Publications
97 results found
Zhang R, Jiang J, Lin J, et al., 2023, Investigation of variability in apparent values of materials properties in thermo-mechanical uniaxial tensile tests on sheet metals, Journal of Manufacturing Processes, Vol: 101, Pages: 737-754, ISSN: 1526-6125
Thermo-mechanical uniaxial tensile testing is commonly carried out to characterise the mechanical properties of materials under conditions which mimic advanced industrial forming processes, such as hot stamping of steels and aluminium alloys, and to generate microstructures for metallographic investigation. However, in this type of testing, heat loss to the specimen grips can lead to nonuniform temperature distributions along the gauge length, resulting in challenges in determining absolute values of materials properties at the nominal temperature of interest. The present study investigates the effect of these nonuniform temperature distributions on the variability in the thermo-mechanical properties as measured in the tests, and in the microstructures of the tested specimens. For this purpose, uniaxial tensile tests on the boron steel 22MnB5 and aluminium alloy AA6082 were performed under hot stamping conditions using a Gleeble 3800 thermal-mechanical physical simulation system, in which the specimens were heated using resistance heating and the strain fields were measured using digital image correlation (DIC). The nonuniformity of the temperature distributions along the gauge length was quantified. Both the strains and the strain rates along the gauge length were then computed and the effects of factors such as pre-forming gauge length, post-forming gauge length and specimen design on the spatial distribution of strains and strain rates were investigated. The effects of these factors on the values of thermo-mechanical properties determined from the tests, such as the ductility and the ultimate tensile strength (UTS), were also analysed and quantified. This study reveals the variability in the apparent values of materials properties as determined by thermo-mechanical testing resulting from nonuniform temperature distributions, and provides experimental data for the development of new standards for thermo-mechanical tests in future.
Wang W, Balint DS, Shirzadi AA, et al., 2023, Imparted benefits on mechanical properties by achieving grain boundary migration across voids, Acta Materialia, Vol: 256, Pages: 1-12, ISSN: 1359-6454
Understanding the interaction of micro-voids and grain boundaries is critical to achieving superior mechanical properties for safety-critical parts. Micro-voids and grain boundaries may interact during advanced manufacturing processes such as sintering, additive manufacturing and diffusion bonding. Here, we show imparted benefits on mechanical properties by achieving grain boundary migration across voids. The micro-mechanisms and quantitative analysis of grain boundary migration on local deformation were studied by integrated in-situ EBSD/FSE and crystal plasticity finite element modelling. It is revealed that a migrated grain boundary does not alter the activated slip systems but precludes grain boundary-multislip interaction around interfacial voids to alleviate stress concentrations. The stress mitigation caused by grain boundary migration is almost the same as that caused by void closure under the example diffusion bonding thermal-mechanical process used in this study. This new understanding sheds light on the mechanistic link between GND hardening, grain boundary migration and the corresponding material tensile behaviour. It opens a new avenue for achieving superior mechanical properties for metallic parts with micro-defects such as those generated in diffusion-bonded, sintered and additive manufactured components.
Zhang K, Jiang J, 2023, Enhancement of plasticity in Mg-3Al-1Zn alloy at cryogenic temperature, Journal of Materials Research and Technology, Vol: 25, Pages: 7454-7459, ISSN: 2238-7854
Compression tests were conducted at room and cryogenic temperatures to investigate the lowtemperature plasticity in Mg-3Al-1Zn alloy. The strain to failure and fracture strength in Mg3Al-1Zn alloy increase by 21.4% and 51.6% from room to cryogenic temperature. Using aquasi-in-situ EBSD method, it is found that {10 1̅ 2} tension twins dominate at roomtemperature, while abundant (101̅2)-(011̅2) twin-twin interactions are observed at cryogenictemperature. Multiple slips, including pyramidal and basal slips, occur in twin-twin interactions,enhancing the strain to failure and flow stress at cryogenic temperature. The high dislocationdensity near twin-twin interactions boundaries would contribute to the high hardening rate andflow stress at cryogenic temperature. This work would provide a novel way to enhanceplasticity in magnesium alloys and gain an in-depth understanding of twin-twin interactions.
