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1

Effect of N,N’-bis(benzoic) 1,4-cyclohexanedicarboxylic acid dihydrazide on poly(L-lactide) crystallization

Lv Yang, Tan Ninghui, Zhang Hui, Cai Yanhua, Zhou Xiaoqin

Polimery

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2025

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Vol. 70, nr 6

402--410

EN

Effect of N,N’-bis(benzoic) 1,4-cyclohexanedicarboxylic acid dihydrazide (CADBH) on the crystallization of poly(L-lactide) (PLLA) was investigated. CADBH (0.4–3 wt%) was introduced into PLLA by melt mixing. DSC confirmed that PLLA crystallization depends on both CADBH content and cooling and heating rates. The minimum crystallization half-life (35.4 s) was obtained at 115°C with 3 wt% CADBH. However, a small addition of CADBH had an unfavorable effect on PLLA transparency.

PL

Zbadano wpływ dihydrazydu kwasu N,N’-bis(benzoilo) 1,4-cykloheksanodikarboksylowego (CADBH) na krystalizację poli(L-laktydu) (PLLA). CADBH (0,4–3 % mas) wprowadzano do PLLA w procesie mieszania w stopie. Metodą DSC potwierdzono, że krystalizacja PLLA zależy zarówno od zawartości CADBH, jak i szybkości chłodzenia i ogrzewania. Minimalny półokres krystalizacji (35,4 s) uzyskano w temperaturze 115°C przy zawartości 3% mas. CADBH. Jednak niewielki dodatek CADBH miał niekorzystny wpływ na przezroczystość PLLA.

2

Microstructure and features of thermal behavior of polymer composites based on polylactic acid and carbon nanotubes

Lysenkov Eduard A., Lysenkova Iryna P.

Composites Theory and Practice

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2025

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R. 25 nr 2

123-131

EN

This study investigates the thermal behavior of biodegradable polylactide (PLA) modified with multi-walled car bon nanotubes (MWCNTs), conducted to determine the influence of the nanofiller and the prehistory on the structural and phase transformations in the polymer matrix. Experimental samples with different MWCNT contents were analyzed using differential scanning calorimetry to determine the glass transition temperatures, melting and crystallization features, as well as light microscopy methods to study the morphology. The obtained data made it possible to trace the dynamics of thermal transitions in nanocomposites considering the thermal prehistory and to identify trends in the formation of the crystalline structure depending on the MWCNT concentration. The results of the study indicate a complex interaction between the nanofiller and the polymer matrix, which is of significant importance for the development of new functional materials based on PLA with improved heat-resistant and mechanical properties.

3

Wpływ intensywności chłodzenia oraz prędkości wyciągania pasma na postęp krzepnięcia stali w procesach ciągłego odlewania

Sołek Krzysztof

Inżynieria Materiałowa

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2024

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Vol. 45, nr 6

13--17

EN

Procesy ciągłego odlewania charakteryzują się zwiększoną wydajnością w stosunku do technologii odlewania do wlewnic, a także gwarantują zmniejszoną energochłonność produkcji stali w końcowym bilansie energetycznym. Jest to spowodowane wyeliminowaniem jednego z etapów produkcji w postaci walcowni slabing. Wydajność procesów ciągłego odlewania jest regulowana prędkością wyciągania pasma, która wymusza dostosowanie intensywności chłodzenia, tak aby uzyskać właściwy dla danej instalacji postęp procesu krzepnięcia. Podjęto próbę odpowiedzi na pytanie, jak zmienia się proces krzepnięcia wraz ze zmianą prędkości odlewania oraz intensywności chłodzenia. Badania wykonano dla wybranej stali niskowęglowej. W pracy oszacowano również stosunek procentowej zmiany parametrów chłodzenia do procentowej zmiany prędkości odlewania, co jest szczególnie istotne z punktu widzenia sterowania procesami ciągłego odlewania. Podstawowym celem pracy było pokazanie możliwości opracowania prostych map parametrów ciągłego odlewania wybranej stali, w strefie pod krystalizatorem, na potrzeby sterowania procesem.

