VEGA
Title of the project: High-strength high-entropy alloys resistant to hydrogen embrittlement (VEGA 2/0018/22)
Duration of the project: 2022 – 2025
Principal investigator: Ing. J. Lapin, DrSc. (2022-2023), Ing. M. Štamborská, PhD. (2023-2025)
The project is focused on the basic research of the effect of hydrogen on mechanical properties and deformation behaviour of high-strength high entropy alloys (HEAs) based on FCC structure. The proposed research includes material design, melting, casting, forming, heat treatment, numerical modeling, microstructure characterization, and evaluation of mechanical properties over a wide temperature range. Attention is paid to the influence of hydrogenation on the microstructure, deformation behavior and fracture of the investigated alloys. The aim of the project is a clarification of the relationships between mechanical properties, microstructure and hydrogen content. Numerical modeling combined with experimental verification of the numerical calculations, carried out by finite element method, is used to optimize the forming processes.
Title of the project: New methods for assessing road surface roughness based on motor vehicle vibration (VEGA 2/0169/22)
Duration of the project: 2022 – 2024
Principal investigator: Ing. Peter MÚČKA, CSc.
The project is focused on the design of a new indicator of road roughness, which takes into account the translational and rotational vibrations of vehicles and crew and the normal wheel forces. The new unevenness indicator will take into account both the longitudinal and transverse unevenness of the road profile and the induced vibration of the vehicle. The road roughness classification based on the new indicator will be proposed with regard to the vehicle and crew vibration thresholds. The aim is to contribute to the increase of ride safety, ride comfort and to the road network manager’s decision-making about the operational capability of communication.
Title of the project: Complex concentrated alloys for high temperature structural applications (VEGA 2/0074/19)
Duration of the project: 2019 – 2021
Principal investigator: Ing. Juraj LAPIN, DrSc.
The project was focused on the basic research of complex concentrated alloys (CCAs) for high temperature structural applications that were strengthened by intermetallic precipitates or continuous intermetallic phases. Project dealt with formation and stability of intermetallic phases in a disordered solid solution based on CoCrFeNi with an equimolar concentration of principal elements which were alloyed with other additions (Al, Ti, Si, C, B). The fundamental aspects of microstructure formation and microstructure stability during high temperature loading were clarified. The effect of alloying elements on phase transformations, phase transformation temperatures, precipitation and growth of intermetallic phases in new CCAs was explained. The relationships between microstructure and mechanical properties were elucidated. Numerical calculations of the deformation behaviour by finite element method was supported experimentally.
Title of the project: Influence of transverse and longitudinal road unevenness on a whole-body vibration of driver/passenger in a motor car(VEGA 2/0148/19)
Duration of the project: 2019 – 2021
Principal investigator: Ing. Peter MÚČKA, CSc.
The project was aimed at experimentally determining the dependence between the parameters of road transverse and longitudinal unevenness and the driver/passenger ride comfort in a motor vehicle. The relationship between the transverse and longitudinal unevenness parameters and the whole-body vibrations of the vehicle crew was determined. An unevenness indicator using transverse and longitudinal unevenness parameters was proposed, which took into account the induced whole-body vibrations of the crew.
APVV
Title of the project: Hydrogen embrittlement resistance of precipitation hardened complex concentrated alloys (APVV-20-0505)
Duration of the project: 2021 – 2024
Principal investigator: Ing. J. Lapin, DrSc. (2021-2023), Ing. K. Kamyshnykova, PhD. (2023-2024)
Project is focused on the basic research of the unexplored effect of hydrogen on microstructure, deformation behaviour and fracture of precipitation hardened complex concentrated alloys (CCAs). The project deals with metallurgical preparation, optimisation and characterisation of CCAs with FCC+BCC(B2) and FCC+L12 type of structures that are being developed for high-temperature structural applications. The effect of precipitates on hydrogen absorption is assessed by comparison of the hydrogen amount in precipitation-hardened CCAs to that in reference high entropy alloys. The effect of the hydrogen on mechanisms controlling plastic deformation and fracture is studied in single-crystal specimens with defined crystallographic orientation. The influence of grain boundaries on hydrogen embrittlement is assessed using specimens with columnar and equiaxed grain structure. The analytical and finite element methods are used in modelling of tensile, quasi-static three-point bending and impact fracture toughness behaviour. The validity and accuracy of numerical calculations are verified experimentally.
Title of the project: New high temperature composite materials for turbochargers (APVV-15-0660)
Duration of the project: 2016 – 2020
Principal investigator: Ing. J. Lapin, DrSc.
The project was focused on basic research in the field of lightweight high-temperature materials designated for structural applications up to 900 °C in the automotive, aviation and energy industries. A new type of in-situ composites with lamellar intermetallic γ(TiAl) + α2(Ti3Al) matrix reinforced with carbide particles was prepared by addition of TiC powder to the melts prepared by TiAl-based alloys and their casting. The lower price and higher high-temperature properties of the new in-situ composites compared to the already used or developed TiAl-based intermetallic alloys were achieved using the original technology of their production, which ensures the uniform distribution of primary Ti2AlC particles in the matrix during crystallization and the formation of secondary fine carbide precipitates by suitable heat treatment in the solid state. By changing the volume fraction and size of the primary carbide particles, choosing the chemical and phase composition of the matrix with different type and size of fine secondary precipitates, it is possible to design the mechanical properties of these new composites for various specific structural applications. The developed technology for the preparation of in situ composites, consisting of melting and casting, makes it possible to prepare castings in which the volume fraction of carbide particles can be regulated from 2 to 23% and the microstructure of the matrix can be changed from single-phase TiAl to lamellar TiAl+Ti3Al. Numerical simulation models were designed to predict the deformation behavior of the investigated materials. The validity and accuracy of the numerical calculations was verified on the basis of experimental data from mechanical tests and simulation deformation experiments.