Sun F, Penchev P, Pruncu CI, et al., 2023, On enhancement of fracture resistance of adhesive joints by surface micropatterning using a femtosecond laser, Journal of Materials Processing Technology, Vol: 315, Pages: 1-12, ISSN: 0924-0136
This study focuses on the influence of surface micropatterns, including uniform and nonuniform grooves fabricated by selective removal of a designed volume from aluminum alloy substrates using a femtosecond laser, on the mode I fracture behavior of adhesively bonded interfaces. The morphology, wettability, chemistry and microstructure of the patterned surfaces have been analyzed. The mode I fracture behavior of adhesive joints was characterized by measuring the fracture resistance using a J-integral approach, and the fracture process in the joint was investigated numerically using a continuum damage model. The results show that the laser patterning has modified the surface roughness, wettability and surface chemistry such that the fracture resistance could be greatly increased. It also reveals the significance of patterning uniformity across the surfaces and the existence of a limiting effective patterning ratio (the ratio of the patterned area to the flat bonding area) on enhancing the fracture resistance. Local plastic deformation that occurred in the adhesive at the patterned structures due to stress concentration was found to be one toughening mechanism although it tended to induce crack growth close to one substrate-adhesive interface.
Huang Y, Jiang J, 2023, A Critical Review of von Mises Criterion for Compatible Deformation of Polycrystalline Materials, CRYSTALS, Vol: 13
Zhou X, Jiang J, Hu Z, et al., 2022, Lightweight Materials in Electric Vehicles, International Journal of Automotive Manufacturing and Materials, Pages: 3-3
<jats:p>ReviewLightweight Materials in Electric VehiclesXianyan Zhou 1,*, Jun Jiang 2, Zhili Hu 3, and Lin Hua 31 Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway 2 Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK3 School of Automotive Engineering, Wuhan University of Technology, Luoshi Road, Wuhan, 430070, China* Correspondence: xianyan.zhou@ntnu.no Received: 23 September 2022Accepted: 21 November 2022Published: 18 December 2022 Abstract: Lightweight materials are highly demanded in electric vehicles (EVs) to reduce environmental impacts and energy consumption. Aluminium alloys are promising materials in EVs due to their advantages such as high specific strength, corrosion resistance and recyclability. However, forming complex-shaped thin-wall aluminium products is challenging due to their poor formability and limited dimensional accuracy. Meanwhile, recycling some of the high-strength aluminium alloys from EVs is still challenging. This review highlights some of the future potential aluminium forming techniques for EV production, including incremental sheet forming (ISF), hot forming and quenching (HFQ ® ) technique, and transverse stretching and local bending (TSLB). Also, the issues associated with aluminium recycling are listed and discussed. This review provides scientific guidance to the industry and the scientific community for advancing the applications of aluminium alloys in EVs.</jats:p>
Liu Y, Zhang C, Wang Y, et al., 2022, Reveal the hot deformation behaviour and microstructure evolution in additively manufactured 316L stainless steel, Materials Science and Engineering: A, Vol: 861, Pages: 1-11, ISSN: 0921-5093
The novel hybrid manufacturing process incorporating additive manufacturing (AM) with a subsequent hot compression process has been proposed and applied to 316L stainless steel (316L SS). Compared to the conventional wrought 316L SS, the significantly coarser grain size was characterized in the directly AMed specimen, resulting in unacceptable mechanical properties as safety-critical parts. These coarse grains can be refined through the subsequent hot compression process. However, the detailed grain refinement process in these AMed materials has not been exploited. This motivates the study of the grain refinement of AM specimens through dynamic recrystallization (DRX) in hot compression. Hot compression was applied on AMed 316L SS specimens at temperatures from 800 °C to 1000 °C and different strain rates of 0.01 s−1, 0.1 s−1 and 1 s−1 by Gleeble. The results were compared with conventional wrought-annealed 316L SS specimens. To explain the flow stress behaviour, the underlying grain size, orientations, morphologies, and geometrically necessary dislocation (GND) density distribution and evolution were characterized by the electron backscatter diffraction (EBSD). The results suggest that the initial microstructure difference plays a dominant role in the flow stress response, and the DRX behaves very differently in these AMed and wrought-annealed specimens.