PL

Continuous casting processes are characterized by increased efficiency compared to the technology of casting into ingot molds, and also guarantee reduced energy consumption of steel production in the final energy balance. This is due to the elimination of one production stage, in the form of the slabing mill. The efficiency of continuous casting processes is regulated by the speed of strip pulling, which forces the adjustment of the cooling intensity in order to obtain the progress of the solidification process appropriate for a given installation. This work was an attempt to answer the question of how the solidification process changes with the change of the casting speed and cooling intensity. The tests were performed for selected low-carbon steel. The work also estimated the ratio of the percentage change in cooling parameters to the percentage change in the casting speed, which is particularly important from the point of view of controlling continuous casting processes. The main objective of the work was to demonstrate the possibility of developing simple maps of continuous casting parameters of selected steel in the zone under the crystallizer for the purpose of process control.

4

Influence of Melt Properties on the Dendritic Structure of Steel Castings

Aftandiliants Y., Gnyloskurenko Svyatoslav, Meniailo H., Khrychikov V.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

5--13

EN

The paper presents the experimental results on the determination of melt parameters such as the energy of the boundary, contact angle, density and kinematic viscosity of low and medium alloy steels at different temperatures, as well as the dispersion of their dendritic structure in solidified castings. The analysis of the data obtained allowed revealing using mathematical models the influence of the chemical composition and temperature of melts on their properties and the dendritic structure of castings. It was established the variation of the melt parameters depending on the particular chemical elements of steels as C, Si, Mn, O, P, V, Cr. The established analytical dependences shown that increasing density and viscosity contributes to the dispersion of the dendritic structure and viscosity is of the major effect. The derived quantitative patterns allows to evaluate structure formation of cast structural low and medium alloy steels.

5

Rozkład wielkości kryształów nadzorowany przez agenta uczenia ze wzmocnieniem z wykorzystaniem czujnika tomografii hybrydowej w procesie krystalizacji

Niderla Konrad, Kłosowski Grzegorz

Przegląd Elektrotechniczny

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2023

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R. 99, nr 3

102--105

PL

W pracy opisano wykorzystanie uczenia ze wzmocnieniem w modelu Simulink do symulacji sterowania procesem krystalizacji. Przedstawiono również stanowisko akwizycji danych tomograficznych służące do sterowania rzeczywistym procesem krystalizacji zarządzanym agentem uczenia ze wzmocnieniem. Rekonstrukcja obrazu z systemu tomograficznego umożliwia agentowi uczenia ze wzmocnieniem uzyskanie dodatkowych danych w czasie rzeczywistym o stanie środowiska, co z kolei pozwoli kontrolerowi na prowadzenie procesu.

EN

This paper describes the use of reinforcement learning in the Simulink model to simulate the control of the crystallization process. A tomographic data acquisition workstation for controlling the actual crystallization process managed by a reinforcement learning agent is also presented. Reconstructing the image from the tomographic system allows the reinforcement learning agent to obtain additional real-time data about the state of the environment, which in turn will allow the controller to guide the process.

6

Effect of Milling Time on Crystallization Sequence and Microstructure of NiTi Alloys Produced Via High-Energy Ball Milling

Goryczka Tomasz, Dercz Grzegorz

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

1127--1135

EN

A 20 gram batch weight of NiTi alloy, with a nominal equiatomic composition, was produced by mechanical alloying with milling times of 100, 120, and 140 hours. The differential scanning calorimetry was used to analyze the progress of the crystallization process. The X-ray diffraction examined the crystal structure of the alloy at individual crystallization stages. The observation of the powders microstructure and the chemical composition measurement were carried out using a scanning electron microscope equipped with an energy-dispersive detector. After the milling process, the alloy revealed an amorphous-nanocrystalline state. The course of the crystallization process was multi-stage and proceeded at a lower temperature than the pure amorphous state. The applied production parameters and the stage heat treatment allowed to obtain the alloy showing the reversible martensitic transformation with an enthalpy of almost 5 J/g.

7

Influence of process parameters in removing wastewater impurities via progressive freeze crystallization

Mazzam A.A., Hamizlan H.A., Jamal Ikhsan I.Z.A.I., Bakar M.N.F., Ab Hamid F.H.

