| 1. |
- Bello bermejo, Juan manuel, et al.
(författare)
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A Methodology Using Monte-Carlo Simulation on Nanoindentation Deconvolution for Metal Classification
- 2024
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Ingår i: Proceedings of the 11th Swedish Production Symposium (SPS2024). - 2352-751X .- 2352-7528. - 9781643685113 - 9781643685106 ; 52, s. 613-627
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Bokkapitel (refereegranskat)abstract
- This paper investigates a methodology for the precise statistical deconvolution of hardness properties within various metallic matrix multiphase materials. The central focus is on accurately characterizing mechanical behaviour in the context of complex materials. To meet these objectives, we implemented an approach involving nanoindentation analyses of the selected materials. This technique allowed for the creation of material profiles based on micromechanical properties. Statistical cumulative density function (CDF) deconvolution was employed to disentangle the complex distributions of multiphase material hardness using cross-validation. Throughout the course of this study, several multicomponent CDF combinations were tested, including Weibull, Exponential, and Gaussian distributions. This approach challenges the conventional practice of assuming multiple Gaussian distributions of hardness, revealing the limitations of this approach. In addition, Monte-Carlo simulations were harnessed to generate probability density functions (PDFs) that capture the intricate footprint variations in hardness profiles. By implementing our methodology, we strive to offer a comprehensive and refined approach to materials analysis. This potential for differentiation has the significant implication of investigating the impact of impurities and trace elements on the mechanical properties and thus, machinability of metal materials. The ultimate aim is to enhance their recyclability, thereby advancing the principles of the circular economy and contributing to the sustainable development goals. Our study thus underscores the profound impact of material analysis on environmental sustainability and the efficient use of resources, while offering a fresh perspective on the role of statistics in materials science.
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| 2. |
- Choudary Ratnala, Dilipkumar, Doktorand, et al.
(författare)
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Effect of Laser Power on the Deposition of Alloy 718 Powder on Alumina Substrate Using Laser Directed Energy Deposition : A Single-Track Study
- 2024
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Ingår i: Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning. - : IOS Press. - 9781643685106 - 9781643685113 ; , s. 111-121
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Bokkapitel (refereegranskat)abstract
- Welding or brazing of metals to ceramics often leads to failures under aggressive conditions due to abrupt changes in physical, chemical, and thermal properties at the metal-ceramic interface. Metal-ceramic Functional Graded Materials (FGMs) replace the strict interface with a gradual transition of composition and properties, which protects the material from failures. The powder-blown Laser-Directed Energy Deposition (DED-LB) is one of the widely known Additive Manufacturing (AM) processes that offer unique features like developing FGMs and multi-material structures. Various studies have been conducted to process metalceramic FGMs using the DED-LB process but significant differences in thermal properties, varying laser-material interactions, and the possibility of formation of complex reaction products make the processing of metal-ceramic FGMs challenging. This study aims to understand the effect of laser power on a ceramic substrate, and its interaction with a metal powder introduced in the melt pool. A single track of nickel-based superalloy Alloy 718 powder was deposited on an Alumina substrate with different laser powers. The deposition was performed with and without substrate pre-heat to understand the effect of pre-treatment on deposition. Metallographic analysis was performed to reveal the microstructure of the resolidified metal mixed ceramic region
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| 3. |
- Eriksson, Emil, 1990, et al.
(författare)
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Dynamic recrystallization during hot compression of Ni-based superalloy Haynes 282
- 2023
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Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 960, s. 170837-170837
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the microstructural behaviour of materials during thermomechanical processing is a vital step towards optimizing the mechanical properties. One important aspect during forming processes, such as forging, is dynamic recrystallization (DRX), which sets the starting microstructure for the subsequent manufacturing steps. Here we investigated the DRX behaviour of Ni-base superalloy Haynes 282 during hot compression with a strain rate of 0.05 s−1 at 1080 °C, with care taken to minimize the effects of meta-dynamic recrystallization (mDRX) and adiabatic heating. Small DRX grains could be observed already at ε = 0.1, i.e. before the peak strain εp = 0.15. The DRX process accelerated significantly above ε = 0.2, and the material was fully recrystallized at ε = 1.5. Up to ε = 0.8 DRX occurred through continuous nucleation of new grains, whereas above ε = 0.8 the number density of DRX grains decreased and the increase in recrystallized fraction was due to growth of existing grains. Contrary to common assumptions of DRX nuclei being essentially dislocation free, many of the DRX grains contained pronounced dislocation substructures, even at small strains where they are not expected to have undergone deformation.