Jiang J, Lu Q, Zhang C, et al., 2022, Reveal the viscoplastic behaviour and microstructure evolution of stainless steel 316L, Materials, Vol: 15, ISSN: 1996-1944
Stainless steel 316L is a widely used structural material in the nuclear industry because of its excellent corrosion resistance and mechanical properties. However, very little research can be found on its viscoplastic behaviour and microstructure evolution at warm and hot deformation conditions, which hinder the possible application of advanced manufacturing technologies for producing complex parts, such as superplastic forming or hydroforming. The aims of this study are to explore stainless steel 316L’s viscoplastic behaviour, to determine its strain rate sensitivities, and to reveal its underlying microstructure evolution; this will allow appropriate manufacturing (forming) technologies and the optimal forming condition to be determined. Hence, isothermal tensile tests at 700 °C, 800 °C, 900 °C, and 1000 °C at strain rates of 0.01 s−1 and 0.001 s−1 have been conducted. Moreover, the corresponding microstructure evolution, including the grain orientation and geometrically necessary dislocation density, has been revealed by the electron backscatter diffraction method. The data show the viscoplastic behaviour of stainless steel 316L under various thermomechanical deformation conditions and how microstructure evolution influences the viscoplastic flow stress.
Cai W, Wang C, Sun C, et al., 2022, Investigation of Deformation Behavior of TWIP Steel Using Crystal Plasticity Coupling Temperature Effect, Jixie Gongcheng Xuebao/Journal of Mechanical Engineering, Vol: 58, Pages: 283-293, ISSN: 0577-6686
In order to investigate the deformation mechanism of TWIP steel at high temperature，the crystal plastic constitutive model was established by considering the effect of temperature on slip and twinning of TWIP steel，and the flow law and hardening law of considering temperature effect were proposed. The crystal plastic finite element model of TWIP steel during hot deformation was established by in-situ SEM high temperature tensile tests under 500 ℃ and 750 ℃. The stress-strain curves，strain hardening rates and twin volume fraction at different temperatures obtained by simulation were in agreement with the experimental results，which verified the correctness of the model. Based on the model，the effect of temperature on the slip，twinning and strain hardening of TWIP steel during plastic deformation was researched，the results show that the slip resistance，twinning resistance and strain hardening rate decrease unevenly with the increase of temperature，and the elongation after breaking decreases abnormally，from 53.4% at 25 ℃ to 16.5% at 750 ℃. With the increase of temperature，the twinning is restrained while the slip process is less affected by temperature，which shows the plastic deformation mechanism dominated by slip.
Zhou X, Sun C, Wang B, et al., 2022, Investigation and prediction of central cracking in cross wedge rolling, The International Journal of Advanced Manufacturing Technology, Vol: 123, Pages: 145-159, ISSN: 0268-3768
Central cracking refers to the formation of internal cavities in cross wedge rolling (CWR) products. It occurs in various materials such as aluminium/titanium alloys, steels and plasticine at room or elevated temperatures, driven by different central cracking mechanisms. However, these mechanisms are still elusive, and a unified central cracking predictive model is absent due to the complex stress states within the workpiece, including triaxial stress states, cyclic loading and severe shear effects. In this study, the underlying fracture mechanisms were revealed, and a robust unified damage model with sound physical meanings was developed using a lab-scale CWR physical model and finite element models. The physical model with the plasticine billets was built, allowing the CWR dies with different geometries rapidly 3D printed and the billets with various ductility efficiently manufactured. The central cracking transiting from brittle to ductile fracture was experimentally observed for the first time using specifically designed plasticine/flour composite samples at varying ductility. The corresponding physics-based central cracking predictive model was proposed and validated quantitatively with 60 groups of CWR tests and compared with ten existing damage models/fracture criteria. This study effectively solves the long-lasting central cracking problem in the CWR industry and enhances the scientific understanding of fracture mechanics in complex engineering applications.
Wang W, Politis NJ, Wang Y, et al., 2022, Solid-state hot forge bonding of aluminium-steel bimetallic gears: Deformation mechanisms, microstructure and mechanical properties, International Journal of Machine Tools and Manufacture, Vol: 180, ISSN: 0890-6955
Solid-state dissimilar bi- or multi-metallic bonding is promising for achieving lightweight or multifunctional components in automotive, nuclear power and aerospace industries. To understand how to achieve a high-quality bonding interface between dissimilar materials, aluminium alloy (Al)–steel (Fe) bimetal gears manufactured under hot forge bonding were systematically investigated. In this work, comprehensive analyses of forge bonding mechanics, microstructure features, bonding interface behaviours and resulting mechanical properties were undertaken using ex/in-situ experiments and finite element modelling. The results revealed that the bonding behaviour and microstructure evolution were significantly affected by the mechanical property mismatch between the two dissimilar workpieces (AA6082 and E355). This mismatch could be effectively adjusted by setting different forging temperatures. The interfacial bonding strengths of AA6082 and E355, manufactured at low and high temperatures, were observed to be governed by interdiffusion and oxide particles, respectively. Balancing interdiffusion and oxide breaking appears to be key to achieving optimized interface strength for dissimilar bimetallic forge bonding technology.