Archives of Materials Science and Engineering

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2023

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Vol. 119, nr 2

56--61

EN

Purpose: The research aims to investigate the effect of the process parameter of progressive freeze concentration to eliminate tricholorophenol in wastewater. Design/methodology/approach: A stainless steel crystallizer was used throughout the experiment. Simulated wastewater containing trichlorophenol (TCP) was used as a sample solution, and ethylene glycol was utilized as a coolant to induce the heat transfer at a very low temperature. Progressive freeze crystallization (PFC) is an approach to purify water by implementing the fundamental concept of difference freezing point. In short, the PFC system produces ice-crystal layer by layer on a cooled surface until it forms a large and single-crystal block, leaving the impurities in the mother liquor. Findings: It is established that operating time and initial concentration influence the PFC performance. The findings show that the intermediate operating time gave the highest removal of TCP in wastewater. Meanwhile, for the effect of initial concentration, it was discovered that the lowest initial concentration resulted in the best TCP reduction with high purity of the water was obtained. Research limitations/implications: The results can be complemented by studies of the effect of coolant temperature and solution movement. These two parameters are believed to potentially improve the PFC performance. Practical implications: The findings can be implemented to select the optimal operating condition to treat the wastewater, especially in the industrial area with hazardous TCP. Originality/value: The obtained results testify to the predominant influence of operating time and initial concentration on the PFC performance in eliminating TCP in wastewater.

8

Regularities of Crystallization Heat Release During Solidification of Alloyed Cast Irons

Aftandiliants Y., Gnyloskurenko S., Meniailo H., Khrychikov V., Lomakin V.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

110--117

EN

The chemical composition of alloys plays an important role at their crystallization and influences the solid phase formation, and thus, microstructure and properties. The present paper studies the release of the heat of crystallization of alloyed wear-resistant cast irons in order to determine the quantitative patterns of the chemical composition influence to the kinetics of crystallization. The differential thermal analysis was applied to get the data of heat release, its rate at cast iron temperature decrease. The normalized dependence of the amount of crystallization heat over time was obtained. The main temperature parameters were analyzed and four stages at irons crystallization were established and characterized with their duration and released heat. The multiple correlation analysis allowed considering a numerous physical and chemical factors and distinguishing their role at crystallization of irons. As a result, the quantitative regularities are determined of influencing the content of alloying elements, impurities and carbides on a heat and time of crystallization at the different stages of solidification, which are of great importance in developing alloyed irons with required quality and properties.

9

Effect of Iron Phases Crystallization on the Durability of the Bimetallic Connection Between Ring Inserts and the Piston Casting

Szucki Michał, Piątkowski Jarosław, Czerepak M.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 2

112--118

EN

The article presents the most important causes of the unstable connection between cast iron ring inserts and the silumin casting of an engine piston. It is shown that manufacturing defects are mainly related to the alfin processing of inserts in Al-Si alloy (the so-called AS9 alloy). Exceeding the permissible iron content in AS9 alloy causes the crystallization of brittle -Al5FeSi phases. Their unfavorable morphology and large size are the main reasons for the weakening of the diffusion connection between the inserts and the piston, causing an unacceptable proportion of defective products. The study presented in this work was conducted under industrial conditions on a population of 10.000 pistons. Quality control data, production parameters, as well as the micro- and macro-structures of the cast iron inserts, and the interface area between the inserts and the silumin piston, were analyzed. Material and technological solutions have been proposed to reduce the occurrence of casting defects at the insert-piston joint. This includes the introduction of so-called "morphological correctors" of the -Al5FeSi phases, reducing the possibility of gaseous impurities in the AS9 alloy and optimizing the temperature of the alfin alloy.

10

Crystallization of GX2CrNiMoCuN 25-6-3-3 Grade Alloy Cast Steel and its Microstructure in the As-cast State and After Heat Treatment

Wróbel Tomasz, Jurczyk Paweł, Baron Czesław, Nuckowski Paweł M.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

