13th International Conference on the Technology of Plasticity (ICTP 2021): Microstructure Development by Forming II
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Wednesday 10:20 AM
July 28, 2021
Room: Virtual: Room E
Location: Virtual
Session Chair: Wojciech Misiolek, Lehigh University
Metal Foils for Bipolar Plates – Correlation of Initial Grain Size and Forming Behavior of 316L: Alexander Bauer1; Thomas Mehner1; Birgit Awiszus1; Thomas Lampke1; 1University of Technology Chemnitz
As the forming of metallic bipolar plates is mostly still state of research, the underlying forming mechanisms are not fully understood. This study deals with the topic of different grain sizes in the initial metal sheets and their influence on the forming results. Therefore, a work hardened 316L-foil (0.1 mm) was processed with different heat-treatment strategies resulting in three different grain sizes with average grain diameters of 47.4 µm, 19.3 µm and 7.9 µm. Afterwards, all heat-treated blanks were cut and deep drawn between two rigid dies to form a bipolar plate flow field. Besides force and geometrical factors like thinning and springback, the microstructure was analyzed by XRD and EBSD. Using these characterization methods, the mechanisms of twinning and preferred deformation of specific grain orientations during the forming process can be identified. Therefore, the impact of size effects on the forming behavior of metallic bipolar plates was shown.
Cancelled
Analysis of the Microstructural Forming Behavior of 316L Metal Foils with Different Initial Grain Sizes for the Production of Metallic Bipolar Plates: Alexander Bauer1; Thomas Mehner1; Birgit Awiszus1; Thomas Lampke1; 1University of Technology Chemnitz
As the forming of metallic bipolar plates is mostly still state of research, the underlying forming mechanisms are not fully understood. This study deals with the topic of different grain sizes in the initial metal sheets and their influence on the forming results. Therefore, a work hardened 316L-foil (0.1 mm) was processed with different heat-treatment strategies resulting in three different grain sizes with average grain diameters of 47.4 µm, 19.3 µm and 7.9 µm. Afterwards, all heat-treated blanks were cut and deep drawn between two rigid dies to form a bipolar plate flow field. Besides force and geometrical factors like thinning and springback, the microstructure was analyzed by XRD and EBSD. Using these characterization methods, the mechanisms of twinning and preferred deformation of specific grain orientations during the forming process can be identified. Therefore, the impact of size effects on the forming behavior of metallic bipolar plates was shown.
T8 Heat Treatment Effect on Wear Behavior and Microstructure of Cryo and RT Ecaped Al 6063: A. Sreenivasulu1; Swami Naidu Gurugubelli1; 1J N T U K University College of Engineering
The effect of T8 heat treatment on wear behaviour of AA6063 were studied and precipitation kinetics was evaluated by SEM and XRD studies. AA6063 square rods of 9.5 mm X 9.5 mm X 100mm were solution treated at 5200C for 2hrs and quenched in water. One set of samples were processed by ECAP at room temperature and the other set were processed by Cryogenic ECAP after soaking in liquid nitrogen for 20 minutes. A die of 1080 channel intersection angle and 360 outer curvature angle was used and each sample was given four passes in route A and aged at 1800C. Hardness measurements were obtained at regular intervals and wear tests were conducted on pin-on-disc wear testing machine. SEM images were obtained and the wear behaviour of the alloy was correlated with the microstructures. Much improvement in wear resistance was observed in the alloy processed by cryo-ECAP.
Development and Implementation of Static Recrystallization Model of 6XXX Aluminum Alloy Using Industrial Experiments: Artem Alimov1; Ivan Kniazkin2; Nikolay Biba3; 1Brandenburg University of Technology Cottbus-Senftenberg; 2Bauman Moscow State Technical University; 3Micas Simulations Limited
The paper focuses on the development of a static recrystallization model of 6XXX aluminum alloy based on industrial profiles extrusion analysis. 6XXX aluminum alloys are widely used for complex shapes with smooth surfaces suitable for visible architectural applications. Mechanical properties and surface defects, for example, streaking lines, are dependent on the microstructure. Static recrystallization occurs in alloys such as 6XXX due to high stacking fault energy. At the moment, there is no reliable static recrystallization model of 6XXX aluminum alloys found in the literature. In the presented paper a new approach has been proposed to determine the parameters of Johnson-Mehl-Avrami-Kolmogorov equation. It is based on using of strain and temperature history during extrusion of industrial profiles and examining the microstructure in their cross-sections and implementing of the inverse analysis approach. The developed model has been verified and used for simulation of the microstructure evolution in industrial extrusion cases and has shown sufficient accuracy.
Non-isothermal modeling of static recrystallization in hydroformed steel tube using a coupled Cellular Automata and Finite Element model: Amir Asgharzadeh1; Sobhan Alah Nazari Tiji1; Taejoon Park1; Farhang Pourboghrat1; 1The Ohio State University
An accurate thermo-microstructural modeling setup was developed to model the kinetic of static recrystallization during annealing of hydroformed steel tube under non-isothermal condition. In this model, a coupled Cellular Automata and Finite Element thermal model was implemented to predict the kinetic of static recrystallization, which also accounts for the impact of multiaxial deformation and annealing temperature regime. First, an exact analytical solution was developed to calculate the flow behavior of steel tube during hydroforming experiment based on the data extracted from digital image correlation measurements. Second, the actual microstructure and orientation of the as-deformed material was obtained with EBSD test. Third, the calculated deformation characteristics as well as the obtained crystallographic and microstructural data were imported to the developed Finite Element-Cellular Automata model to predict the progress of static recrystallization and temperature changes during annealing. The results show that there is a reasonable agreement between the experimental data and predictions, confirming the accuracy of developed modeling setup in prediction of the progress of static recrystallization within hydroformed steel tubes.