Wu Y, Tang Y, Zhang Y, et al., 2022, In situ radiographic study of the grain refining behavior of Al3Sc during the solidification of Al-10Cu alloy, Journal of Materials Science & Technology, Vol: 122, Pages: 33-43, ISSN: 1005-0302
Grain refinement of Al alloys inoculated by rare earth elements, such as Sc, has been extensively acknowledged, while the practical behavior of how inoculant Al3Sc particles affect the refinement in solidification has not been clarified due to the non-transparency of the solidification process. Here, the microstructural evolution of primary Al3Sc particles and α-Al grains in Al-10 wt.% Cu alloy solidifications with 0.2 wt.%, 0.6 wt.%, and 1.0 wt.% Sc additions was investigated by in situ synchrotron X-ray radiography. The detailed mechanisms of curve motion of grains (CMG) and melt convection were revealed. The efficient grains nucleation, uniformly scattered small initial grains, and long duration of melt convection contributed to the best refinement in the 0.6 wt.% Sc addition sample. This work provides a deep insight into grain refinement in solidification with Sc addition, which will enlighten the composition design and casting process of Al alloys inoculated by rare earth elements.
Imran SM, Li C, Lang L, et al., 2022, An investigation into Arrhenius type constitutive models to predict complex hot deformation behavior of TC4 alloy having bimodal microstructure, MATERIALS TODAY COMMUNICATIONS, Vol: 31
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- Citations: 1
Yasmeen T, Rahimi S, Hopper C, et al., 2022, Unravelling thermal-mechanical effects on microstructure evolution under superplastic forming conditions in a near alpha titanium alloy, Journal of Materials Research and Technology, Vol: 18, ISSN: 2238-7854
The superplastic formability of titanium alloys has been extensively exploited by various industries, especially for manufacturing of high value aerospace components. Material's microstructural characteristics, such as grain size and dislocations density, determine superplastic formability during manufacturing process and various constitutive relationships have been proposed to take their effects into consideration in modelling and simulation. However, most existing models do not include all these characteristics in their analyses due to the limitations in characterization techniques. This paper reports the results of a systematic study on the effects of thermal (i.e., static) and mechanical (i.e., dynamic) process parameters on the evolution of dislocations and microstructure, both independently and simultaneously, at superplastic forming regime. The evolution of microstructural phase fraction, grain size, crystallographic texture, and geometrically necessary dislocation (GND) density are investaged over a temperature range of 880–920 °C and under strain rates between 0.0005 and 0.01s−1. The results provide valuable insights into the microstructure evolution during superplastic forming on TA15 titanium alloy and form a basis for future physically based constitutive modelling.
Lu Q, Wu J, Liu S, et al., 2022, Revealing geometrically necessary dislocation density from electron backscatter patterns via multi-modal deep learning, ULTRAMICROSCOPY, Vol: 237, ISSN: 0304-3991
Mirza HA, Lang L, Tabasum MN, et al., 2022, An Investigation into the Forming of Fiber Metal Laminates with Different Thickness Metal Skins Using Hydromechanical Deep Drawing, APPLIED COMPOSITE MATERIALS, Vol: 29, Pages: 1349-1365, ISSN: 0929-189X
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- Citations: 2
Wang Y, Liu Y, Zheng J-H, et al., 2022, Develop a new strain rate sensitive solid-state pressure bonding model, Materials & Design, Vol: 215, Pages: 1-15, ISSN: 0264-1275
Solid-state bonding is widely involved in metal forming and joining applications. The quality of the bonded interface is the key to the final integrity of the joint or formed structure; thus, its controllability and predictivity have been the focus over decades. The interface bond quality is jointly determined by the interface oxide behaviour and microstructure evolution. In this study, a new four-stage model, considering the cohesion of different contacting pairs (oxide-oxide, oxide-metal and metal–metal) and the reduced adverse effect of remaining oxides, is proposed to describe the bonding process under hot deforming conditions. This proposed model was validated through a range of hot compression bonding tests, using Gleeble under different strains (10%, 30% and 50%), strain rates (0.001 s−1, 0.01 s−1 and 0.1 s−1) at 1150 °C with references. Scanning electron microscope (SEM) and Electron Backscatter Diffraction (EBSD) were used to characterize the oxide behaviour and microstructure evolution. Tensile tests at room temperature were conducted on bonded samples and references to reveal the interface bond ratio. 100% bonding strength, equivalent to the base metal's strength and ductility, was achieved at the large strain of 50% for all three strain rates.
