TY - GEN A1 - Bolz, Sebastian A1 - Oehring, Michael A1 - Lindemann, Janny A1 - Pyczak, Florian A1 - Paul, Jonathan A1 - Stark, Andreas A1 - Lippmann, Thomas A1 - Roth-Fagaraseanu, Dan A1 - Schreyer, Andreas A1 - Weiß, Sabine A1 - Schrüfer, Susanne T1 - Microstructure and mechanical properties of a forged beta-solidifying gamma TiAl alloy in different heat treatment conditions T2 - Intermetallics Y1 - 2015 VL - 2015 IS - 58 SP - 71 EP - 83 ER - TY - GEN A1 - Naveed, Muhammad A1 - Stechow, Richard A1 - Bolz, Sebastian A1 - Hobusch, Katharina A1 - Weiß, Sabine T1 - Solid Particle Erosion of Heat Treated TNB-V4 at Ambient and Elevated Temperatures T2 - International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering Y1 - 2016 VL - 10 IS - 5 SP - 571 EP - 576 ER - TY - GEN A1 - Bambach, Markus A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Weiß, Sabine T1 - Devising Strain Hardening Models Using Kocks-Mecking Plots - A Comparison of Model Development for Titanium Aluminides and Case Hardening Steel T2 - Metals KW - titanium aluminides alloy KW - single phase steel KW - hot forming Y1 - 2016 U6 - https://doi.org/10.3390/met6090204 SN - 2075-4701 VL - 6 IS - 9 SP - 204 ER - TY - GEN A1 - Obrosov, Aleksei A1 - Gulyaev, Roman A1 - Ratzke, Markus A1 - Volinsky, Alex A. A1 - Bolz, Sebastian A1 - Naveed, Muhammad A1 - Weiß, Sabine T1 - XPS and AFM Investigations of Ti-Al-N Coatings Fabricated Using DC Magnetron Sputtering at Various Nitrogen Flow Rates and Deposition Temperatures T2 - Metals N2 - Ti-Al-N coatings were deposited by direct current magnetron sputtering (DCMS) onto IN 718 at different nitrogen flow rates and deposition temperatures. The coatings’ properties were characterized using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) as well as nanoindentation. It was found that higher deposition temperature leads to higher surface roughness and nitrogen flux influences the shape of grains. According to XPS, the bonding structure of all coatings exhibited the (Ti,Al)N phase. Mechanical properties depend on the Al content within the films. The coating with the best mechanical properties (deposited at 500 °C and 20 standard cubic centimeters per minute (sccm)) was further deposited onto tungsten carbide (WC) cutting tools for cylindrical turning experiments. A quasi-constant flank wear was observed until a machining volume of 23,500 mm³. KW - Ti-Al-N coatings KW - DC magnetron sputtering KW - XPS KW - AFM KW - nitrogen flow rate KW - surface morphology Y1 - 2017 UR - http://www.mdpi.com/2075-4701/7/2/52/htm U6 - https://doi.org/10.3390/met7020052 SN - 2075-4701 VL - 7 IS - 2 SP - 52 ER - TY - CHAP A1 - Bambach, Markus A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Weiß, Sabine T1 - Development of a dynamic recrystallization model for a β-solidifying titanium aluminide alloy using Kocks-Mecking plots T2 - ESAFORM 2016, proceedings of the 19th International ESAFORM Conference on Material Forming, Nantes, France, 27-29 April 2016 Y1 - 2016 SN - 978-0-7354-1427-3 U6 - https://doi.org/10.1063/1.4963545 SP - 160002-1 EP - 160002-7 PB - AIP Publishing CY - Melville, New York ER - TY - GEN A1 - Obrosov, Aleksei A1 - Sutygina, Alina A1 - Manakhov, Anton A1 - Bolz, Sebastian A1 - Weiß, Sabine A1 - Kashkarov, Egor B. T1 - Oxidation Behavior of Zr–1Nb Corroded in Air at 400 °C after Plasma Immersion Titanium Implantation T2 - Metals N2 - In this paper, the influence of plasma immersion titanium implantation into the zirconium alloy Zr-1Nb on the oxidation behavior at 400 °C for 5, 24, 72, and 240 h in air under normal atmospheric pressure (101.3 kPa) was shown. The influence of implantation on the protective properties of the modified layer was shown. The valence of the oxides