Academy Plenary Speaker

Erman Tekkaya (Germany): (Bio)

Damage in Metal Forming: Enhancing Product Properties

Metal forming does not only shape the product but also influences its properties. These properties determine the performance of the component in service. The damage level after forming is an important property of formed components. The presentation will provide the experimental evidence that damage induced during metal forming significantly influences the performance of the formed part. For this purpose, carefully designed experiments allowing the isolated analysis of damage will be presented. The physical mechanisms of ductile damage in metal forming, experimental characterisation methods for damage, and stress measures allowing the prediction of the damage level in formed components are discussed. Starting with the key idea that damage is not failure, it will be shown that the damage level in formed components can be controlled by the parameters of the forming process. Examples from bulk and sheet forming will be given to demonstrate that the components with reduced damage levels have better performance in service in terms of fatigue life, impact energy, and stiffness. Finally, methods for the industrial utilisation of damage control will be discussed, and the paradigm change from formability to usability in metal forming will be promoted. 

Linfa Peng (China): (Bio)

Development of Micro-forming Technologies for Metallic Bipolar Plates

Metallic bipolar plates (BPPs) are crucial components in proton exchange membrane fuel cells (PEMFCs). Fabricated from ultrathin metallic sheets, they are featured with hundreds of micro-channels, which play a pivotal role in the overall performance of PEMFCs. However, the micro-forming of such ultrathin metallic sheets with high precision and robustness remains a formidable challenge. In that regard, this lecture focuses on the development and advancement of micro-forming technologies for ultrathin metallic sheets. Through a combination of experimental investigations, theoretical analyses, and multiscale simulations, we systematically reveal the size effects on key forming behaviors of ultrathin metallic sheets, such as flow stress, forming limits, and springback. Based on these fundamental insights, a multi-stage micro-forming process has been developed. Industrial validation results demonstrate that the optimized process remarkably improves the forming quality and dimensional consistency of metallic BPPs, thereby providing critical technical support for the manufacturing of metallic BPPs in PEMFC applications.

Jian Cao (USA): (Bio)

Physics-based AI-assisted Design and Control of Manufacturing Processes

Current research efforts at my group aim to advance the capability to co-design materials and manufacturing processes using hybrid physics-based and data-driven approaches. In this talk, I will demonstrate our work in the development of differentiable simulation tools, sensing, and process control to achieve effective and efficient predictions and control of a material’s mechanical behavior in metal forming processes. Furthermore, I will show how we use machine learning to accelerate the physics-based simulations. Our solutions particularly target three notoriously challenging aspects of the process: long history-dependent properties, complex geometric features, and the high dimensionality of their design space. The approaches are applicable to other manufacturing processes as well, such as additive manufacturing.

Jun Yanagimoto (Japan): (Bio)

Design of macrostructure and forming of CFRP-metal sandwich sheet for the future technology of plasticity

CFRP is the promising material for the lightweight constructions. Forming of solidified CFRP sheet had been regarded as extremely difficult or impossible due to very poor elongation beyond the elastic limit. In the last decade, warm stamping of solidified CFRP sheet using a pair of dummy sheets had been proposed, and it had been applied to the deep drawing of elliptic cup. The research had been extended to the forming of sandwiched CFRP sheet, in which macrostructure of core is designed to have the sufficient formability and bonding strength with the face sheets. The overview of this research area will be reviewed in this lecture.

Paulo A. F. Martins (Portugal): (Bio)

From Simulation to Production: Numerical, Experimental, and Technological Innovations in Collector Coin Minting

This presentation begins with a comprehensive state-of-the-art review of published scientific research on coin minting since the early 1960s. It proceeds to examine recent technological advancements resulting from innovations in design, materials, and manufacturing processes, with particular attention to hybrid approaches that integrate additive manufacturing and joining by forming with coin minting. The presentation then details recent contributions by the presenter and collaborators, including methods for material characterization, the development of finite element computer programs to create digital twins of coin minting, and advancements in coin and die design through novel methodologies, materials, and manufacturing techniques. The presentation concludes by showcasing numerical and experimental prototypes, several of which have been successfully implemented in the production of collector coins.

Coin minting, while a specialized area within metal forming, is a net-shape cold-forging process that enables the production of complex geometries with extremely small and accurate details. It involves applying exceptionally high pressures to dies and presents exciting manufacturing challenges, such as integrating additive manufacturing and joining by forming, and combining noble metals with polymers and other materials.

