenching and partitioning heat treatment processes to adjust material properties and improve tensile strength and ductility. The study found that the quenching and partitioning treatment significantly influenced the microstructure and mechanical properties of the steel, with different heat treatment conditions resulting in varied microstructures and tensile strengths.
Article
Materials Science, Multidisciplinary
Holger Schwarz, Thomas Uhlig, Thomas Lindner, Thomas Lampke, Guntram Wagner, Thomas Seyller
Summary: The hardness of the CoCrFeNi high-entropy alloy (HEA) is systematically enhanced by the addition of tungsten carbide (WC). The increase in WC content in the fabricated thin films through magnetron sputtering results in an increase in hardness.
Article
Chemistry, Physical
Maik Trautmann, Husam Ahmad, Guntram Wagner
Summary: High-energy ball milling is an efficient method for producing composite powders with ceramic particles dispersed in a metallic matrix. However, the resulting composite powders often have irregular shapes due to collision events and plastic deformations during milling. This study investigates different approaches, including milling process parameters and post-treatments, to influence particle shape. It is found that milling with menthol as a process control agent leads to the finest composite powder, while mechanical post-treatment does not improve particle roundness. Thermal spraying and heat treatment also result in significant changes in the shape of the composite powders.
Article
Materials Science, Multidisciplinary
Saravanan Palaniyappan, Andreas Todt, Maik Trautmann, Felix Roeder, Carolin Binotsch, Birgit Awiszus, Guntram Wagner
Summary: This research focuses on generating a graded property transition at the interface of metal-plastic joints by brazing a 3D transition wire structure (TWS) before being molded with plastic using an injection over-molding process. The graded steel wire structures with different carbon content were brazed onto galvanized steel sheets using the hotplate brazing technique and electroplated zinc coatings were used to improve the brazing quality. The resulting brazed joints were evaluated for their microstructural, mechanical, and intermetallic phase characteristics.
Article
Chemistry, Multidisciplinary
Benjamin Sattler, Susann Hausner, Guntram Wagner
Summary: By using Ni nanoparticles, high shear strengths can be achieved in the bonding of Ni base superalloys at comparatively low temperatures. The size and composition of the nanoparticles significantly influence the achievable strengths, with the temperature exerting the most influence.
Article
Materials Science, Multidisciplinary
Maik Trautmann, Selim Mrzljak, Frank Walther, Guntram Wagner
