Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk


Agnieszka Grabias

Lukasiewicz Institute of Microelectronics and Photonics (PL)

Ostatnie publikacje
1.  Strojny-Nędza A., Pietrzak K. Z., Jóźwik I., Bucholc B., Wyszkowska E., Kurpaska Ł., Grabias A., Malinowska A., Chmielewski M., Effect of Nitrogen Atmosphere Annealing of Alloyed Powders on the Microstructure and Properties of ODS Ferritic Steels, Materials, ISSN: 1996-1944, DOI: 10.3390/ma17081743, Vol.17, No.8, pp.1-19, 2024

Oxide Dispersion Strengthened (ODS) ferritic steels are promising materials for the nuclear power sector. This paper presents the results of a study on the sintering process using the Spark Plasma Sintering (SPS) technique, focusing on ODS ferritic steel powders with different contents (0.3 and 0.6 vol.%) of Y2O3. The novelty lies in the analysis of the effect of pre-annealing treatment on powders previously prepared by mechanical alloying on the microstructure, mechanical, and thermal properties of the sinters. Using the SPS method, it was possible to obtain well-densified sinters with a relative density above 98%. Pre-annealing the powders resulted in an increase in the relative density of the sinters and a slight increase in their thermal conductivity. The use of low electron energies during SEM analysis allowed for a fairly good visualization of the reinforcing oxides uniformly dispersed in the matrix. Analysis of the Mössbauer spectroscopy results revealed that pre-annealing induces local atomic rearrangements within the solid solution. In addition, there was an additional spectral component, indicating the formation of a Cr-based paramagnetic phase. The ODS material with a higher Y2O3 content showed increased Vickers hardness values, as well as increased Young’s modulus and nanohardness, as determined by nanoindentation tests.

Słowa kluczowe:
spark plasma sintering, ODS ferritic steel, mechanical alloying, Mössbauer spectroscopy, nanoindentation

Afiliacje autorów:
Strojny-Nędza A. - Institute of Electronic Materials Technology (PL)
Pietrzak K. Z. - IPPT PAN
Jóźwik I. - Institute of Electronic Materials Technology (PL)
Bucholc B. - IPPT PAN
Wyszkowska E. - National Centre for Nuclear Research (PL)
Kurpaska Ł. - National Centre for Nuclear Research (PL)
Grabias A. - Lukasiewicz Institute of Microelectronics and Photonics (PL)
Malinowska A. - inna afiliacja
Chmielewski M. - Institute of Electronic Materials Technology (PL)
2.  Nosewicz S., Jurczak G., Wejrzanowski T., Ibrahim S.H., Grabias A., Węglewski W., Kaszyca K., Rojek J., Chmielewski M., Thermal conductivity analysis of porous NiAl materials manufactured by spark plasma sintering: Experimental studies and modelling, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, ISSN: 0017-9310, DOI: 10.1016/j.ijheatmasstransfer.2022.123070, Vol.194, pp.123070-1-19, 2022

This work presents a comprehensive analysis of heat transfer and thermal conductivity of porous materials manufactured by spark plasma sintering. Intermetallic nickel aluminide (NiAl) has been selected as the representative material. Due to the complexity of the studied material, the following investigation consists of experimental, theoretical and numerical sections. The samples were manufactured in different combinations of process parameters, namely sintering temperature, time and external pressure, and next tested using the laser flash method to determine the effective thermal conductivity. Microstructural characterisation was extensively examined by use of scanning electron microscopy and micro-computed tomography (micro-CT) with a special focus on the structure of cohesive bonds (necks) formed during the sintering process. The experimental results of thermal conductivity were compared with theoretical and numerical ones. Here, a finite element framework based on micro-CT imaging was employed to analyse the macroscopic (effective thermal conductivity, geometrical and thermal tortuosity) and microscopic parameters (magnitude and deviation angle of heat fluxes, local tortuosity). The comparison of different approaches toward effective thermal conductivity evaluation revealed the necessity of consideration of additional thermal resistance related to sintered necks. As micro-CT analysis cannot determine the particle contact boundaries, a special algorithm was implemented to identify the corresponding spots in the volume of finite element samples; these are treated as the resistance phase, marked by lower thermal conductivity. Multiple simulations with varying content of the resistance phase and different values of thermal conductivity of the resistance phase have been performed, to achieve consistency with experimental data. Finally, the Landauer relation has been modified to take into account the thermal resistance of necks and their thermal conductivity, depending on sample densification. Modified theoretical and finite element models have provided updated results covering a wide range of effective thermal conductivities; thus, it was possible to reconstruct experimental results with satisfactory accuracy.

Słowa kluczowe:
thermal conductivity, porous materials, spark plasma sintering, micro-computed tomography, nickel aluminide, finite element modelling, tortuosity

Afiliacje autorów:
Nosewicz S. - IPPT PAN
Jurczak G. - IPPT PAN
Wejrzanowski T. - Politechnika Warszawska (PL)
Ibrahim S.H. - Politechnika Warszawska (PL)
Grabias A. - Lukasiewicz Institute of Microelectronics and Photonics (PL)
Węglewski W. - IPPT PAN
Kaszyca K. - Lukasiewicz Institute of Microelectronics and Photonics (PL)
Rojek J. - IPPT PAN
Chmielewski M. - Institute of Electronic Materials Technology (PL)

Abstrakty konferencyjne
1.  Chmielewski M., Kaszyca K., Strojny-Nędza A., Grabias A., Romelczyk-Baishya B., Rojek J., Nosewicz S., The experimental investigations of sintering kinetics of NiAl powder, AMT'2023, Advanced Materials and Technologies Conference, 2023-06-18/06-21, Wisła (PL), pp.1, 2023
2.  Nosewicz S., Jurczak G., Wejrzanowski T., Ibrahim S.H., Grabias A., Węglewski W., Kaszyca K., Rojek J., Chmielewski M., Numerical study of heat conduction of spark plasma sintered materials, CMM-SolMech 2022, 24th International Conference on Computer Methods in Mechanics; 42nd Solid Mechanics Conference, 2022-09-05/09-08, Świnoujście (PL), pp.1, 2022

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