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| 4. |
- Eriksson, Emil, 1990, et al.
(författare)
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Meta-Dynamic Recrystallization in the Ni-Based Superalloy Haynes 282
- 2023
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Ingår i: Metals. - : MDPI. - 2075-4701. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Forging on an industrial scale often involves slow, size-limited cooling rates or high temperature hold times between, or after, deformation. This enables the dynamic recrystallization (DRX) initiated during forging to further progress under static conditions, a phenomenon called meta-dynamic recrystallization (mDRX). As mDRX will influence the final grain size, and thus properties, it is critical to understand and control it during processing. Here, we study the mDRX evolution in Ni-based superalloy Haynes 282 during post-deformation hold times of up to 120 s at 1080 °C after partial DRX. We find that mDRX is the dominating mechanisms responsible for the microstructure evolution the hold time. The very rapid mDRX kinetics in the initial stages suggest that quench delays (the time between the end of the deformation and the onset of the quenching intended to arrest the microstructure evolution) must be kept well below 1 s in order to allow reliable conclusions to be drawn from post-deformation microstructure investigations. A larger prior strain (larger DRX fraction) leads to faster mDRX kinetics and a larger final grain size. Larger strains leads to earlier impingement of the growing grains, which, in combination with smaller remaining deformed regions into which the grains can grow, limits the maximum size of the mDRX grains. We also note a close correlation between static recovery and stress relaxation during the hold time, whereas no such correlation between mDRX and stress relaxation can be observed.
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| 5. |
- Hanning, Fabian, 1988, et al.
(författare)
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A Review of Strain Age Cracking in Nickel Based Superalloys
- 2016
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Ingår i: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings. - Lund : Swedish Production Academy. ; , s. 1-7
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Konferensbidrag (refereegranskat)abstract
- This paper reviews the literature with emphasis on strain age cracking, a cracking phenomenon that can occur during welding or heat treatment of precipitation hardening superalloys. The influence of chemical composition in terms of e.g. hardening elements and impurities, microstructure of base material and weld zone, precipitation-induced stress development, welding heat input, restraint and post weld heat treatment (PWHT) conditions is discussed and related to the cracking susceptibility of different nickel based superalloys. Furthermore, an overview on available testing methods is presented and scrutinized. As of now, neither a standardized nor universally applicable procedure is available where the now existing tests generally can be divided into two groups; procedures representing actual welds usually providing qualitative comparisons under specified conditions, and simulative tests like those based on the Gleeble® system which can provide fundamental insight into the ongoing mechanisms.
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| 6. |
- Hanning, Fabian, 1988, et al.
(författare)
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Advanced microstructural characterisation of cast ATI 718Plus®—effect of homogenisation heat treatments on secondary phases and repair welding behaviour
- 2020
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Ingår i: Welding in the World, Le Soudage Dans Le Monde. - : Springer Science and Business Media LLC. - 1878-6669 .- 0043-2288. ; 64:3, s. 523-533
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Tidskriftsartikel (refereegranskat)abstract
- The influence of base metal conditions on the weld cracking behaviour of castATI 718Plus® is investigated by comparing 4 h and 24 h dwell time pseudo-hip homogenisation heat treatments at 1120, 1160 and 1190 °C with the as-cast microstructure. Scanning electron microscopy (SEM), X-ray diffraction (XRD) on electrolytically extracted powder and transmission electron microscopy (TEM) were used to identify Nb-rich secondary phases in interdendritic areas as the C14 Laves phase and Nb(Ti) MC-type carbides. All homogenisation heat treatments but the 1120 °C 4-h condition dissolve the Laves phase. A repair welding operation was simulated by linear groove multi-pass manual gas tungsten arc welding (GTAW). The Laves phase containing microstructures resulted in lower total crack length for heat affected zone cracking. Constitutional liquation of Nb(Ti) MC-type carbides is observed as a liquation mechanism in Laves-free microstructure, while thick liquid film formation due to the Laves eutectic melting could reduce the formation of weld cracks in microstructures containing the Laves phase.
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| 7. |
- Hanning, Fabian, et al.