before and after implantation was analyzed by means of X-ray photoelectron spectroscopy (XPS). Grazing incidence X-ray diffraction (GIXRD) was carried out to examine the phase composition after titanium ion implantation and oxidation. Differential scanning calorimetry (DSC) revealed that titanium implantation exhibited effects of stabilizing the β phase. The formation of the t-ZrO2 and m-ZrO2 was observed during the oxidation of the as-received and modified Zr-1Nb. The measurement of weight gain showed an improvement in oxidation resistance of Ti implanted Zr-1Nb at the oxidation up to 24 h when compared with that of the as-received Zr-1Nb. However, at longer oxidation cycle the oxidation rate of Ti-implanted zirconium alloy is the same with the as-received alloy, which attributed to the layer thickness. Nevertheless, the corrosion of the Ti-implanted alloy is more uniform, while a local corrosion and cracks was detected on the surface of the as-received alloy. KW - zirconium alloy KW - titanium KW - ion implantation KW - PIII KW - oxidation KW - DSC KW - XPS KW - surface morphology KW - X-ray diffraction Y1 - 2018 UR - http://www.mdpi.com/2075-4701/8/1/27/htm U6 - https://doi.org/10.3390/met8010027 SN - 2075-4701 VL - 8 IS - 1 ER - TY - GEN A1 - Eisentraut, Mark A1 - Stendal, Johan Andreas A1 - Bolz, Sebastian T1 - Accelerating the isothermal forging process of titanium aluminides by microstructure adaptive speed control, MSE, Darmstadt, 2018 N2 - Titanium aluminides (TiAl) are attractive materials due to their low weight, high strength, high temperature- and corrosion resistance. Currently, TiAl turbine blades produced by isothermal forging are being used in commercial aircraft jet engines. However, low ram speeds, costly dies and a required protective atmosphere makes the process relatively expensive, restricting implementation into other areas. Reducing the processing time can cut costs and in turn lead to a much wider range of applications for TiAl forgings. This project focuses on the TiAl alloy TNM-B1. During preliminary testing, the material displayed a pronounced peak in flow stress followed by a strong softening response. If this behavior can be utilized by accelerating the ram during softening, the processing time can be significantly reduced. The impact on microstructure and limits of such an acceleration are important to consider. Compression tests at constant and variable speeds are to be performed to map the flow behavior, microstructure development and damage criteria. Based on the results, a material model will be developed and used in simulations. The aim is to establish a process design, which can adapt and optimize the forging speed to a given microstructure within the limits of the material. TNM-B1 is a complex multiphase alloy, with highly varied deformation and recrystallization behaviors across the different phases. This implies the importance of a suitable heat treatment strategy to achieve high deformability during forging, as well as the desired final microstructure. Heat treatment procedures will be investigated with the aim of generating highly deformable and damage resistant microstructures prior to forging, and application specific microstructures after forging. KW - TiAl KW - Titanium aluminides Y1 - 2018 UR - https://www.mse-congress.de/program/poster-session ER - TY - GEN A1 - Eisentraut, Mark A1 - Bolz, Sebastian A1 - Sizova, Irina A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Development of a heat treatment strategy for the γ-TiAl based alloy TNM-B1 to increase the hot workability T2 - SN Applied Sciences Y1 - 2019 U6 - https://doi.org/10.1007/s42452-019-1563-4 SN - 2523-3963 SN - 2523-3971 VL - 1 IS - 11 ER - TY - GEN A1 - Stendal, Johan