Valéria Mertinger

Continuous dynamic recrystallization (CDRX) is commonly regarded as a one-way process in which grain size decreases continuously through grain fragmentation with increasing plastic deformation. In this study, the role of texture evolution in CDRX during large shear deformation is investigated using a combination of experiments, analytical modeling, and polycrystal plasticity simulations. The results demonstrate that CDRX can be modeled by lattice curvature induced concurrent operation of grain fragmentation and grain coalescence, both strongly controlled by texture evolution. Divergence rotation fields promote grain fragmentation by increasing disorientation between adjacent subgrains, whereas convergence rotation fields reduce orientation differences between neighboring grains, thereby facilitating grain coalescence, particularly near ideal orientations. This behavior is confirmed experimentally in a severely deformed copper sample and successfully reproduced using a four-level fractal-type grain refinement model based on lattice curvature induced CDRX coupled with a polycrystal plasticity framework. Particularly, the simulations show that grain coalescence is not a rare event but an intrinsic component of CDRX, actively contributing to grain size evolution. These findings provide a new framework for understanding grain refinement under severe plastic deformation and establish texture evolution as a key parameter for controlling microstructure design.

Many processing companies use some grades of steel for cold forming. Due to ageing, the formability of unalloyed mild steel sheets deteriorates over time; their formability is not uniform, and surface defects appear, which in many practical applications leads to scrap. This can be particularly important for processing companies when selecting machine settings, as there may be differences in the properties of materials from different manufacturers and the properties of materials of different ages from the same manufacturer. We investigated the ageing behaviour of DC01 steel grade by testing many samples from the third day after production up to one year. Various methods were used to detect ageing, such as tensile tests at different test speeds and supplemented with a digital image correlation (DIC) system, thermo-electric power measurement, deep drawing cup tests, and Nakajima tests. We showed that a reinterpretation of the definition of ageing is necessary. Standard tensile testing can no longer detect the ageing tendency of steels manufactured using the latest technology. However, when supplemented with DIC, these tests show ageing with high sensitivity. Among the used methods the applicability of this technique in industrial material testinglaboratories is the most recommended.

Volume 1 of the FCC Feasibility Report presents an overview of the physics case, experimental programme, and detector concepts for the Future Circular Collider (FCC). This volume outlines how FCC would address some of the most profound open questions in particle physics, from precision studies of the Higgs and EW bosons and of the top quark, to the exploration of physics beyond the Standard Model. The report reviews the experimental opportunities offered by the staged implementation of FCC, beginning with an electron-positron collider (FCC-ee), operating at several centre-of-mass energies, followed by a hadron collider (FCC-hh). Benchmark examples are given of the expected physics performance, in terms of precision and sensitivity to new phenomena, of each collider stage. Detector requirements and conceptual designs for FCC-ee experiments are discussed, as are the specific demands that the physics programme imposes on the accelerator in the domains of the calibration of the collision energy, and the interface region between the accelerator and the detector. The report also highlights advances in detector, software and computing technologies, as well as the theoretical tools/reconstruction techniques that will enable the precision measurements and discovery potential of the FCC experimental programme. The content and structure of this report are guided by the scope and priorities defined in the mandate of the FCC Feasibility Study. It is therefore not intended to serve as an exhaustive review of the full physics potential of FCC. Several topics, already covered in earlier reports such as the FCC CDR, are not reiterated here or are addressed only briefly, in alignment with the study’s focus. This volume reflects the outcome of a global collaborative effort involving hundreds of scientists and institutions, aided by a dedicated community-building coordination, and provides a targeted assessment of the scientific opportunities and experimental foundations of the FCC programme.