Heung Nam Han (Korea): (Bio)

From Heat to Charge: Electric Current/Charge-Enhanced Plasticity and Phase Transformation for Sustainable Electrification of Materials Processing

The thermodynamic stability of materials is traditionally governed by temperature, pressure, and chemical composition, with Gibbs free energy serving as the fundamental criterion for phase stability. This study investigates whether the application of electric current, or more broadly, electric charge, can alter the free energy of materials, thereby influencing their deformation behavior and phase transformation. Ab-initio simulations and experiments reveal that charge imbalances near defects weakens atomic bonding, lowers the energy barrier for dislocation motion, and promotes electroplasticity. This suggests that plastic deformation is enhanced under electric current without significant Joule heating. To further quantify this effect, the α/β phase transition temperature of pure titanium was analyzed under current-assisted and purely thermal conditions using in-situ neutron diffraction. The observed shifts in transformation temperature confirm an athermal contribution of electric current/charge, which can be expressed as an additional Gibbs free-energy term. This concept enables the construction of a pseudo-phase diagram using microstructure and current density as state variables. Complementary studies on ultra-low-carbon steel demonstrate that recovery, recrystallization, and grain growth initially decrease with increasing current density, reinforcing the existence of an athermal effect. Finally, sub-second electric pulsing was employed to achieve rapid and repeatable microstructure resetting. This self-healing process was demonstrated in SUS301L and NiTi alloys through current-induced accelerated kinetics. Furthermore, this presentation discusses how electrification, which will increasingly be utilized in materials processing due to decarbonization, alters materials behavior.

Mark A. Iadicola (USA): (Bio)

Validation of Extending the Uniaxial Test Beyond Uniform Elongation Using Combined DIC and X-Ray Diffraction

The uniaxial tension test is one of the most common tests used to develop data for finite element modeling (FEM) of industrial processes.  A major limitation to the uniaxial test is that it is only valid up to the ultimate tensile strength (UTS) (i.e. during uniform elongation) after which a diffuse neck forms and the uniaxial stress condition is no longer ensured.  In the case of sheet metal forming operations, the applied deformation often results in large strains beyond the uniform elongation of a uniaxial test.  To train the FEM for strains beyond uniform elongation one of three approaches are typically used, each with their own shortcomings. (1) Perform additional testing (e.g. shear or biaxial) to larger strains and a priori select the point to switch from the uniaxial test data to the alternative test data.  (2)  Extrapolate the existing stress-strain data assuming a function-based model (i.e. Hollomon, Voce, etc.) which may, or may not, match the real material behavior.  (3) Use full-field strain data from more advanced measurement techniques (e.g. digital image correlation, DIC) during the uniaxial test to determine true stress and true strain inside of the necking region using force divided by current cross-sectional area. However, since the area of the neck could have a multiaxial state of stress, other corrections (e.g. Bridgman) might have to be assumed when using the full-field strain method. In this work, a unique combination of DIC and in situ X-ray diffraction (XRD) was used to measure the multiaxial stress and strain response in the neck of tensile specimens cut from ASTM A1008 steel sheet.  The results show that the stress state remains largely uniaxial until three times the conventional UTS strain limit.  Therefore, it is found that adding DIC along with proper measurement interpretation can accurately assess the stress-strain behavior to much larger strains than previously known.  This data serves as an empirical basis for possible validation of various methods of post-UTS stress-strain extrapolation. 

Andrea Ghiotti (Italy): (Bio)

Advancing forging technologies for the green transition: from high-performance alloys to sustainable process chains

In the contemporary industrial landscape, the forging sector is facing a significant paradigm shift to address the dual challenges of extreme performance requirements and the urgent need for decarbonization. This plenary lecture explores the strategic evolution of forging technologies through the lens of environmental sustainability. The presentation highlights how advanced thermo-mechanical characterization of high-performance materials –such   as titanium and nickel-based superalloys– enables the optimization of material usage and energy efficiency across the entire production cycle. Central to this transition is the development of innovative, eco-friendly lubrication systems designed to replace traditional hazardous substances, alongside the implementation of near-net-shape forging strategies aimed at minimizing material scrap and reducing the energy intensity of secondary processing. By bridging fundamental plasticity science with industrial-scale process design, the lecture outlines a comprehensive roadmap for transforming forging into a primary enabler of a circular and low-emission manufacturing economy.