94--103

EN

The paper presents the results of research conducted in the field of crystallization and microstructure of duplex alloy cast steel GX2CrNiMoCuN 25-6-3-3 grade. The material for research was the above-mentioned cast steel with a chemical composition compliant with the relevant PN-EN 10283 standard, but melted at the lowest standard allowable concentration of alloying additives (some in short supply and expensive), i.e. Cr, Ni, Mn, Mo, Cu and N. The analysis of the crystallization process was performed based on the DTA (Derivative Thermal Analysis) method for a stepped casting with a thickness of individual steps of 10, 20, 40 and 60 mm. The influence of wall thickness was also taken into account in the cast steel microstructure testing, both in the as-cast state and after solution heat treatment. The phase composition of the cast steel microstructure was determined by using an optical microscope and X-ray phase analysis. The analysis of test results shows that the crystallization of tested cast steel uses the ferritic mechanism, while austenite is formed as a result of solid state transformation. The cast steel under analysis in the as-cast state tends to precipitate the undesirable σ-type Fe-Cr intermetallic phase in the microstructure, regardless of its wall thickness. However, the casting wall thickness in the as-cast state affects the austenite grain size, i.e. the thicker the casting wall, the wider the γ phase grains. The above-mentioned defects of the tested duplex alloy cast steel microstructure can be effectively eliminated by subjecting it to heat treatment of type hyperquenching.

11

Study on glass-forming ability and corrosion performance of Ca-based biomedical materials

Feng Jing, Wang Yue, Liu Dehua, Yhang Yong, Geng Guihong

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 4

93--101

EN

Stress shielding and the need for secondary surgery are the two major challenges faced by permanent metallic implants, and the emerging Ca-Mg-Zn calcium-based bulk amorphous alloys, with Young’s modulus comparable to that of human bone, good biocompatibility, and in vivo degradation, are highly promising materials for bioimplants. Few studies have been reported on the glass formation ability (GFA) and corrosion degradation behavior of Ca-Mg-Zn amorphous alloys in the human body. In this work, we discuss a study on Ca53+xMg20Zn27–x (x = 0, 2, 4, 6, 8, 10) alloys, focusing on changes in Zn content near eutectic points and their impact on microstructure and biological corrosion behavior. A copper mold spray casting method has been developed to prepare amorphous bar alloys and amorphous crystalline composite bar alloys with a diameter of 3 mm, which has been verified by X-ray diffraction, electrochemical treatment, and immersion tests. The experimental results demonstrated that the Ca3Zn and CaZn2 phases were precipitated in the 3 mm bar material Ca53+xMg20Zn27–x (x = 0, 2, 4), and Ca53+xMg20Zn27–x (x = 6, 8, 10) was completely amorphous. The Ca63Mg20Zn17 alloy showed the best glass-forming ability, while the Ca59Mg20Zn21 alloy exhibited superior corrosion resistance. Cytotoxicity experiments showed that Ca-Mg-Zn alloys have good biocompatibility and can be used as biomedical materials.

12

Wybrane zagadnienia biomineralogii

Pawlikowski Maciej

Przegląd Geologiczny

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2022

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Vol. 70, nr 11

834--839

EN

Biomineralogy is the science between mineralogy, biology, medicine and biochemistry. It is focused on problems concerning mineralization of tissue and organs of human, animals and flora. It concerns interaction between mineral and biological tissue, as well as between biochemical components of living organism. These processes are important for good functioning of organs and human life.

13

Considering semi-crystallinity in molecular simulations of mechanical polymer properties : using nanoindentation of polyethylene as an example

Fritz Susanne

Computer Methods in Materials Science

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2021

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Vol. 21, No. 1

35--50

EN

Molecular dynamic (MD) simulations have been used to investigate the response of semi-crystalline polymers in nanoindentation tests, using polyethylene (PE) as an example. To that purpose, semi-crystalline simulation boxes of linear PE with various chain lengths up to C2000 were created by homogeneous nucleation during the non-isothermal cooling of melts. The final crystallinity depended on the chain length and the cooling rate used and could be estimated using various parameters like density, fraction of bonds in trans conformation, and energy terms. The simulation boxes were transferred into surface models and subjected to nanoindentation tests using non equilibrium MD. This allowed the deformation behaviour of the material to be analysed directly. Strong dependencies on the crystallinity of the PE were found, which underlines the importance of considering crystallinity when investigating the mechanical properties of semi-crystalline polymers by means of simulations.