Hu Y, Xi J, Jiang J, et al., 2022, Predicting virtual creep crack growth in a simulated titanium aluminide alloy microstructure containing voids, precipitates, and grain/grain boundary distortions, ENGINEERING FRACTURE MECHANICS, Vol: 262, ISSN: 0013-7944
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- Citations: 1
Wang C, Cai W, Sun C, et al., 2022, Strain rate effects on mechanical behavior and microstructure evolution with the sequential strains of TWIP steel, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, Vol: 835, ISSN: 0921-5093
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- Citations: 9
Liu Y, Wang Y, Xu X, et al., 2021, The study of hot deformation on laser cladding remanufactured 316L stainless steel, Materials and Design, Vol: 212, Pages: 1-13, ISSN: 0264-1275
Laser cladding deposition (LCD) is widely used to remanufacture/repair workpieces because of its high design freedom to rebuild areas of damage. However, the process often introduces a columnar grain structure in the cladding layer, resulting in a large variation of microstructure and hardness across the cladding layer, welding interface, and base metal. Under fatigue and tensile loading, fractures can initiate in the lower hardness cladding layer. This study explores the feasibility of a new hybrid remanufacturing method integrating the LCD with a subsequent hot deformation process to refine grain structures, reduce hardness variations, and enhance mechanical properties. The effects of deformation temperatures and imposed plastic strains were studied by examining the microstructural and stress–strain behaviour of laser cladded 316L stainless steel. After LCD, compressive deformation was imposed at temperatures of 900 and 1100 °C, with engineering strain levels of 0.1 and 0.5. A high-quality metallurgical joint was achieved, with the optimal ultimate tensile strength and yield strength under process conditions of an engineering strain level of 0.5 imposed at 900 °C (35% improvement compared to the directly laser cladding remanufacturing process). Dynamic recrystallization process was observed by the electron back scatter diffraction technique to reveal the underlying mechanism.
Xi J, Hu Y, Xing H, et al., 2021, The Low-Cycle Fatigue Behavior, Failure Mechanism and Prediction of SLM Ti-6Al-4V Alloy with Different Heat Treatment Methods, MATERIALS, Vol: 14
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- Citations: 2
Luan Q, Wang J, Huang Y, et al., 2021, How would the deformation bands affect recrystallization in pure aluminium?, Materials and Design, Vol: 209, ISSN: 0264-1275
Deformation bands (DBs), formed after plastic deformation, are known to have an impact on the recrystallization (RX) process. The exact mechanisms of how DBs influence grain nucleation and grain growth remain unclear. In this paper, deformed single and multicrystal pure aluminium samples are annealed to explore the likely effects of DBs on the grain nucleation and the subsequent grain growth. Regarding the prediction of the recrystallized (RXed) texture, it is noticeable that the orientations of nucleated grains nearby DB are originated from the orientation in DB. Regarding the nucleated positions, it is demonstrated that potential nucleation sites are more likely located in DBs in comparison with the initial grain boundary. Regarding the rate of RX, the number of nucleated grains is also predicted to have a strong positive correlation with the area fraction of DBs, which would consequently affect the kinetics of the grain growth in the deformed microstructure. All the above observations imply that the RX process is strongly controlled by the ensemble characteristics of DBs rather than the initial grain boundaries.
Huang Y, Jiang J, 2021, Microstructure and Texture Evolution during Severe Plastic Deformation at Cryogenic Temperatures in an Al-0.1Mg Alloy, METALS, Vol: 11
Wang Y, Liu Y, Lan B, et al., 2021, A study of solid-state bonding-by-hot-deforming mechanism in Inconel 718, Journal of Materials Processing Technology, Vol: 295, ISSN: 0924-0136
Solid-state bonding shows irreplaceable advantages in joining similar and dissimilar materials with poor weldability compared with fusion welding methods. To widen its applications in manufacturing safety-critical structural parts, a sound bonding quality must be achieved under less strict conditions. In this work, the metallurgical bonding is formed by hot compressing two Inconel 718 parts to different strain levels at the temperature of 1150 °C, strain rate of 0.1s−1 under a low vacuum. Full tensile strength and ductility comparable to the parent materials have been achieved for the first time by 0.5 engineering strain. The severe plastic deformation at hot temperature rapidly bonds the two parts by effectively closing the interface micro-voids, breaking up the oxide film, and in the meantime, accelerating the grain boundary(GB) migration through the dynamic recrystallization(DRx). Based on these observations, a theoretical model is proposed to describe the bonding process under hot deforming condition and the achieved relative interface bond quality, in which the cohesion between oxide-oxide and oxide-metal is assumed, and impairing effect of remaining dispersed oxides is minimized with the attempt of introducing a strain-amplifying factor. The insights and model provide the basis for further understanding of the solid-state bonding-by-hot-deforming under practical conditions and explore its wider application with ideal joint integrity.
