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Polskiej Akademii Nauk


mgr inż. Fatima Nisar

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Ostatnie publikacje
1.  Kaszyca K., Marcin C., Bucholc B., Błyskun P., Nisar F., Rojek J., Zybała R., Using the Spark Plasma Sintering System for Fabrication of Advanced Semiconductor Materials , Materials, ISSN: 1996-1944, DOI: 10.3390/ma17061422, Vol.17, No.1422, pp.1-15, 2024

The interest in the Spark Plasma Sintering (SPS) technique has continuously increased over the last few years. This article shows the possibility of the development of an SPS device used for material processing and synthesis in both scientific and industrial applications and aims to present manufacturing methods and the versatility of an SPS device, presenting examples of processing Arc-Melted- (half-Heusler, cobalt triantimonide) and Self-propagating High-temperature Synthesis (SHS)-synthesized semiconductor (bismuth telluride) materials. The SPS system functionality development is presented, the purpose of which was to broaden the knowledge of the nature of SPS processes. This approach enabled the precise design of material sintering processes and also contributed to increasing the repeatability and accuracy of sintering conditions.

Słowa kluczowe:
spark plasma sintering, arc melting, semiconductor materials, half-Heusler, bismuth telluride, cobalt triantimonide, SHS, SPS

Afiliacje autorów:
Kaszyca K. - Lukasiewicz Institute of Microelectronics and Photonics (PL)
Marcin C. - inna afiliacja
Bucholc B. - IPPT PAN
Błyskun P. - inna afiliacja
Nisar F. - IPPT PAN
Rojek J. - IPPT PAN
Zybała R. - Politechnika Warszawska (PL)
2.  Nisar F., Rojek J., Nosewicz S., Kaszyca K., Chmielewski M., Evaluation of effective thermal conductivity of sintered porous materials using an improved discrete element model, POWDER TECHNOLOGY, ISSN: 0032-5910, DOI: 10.1016/j.powtec.2024.119546, Vol.437, pp.119546- , 2024

This work aims to revise and apply an original discrete element model (DEM) to evaluate effective thermal conductivity of sintered porous materials. The model, based on two-particle sintering geometry, calculates inter-particle neck using Constant Volume (CV) criterion. The model was validated using experimental measurements on sintered porous NiAl. For DEM simulations, heterogeneous samples with real particle size distribution and different densities were obtained by simulation of hot pressing. Neck size evaluated using Coble’s and CV models were compared to show that commonly used Coble’s model overestimates neck size and conductivity. The proposed model was improved by neck-size correction to compensate for non-physical overlaps at higher densities and by adding grain-boundary resistance to account for porosity within necks. Resistance contribution from grain boundaries was shown to decrease with increasing density. Thermal conductivity obtained from the improved model was close to experimental results, suggesting validity of the model.

Słowa kluczowe:
Discrete element method,Effective thermal conductivity,Porous materials,Sintering,Heat conduction simulation

Afiliacje autorów:
Nisar F. - IPPT PAN
Rojek J. - IPPT PAN
Nosewicz S. - IPPT PAN
Kaszyca K. - Lukasiewicz Institute of Microelectronics and Photonics (PL)
Chmielewski M. - Institute of Electronic Materials Technology (PL)
3.  Munawar A., Sadeeda ., Asif V., Jafri A., Nisar F., Wegener M., Su J., Kargl F., Effect of Undercooling on the Microstructure and Mechanical Properties of Hyper-eutectic Ni–Sn Alloy, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-023-07172-z, pp.1-9, 2023

In this study, container-less solidification of hyper-eutectic Ni–Sn alloy has been performed by using the electromagnetic levitation technique. The effect of undercooling on the formed microstructure and on the mechanical properties have been investigated. Growth velocities were determined by high-speed video-imaging of the solidification process. A step change in the growth velocities that are increasing with increasing undercooling is observed. This aligns with an observed first change in the microstructure between low and intermediate undercoolings. At the lower undercoolings, a pro-eutectic Ni3Sn phase along with lamellar eutectic structure in the inter-dendritic region is found. At intermediate undercooling of 100–150 K, a divorced eutectic microstructure is observed whereas at undercoolings above 165 K α-Ni precipitates are observed within β-Ni3Sn dendrites. Microhardness testing revealed higher strength for the lamellar phase as compared to the non-lamellar phase. Nano-indentation has been performed to determine the hardness and strength of individual phases in the microstructure.