Andreas A1 - Eisentraut, Mark A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Effect of heat treatment on the workability of hot isostatically pressed TNM-B1 T2 - AIP Conference Proceedings Y1 - 2019 SN - 978-0-7354-1847-9 U6 - https://doi.org/10.1063/1.5112544 VL - 2113 IS - 1 ER - TY - GEN A1 - Eisentraut, Mark A1 - Stendal, Johan Andreas A1 - Bolz, Sebastian A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Applying a softening adapted acceleration to the hot deformation of TNM-B1 T2 - MRS Fall Meeting 2020 N2 - Hot isostatically forged TiAl turbine blades made of TNM-B1 are commercially used in aircraft engines, as they offer significantly lower weight than the traditional nickel-based blades while exhibiting similar strength. Like other TiAl alloys, TNM-B1 displays high peak stress followed by a strong softening behavior (i.e. stress reduction) during hot deformation. This softening can be used to accelerate the deformation process by reducing the processing time and in turn the costs for TNM-B1 parts. In order to avoid increased damage during the accelerated process, a pre-heat treatment (HT) for the hot isostatically pressed material (HIP) is required. To simulate the accelerated forming process, hot compression tests were performed with a DIL805A/D/T dilatometer from TA Instruments (New Castle, Delaware, USA) with different strain rates (0.0013, 0.005, 0.01 and 0.05) and temperatures (T=1150, 1175 and 1200°C). Deformation of the heat-treated state revealed lower flow stress (in both, peak stresses and steady state stresses) and fewer voids compared to the HIP state (Fig. 1.a). The compression test data were used to develop material and temperature specific strain rate profiles based on a material model. Subsequently, hot compression tests were performed with different strain rate profiles (starting strain rates 0.0013 and 0.0052) for the HIP and the HT state. The results were evaluated with regard to their microstructure, deformation, and damage behavior. A reduction of the processing time for all tested strain rates profiles by factors 2-3 could be achieved compared to constant strain rates. Furthermore, the results indicated that the deformation with strain rate profiles (compared to constant strain rates) did not significantly change the resulting microstructure or damage tolerance of the HT state. Y1 - 2020 UR - https://www.mrs.org/meetings-events/fall-meetings-exhibits/2020-mrs-spring-and-fall-meeting/call-for-papers/symposium-sessions-detail?code=F.SF07 ER - TY - GEN A1 - Stendal, Johan Andreas A1 - Eisentraut, Mark A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Weiß, Sabine A1 - Bambach, Markus T1 - Accelerated hot deformation and heat treatment of the TiAl alloy TNM-B1 for enhanced hot workability and controlled damage T2 - Journal of Materials Processing Technology Y1 - 2021 U6 - https://doi.org/10.1016/j.jmatprotec.2020.116999 SN - 0924-0136 VL - Vol. 291 ER - TY - GEN A1 - Emdadi, Aliakbar A1 - Bolz, Sebastian A1 - Buhl, Johannes A1 - Weiß, Sabine A1 - Bambach, Markus T1 - Laser Powder Bed Fusion Additive Manufacturing of Fe3Al-1.5Ta Iron Aluminide with Strengthening Laves Phase T2 - Metals Y1 - 2022 U6 - https://doi.org/10.3390/met12060997 SN - 2075-4701 VL - 12 IS - 6 ER - TY - GEN A1 - Yang, Yitong A1 - Eisentraut, Mark A1 - Weiß, Sabine A1 - Bolz, Sebastian T1 - Comparison of the data from two EBSD system to verify the accuracy of the technique T2 - AK Treffen Mikrostrukturcharakterisierung im REM”, Ruhr-Uni Bochum, 30. November – 1. Dezember 2023 Y1 - 2023 UR - https://www.researchgate.net/publication/377636122_Comparison_of_the_data_from_two_EBSD_system_to_verify_the_accuracy_of_the_technique_AK-Treffen_Mikrostrukturcharakterisierung_im_REM_Ruhr-Uni_Bochum