Lan B, Wang Y, Liu Y, et al., 2021, The influence of microstructural anisotropy on the hot deformation of wire arc additive manufactured (WAAM) Inconel 718, Materials Science and Engineering A: Structural Materials: Properties, Microstructure and Processing, Vol: 823, Pages: 1-14, ISSN: 0921-5093
Hybrid additive manufacturing, incorporating additive manufacturing (AM) and other thermo-mechanical processes, has been developed to improve AM mechanical properties by modifying the as-deposited microstructure and eliminating defects. Additive manufactured parts present strong anisotropic properties, as shown by the anisotropic columnar grain morphology and texture. Samples of AM Inconel 718 were tested at high temperature and under uniaxial compression over a range of conditions. The evolution of microstructural anisotropy and the viscoplastic behaviour under these hot deformation processes was studied. The microstructure and texture evolution were characterised with optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The results show that the initial anisotropic microstructure had a negligible effect on flow stress and slip system activation during the hot deformation. The shape of original grains did, however, play a predominant role in determining the final microstructure. When the compression direction was perpendicular to the longitudinal of columnar grains, a more uniform microstructure was obtained under high-flow-stress conditions. This preferred compression direction provides guidance for hot deformation in hybrid additive manufacturing practice. Furthermore, for the nickel alloy studied, controlling the deformation direction to achieve a fine grain structure at a lower temperature (950 °C, lower than δ-solvus) brings practical benefits in the form of possible further δ grain refinement and less demanding thermal conditions during subsequent deformation processes.
Guo X, Sun C, Wang C, et al., 2021, Study of dislocation-twin boundary interaction mechanisms in plastic deformation of TWIP steel by discrete dislocation dynamics and dislocation density-based modeling, INTERNATIONAL JOURNAL OF PLASTICITY, Vol: 145, ISSN: 0749-6419
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- Citations: 21
Xiong Y, Luan Q, Zheng K, et al., 2021, Understanding the Strain Path Effect on the Deformed Microstructure of Single Crystal Pure Aluminum, METALS, Vol: 11
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Jing Y, Ren XY, Shang Y, et al., 2021, Develop a novel high-strength vacuum brazing technique for γ-TiAl intermetallic, International Journal of Lightweight Materials and Manufacture, Vol: 4, Pages: 237-245
Limited strength and ductile joints for bonding γ-TiAl intermetallics are one of the main concerns on γ-TiAl applications in the aerospace industry. In this study, a new ductile brazing filler with TiZrCuNi system was developed by an established model for calculating the electrons distribution of the unit cell for the filler. Three kinds of fillers with fixed amount of Cu and Ni as 25 wt.%, but different Zr level (25, 18, 10 wt.%) were designed. It was found that the filler diffusion was affected by the filler composition, which was insufficient with high Zr content up to 37.5 wt.%. And the defects such as the voids and the cracks were observed with medium Zr level as 25 wt.% and brazing temperature as 1000 °C. The sound joints by Zr as 18 wt.% and 10 wt.% filler at 950 °C and 980 °C respectively were achieved with tensile strength as 520 MPa–570 MPa at room temperature. This tensile strength was remained as 495 MPa in average at 600 °C. The strong joints were attributed to the fine, randomly oriented Ti3Al grains and evenly distributed elements at the interfaces.
Guo L, Yuan J, Pei J, et al., 2021, Study of the microstructure, bonding evolution and mechanical properties of continuously extruded magnesium AZ31 sheet, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, Vol: 819, ISSN: 0921-5093
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Zheng J-H, Pruncu C, Zhang K, et al., 2021, Quantifying geometrically necessary dislocation density during hot deformation in AA6082 Al alloy, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, Vol: 814, ISSN: 0921-5093
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- Citations: 12
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