Afiliacje autorów:
Munawar A. - inna afiliacja
Sadeeda . - inna afiliacja
Asif V. - inna afiliacja
Jafri A. - inna afiliacja
Nisar F. - IPPT PAN
Wegener M. - inna afiliacja
Su J. - inna afiliacja
Kargl F. - inna afiliacja
4.  Anwer Z., Umer Malik A., Nisar F., Hafeez Muhammad A., Yaqoob K., Luo X., Ahmad I., Microstructure and mechanical properties of hot isostatic pressed tungsten heavy alloy with FeNiCoCrMn high entropy alloy binder, Journal of Materials Research and Technology, ISSN: 2238-7854, DOI: 10.1016/j.jmrt.2022.12.078, Vol.22, pp.2897-2909, 2023

Microstructural development and mechanical properties of tungsten heavy alloy, WHA, with FeNiCoCrMn high entropy alloy, HEA, binder were investigated and compared to conventional WHA using Fe–Ni binder. Both WHAs, with HEA and conventional Fe–Ni binders, were fabricated by hot isostatic pressing at a temperature of 1450 °C in an argon environment. Scanning electron microscopy revealed that WHA with HEA and conventional binders possessed uniform and well-refined microstructures. Energy dispersive spectroscopy and X-ray diffraction, XRD, spectroscopy validated the formation and composition of HEA, existing as a skeletal network surrounding tungsten grains. HEA binder exhibited an overall increase of 42% in micro Vickers hardness values. Furthermore, hardness values of the tungsten heavy alloy were also seen to rise when fabricated with HEA binder. However, WHA sample with HEA binder was seen to undergo faster strain hardening and a premature failure, leading to lower values of ultimate strength and reduced ductility.

Słowa kluczowe:
Tungsten heavy alloys, High entropy alloys, Hot isostatic pressing, Liquid phase sintering

Afiliacje autorów:
Anwer Z. - inna afiliacja
Umer Malik A. - inna afiliacja
Nisar F. - IPPT PAN
Hafeez Muhammad A. - inna afiliacja
Yaqoob K. - inna afiliacja
Luo X. - inna afiliacja
Ahmad I. - inna afiliacja

Abstrakty konferencyjne
1.  Nisar F., Nosewicz S., Kaszyca K., Chmielewski M., Rojek J., Discrete element simulation of heat flow in porous materials manufactured by FAST/SPS, NUMIFORM 2023, the 14th International Conference on Numerical Methods in Industrial Forming Processes, 2023-06-25/06-29, Kraków (PL), pp.1, 2023
2.  Rojek J., Nisar F., Nosewicz S., Chmielewski M., Kaszyca K., Coupled thermo-electrical discrete element model of electric current activated/assisted sintering, PARTICLES 2023 - The VIII International Conference on Particle-Based Methods, 2023-10-09/10-11, Milan (IT), pp.1, 2023
3.  Rojek J., Nisar F., Nosewicz S., Chmielewski M., Kaszyca K., DISCRETE ELEMENT MODELLING OF MULTIPHYSICS PHENOMENA IN POWDER SINTERING PROCESSES, COMPLAS 2023, XVII International Conference on Computational Plasticity. Fundamentals and Applications, 2023-09-05/09-07, Barcelona (ES), pp.1, 2023
4.  Nisar F., Rojek J., Nosewicz S., Chmielewski M., Kaszyca K., Thermo-Electric Model for FAST/SPS Sintering in Discrete Element Framework, FAST/SPS, 2nd Conference on FAST/SPS From Research to Industry, 2023-10-16/10-18, Warszawa (PL), pp.56-57, 2023

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