CY - Bochum ER - TY - GEN A1 - Emdadi, Aliakbar A1 - Yang, Yitong A1 - Bolz, Sebastian A1 - Stryzhyboroda, Oleg A1 - Tovar, Michael A1 - Gein, Sergej A1 - Hecht, Ulrike A1 - Weiß, Sabine T1 - Mechanisms of necklace recrystallization in a BCC Fe-Al-Ta alloy with strengthening Laves phase precipitates T2 - Scripta Materialia N2 - A necklace structure composed of fine grains formed by dynamic recrystallization was uncommonly observed at the pre-existing grain boundaries during the hot compression of a BCC Fe-25Al-1.5Ta alloy containing C14 - (Fe, Al)2Ta Laves phase precipitates. Two possible mechanisms for necklace formation were proposed; particle-stimulated nucleation and grain boundary bulging, depending on whether the original grain boundaries are occupied by C14 particles, or they are free of them. Recrystallization was initiated preferentially around the clusters of large particles at the boundaries containing particles. In contrast, the bulging of the original grain boundaries by strain-induced boundary migration was observed as a preliminary stage for necklace formation at the particle-free boundaries. The necklace structure expanded into the deformed volume in such a way that low-angle subgrain boundaries decorating the necklace layers transformed into grains with increasing deformation strain. Y1 - 2023 UR - https://www.sciencedirect.com/science/article/pii/S1359646223004281 U6 - https://doi.org/10.1016/j.scriptamat.2023.115705 SN - 1359-6462 SN - 1872-8456 VL - 237 ER - TY - GEN A1 - Emdadi, Aliakbar A1 - Bolz, Sebastian A1 - Jensch, Felix A1 - Tovar, Michael A1 - Weiß, Sabine T1 - On the hot deformation of a Fe-Al-Ta iron aluminide prepared via laser powder bed fusion T2 - Crystals N2 - In the present work, a combined process of laser powder bed fusion (LPBF) and hot working in terms of microstructure refinement was investigated for Fe-25Al-1.5Ta alloy samples. Uniaxial compression tests were carried out parallel and perpendicular to the building direction (BD) at 1000 °C, where BCC A2-phase was stable, at a strain rate of 0.0013 s−1. The true stress–true strain curves indicated a broad flow stress peak followed by a slight decrease, which is typical for dynamic recrystallization (DRX) of conventional BCC metals such as ferritic iron. A negligible dependence in the flow stress behavior on the compression direction was observed. DRX initiated at a stress of 18.7 MPa for the sample compressed parallel to the BD, corresponding to a true strain of 0.011, and at 18.1 MPa for the samples compressed normal to the BD, which corresponded to a true strain of 0.010. The microstructural investigations by electron backscatter diffraction (EBSD) showed that the relatively coarse and elongated grains of the as-LPBF builds were significantly refined after hot working. The microstructure of the compressed samples mainly consisted deformed grains. These were fragmented by sub-grains bounded by low-angle boundaries independent of the compression axis, indicating the occurrence of dynamic recovery (DRV) during hot working. In addition, a few equiaxed, small grains were observed in the pre-existing grain boundaries, which formed due to DRX. Most pores in the as-LPBF builds were closed after hot compression, particularly in the central region of the deformed specimens where the compressive stress state is dominant. In summary, hot compression reveals a practical thermomechanical post-processing treatment for Fe-Al-Ta iron aluminides built by LPBF. The hot working refines the epitaxially elongated microstructure of the as-LPBF builds by DRV/DRX and reduces the porosity. Y1 - 2023 U6 - https://doi.org/10.3390/cryst13040627 SN - 2073-4352 VL - 13 IS - 4 SP - 1 EP - 12 PB - MDPI CY - Basel ER -