(författare)
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Effect of Short-Term Isothermal Exposure on the Ductility Signature of Waspaloy in the Temperature Range of 750–950 °C: A Comparison with Haynes® 282®
- 2023
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Ingår i: Proceedings of the 10th International Symposium on Superalloy 718 and Derivatives. - : Springer Nature. - 9783031274466 - 9783031274473 ; , s. 197-210
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Konferensbidrag (refereegranskat)abstract
- The evolution of microstructure and ductility has been investigated for Waspaloy after isothermal exposure between 5 and 1800s at 750–950 °C. Gamma prime (γ’) with 1.7 nm diameter is found in the mill-annealed condition, while precipitate-growth following a t1/3 relationship is observed for isothermal exposure. Grain boundary carbide networks are formed during isothermal exposure together with a rapid hardness increase. A drop in ductility is observed with the lowest values at 750 and 800 °C. Further ductility reduction during isothermal exposure correlates with the rapid hardness increase of Waspaloy. While grain boundary strengthening can compensate for the moderate age hardening observed for Haynes® 282®, the more rapid hardness increase due to γ' precipitation appears to be the dominating effect on ductility in Waspaloy. Carbide precipitation and growth kinetics are slower than those of Haynes® 282®, which further increases the relative effect of age hardening reactions on the ductility of Waspaloy.
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| 8. |
- Hanning, Fabian, 1988, et al.
(författare)
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Investigation of the Effect of Short Exposure in the Temperature Range of 750-950 degrees C on the Ductility of Haynes (R) 282 (R) by Advanced Microstructural Characterization
- 2019
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Ingår i: Metals. - : MDPI. - 2075-4701. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- A Gleeble-based test method has been developed to study the change in the ductility signature of Haynes (R) 282 (R) during isothermal exposure from 5 s to 1800 s. A temperature range of 750 to 950 degrees C has been used to investigate the effect of age-hardening reactions. Microstructural constituents have been analyzed and quantified using scanning and transmission electron microscopy. Carbides present in the material are identified as primary MC-type TiC carbides, Mo-rich M6C secondary carbides, and Cr-rich M23C6 secondary carbides. Gamma prime (gamma’) precipitates are present in all the material conditions with particle sizes ranging from 2.5 nm to 58 nm. Isothermal exposure causes the growth of gamma’ and development of a grain boundary carbide network. A ductility minimum is observed at 800-850 degrees C. The fracture mode is found to be dependent on the stroke rate, where a transition toward intergranular fracture is observed for stroke rates below 0.055 mm/s. Intergranular fracture is characterized by microvoids present on grain facets, while ductility did not change during ongoing age-hardening reactions for intergranularly fractured Haynes (R) 282 (R).
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| 9. |
- Hanning, Fabian, et al.
(författare)
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Measurement of the thermal cycle in the base metal heat affected zone of cast ATI ® 718Plus TM during manual multi-pass TIG welding
- 2018
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Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 25, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method to acquire thermal data in the base metal heat affected zone (HAZ) during manual multi-pass TIG welding of ATI ® 718Plus TM , representing conditions close to an actual repair welding operation. Thermocouples were mounted in different locations along side walls of linear grooves to record temperature data. The thermal cycling was found to be largely independent of location within the HAZ. The recorded temperatures were below the incipient laves melting temperature, indicating that the current test setup requires optimisation to study HAZ liquation. Based on the results of this study, a modified thermocouple mounting technique is proposed. © 2018 Elsevier B.V. All rights reserved.
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| 10. |
- Hanning, Fabian, et al.
(författare)
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The Effect of Grain Size on theSusceptibility Towards Strain Age Crackingof Wrought Haynes® 282®
- 2020
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Ingår i: SPS 2020. - Amsterdam : IOS Press. - 9781643681467 - 9781643681474 ; 13, s. 407-416
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The effect of grain size on the suceptibility towards strain age cracking (SAC) has been investigated for Haynes® 282® in the tempeature range of 750 to 950°C after isothermal exposure up to 1800s. Grain growth was induced by heattreating the material at 1150°C for 2h, resulting in a fourfold increase in grain size. Hardness was significanlty reduced after heat treatment as compared to millannealed material. Large grain size resulted in intergranular fracture over a widertemperature range than small grain size material. Ductility was lowest at 850°C, while lower values were observed to be correlated to increased grain size. The rapid formation of grain boundary carbide networks in Haynes® 282® is found to be notable to compensate for higher local stresses on grain boundaries due to incresedgrain size.
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