14

Thermal performances and optical property of poly(L-lactic acid) under the influence of N,N’-dodecanedioic bis(3-phenylpropionic acid) dihydrazide as a crystallization promoter

Yang Xiao-Yu, Zhao Li-Sha, Cai Yan-Hua, Zhao Jie, Wang Lin, Ma Xiao-Li

Polimery

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2020

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T. 65, nr 7-8

523--532

EN

Poly(L-lactic acid) (PLLA) as an important biodegradable polymer suffers from slow crystallization rate and poor heat resistance. An organic compound N,N’-dodecanedioic bis(3-phenylpropionic acid) dihydrazide (BHADD) was synthesized to evaluate its general influences on the physical properties of PLLA. The melt-crystallization process indicated that BHADD could serve as a heterogeneous nucleating agent for improving the crystallization of PLLA, and PLLA/1%BHADD exhibited the sharpest melt-crystallization peak located at the highest temperature, as well as an increase of cooling rate weakened the crystallization ability of BHADD-nucleated PLLA. And the final melting temperature also displayed the significant effect on the crystallization process of PLLA. For the cold-crystallization process, both BHADD concentration and heating rate affected the cold-crystallization behavior of PLLA/BHADD, the increasing of BHADD concentration caused the cold-crystallization peak to shift to the lower temperature; in contrast, a higher heating rate during heating leaded to the peak’s shift toward the higher temperature because of the thermal inertia. The melting behavior of PLLA/BHADD depended on the crystallization temperatures and heating rates, and the double melting peaks were attributed to the melting-recrystallization. Thermal decomposition experiment showed all PLLA/BHADD samples as the pure PLLA only exhibited one thermal decomposition stage, but PLLA/BHADD had a lower thermal stability than the pure PLLA. Additionally, the addition of BHADD seriously decreased the light transmittance of PLLA.

PL

Poli(kwas L-mlekowy) (PLLA) to ważny biodegradowalny polimer charakteryzujący się małą szybkością krystalizacji i słabą odpornością na ciepło. Dihydrazyd kwasu bis(3-fenylopropiono) N,N'-dodekanodiowego (BHADD) zsyntetyzowano w celu oceny jego wpływu na właściwości fizyczne PLLA. Przebieg procesu krystalizacji ze stopu świadczy o tym, że BHADD może służyć jako heterogeniczny środek zarodkujący zwiększający szybkość krystalizacji PLLA. Mieszanina PLLA/1% mas. BHADD wykazywała najostrzejszy pik krystalizacji ze stopu zlokalizowany w zakresie najwyższej temperatury, a jednocześnie większą szybkość chłodzenia osłabiającą zdolność krystalizacji PLLA zarodkowanej BHADD. Również końcowa temperatura topnienia w istotnym stopniu wpływała na proces krystalizacji PLLA. W procesie krystalizacji na zimno zarówno stężenie BHADD, jak i szybkość ogrzewania oddziaływały na zachowanie PLLA/BHADD podczas krystalizacji, zwiększenie stężenia BHADD powodowało przesunięcie piku krystalizacji na zimno w kierunku niższej temperatury, natomiast większa szybkość ogrzewania prowadziła do, spowodowanego bezwładnością cieplną, przesunięcia piku krystalizacji na zimno w kierunku wyższej temperatury. Zachowanie PLLA/BHADD podczas topnienia zależało od temperatury krystalizacji i szybkości ogrzewania, a drugi pik topnienia przypisano procesowi rekrystalizacji. Badany przebieg rozkładu termicznego świadczy, że wszystkie próbki PLLA/BHADD, tak jak czysty PLLA, wykazywały tylko jeden etap rozkładu termicznego, mieszanina PLLA/BHADD charakteryzowała się jednak mniejszą stabilnością termiczną niż czysty PLLA. Dodatek BHADD w znacznym stopniu zmniejszył przepuszczalność światła PLLA.

15

Depth dependent X-ray diffraction of porous anodic alumina films filled with cubic YAlO3:Tb3+ matrix

Serafińczuk Jarosław, Pawlaczyk Łukasz, Podhorodecki Artur, Gaponenko Nikolai, Molchan Igor, Thompson George

Optica Applicata

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2020

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Vol. 50, nr 1

127--134

EN

The presented paper deals with the measurement methodologies of the structural properties of porous anodic alumina (PAA) films filled with YalO3:Tb3+ composite using X-ray diffraction, atomic force microscopy and scanning electron microscopy. It shows that the deposited material does not uniformly fill the porous volume of the anodic alumina film and the part of it forms a thick layer on the PAA surface. The aim of this work is to show the differences in the XRD response obtained at different angles of incidence of the excitation beam for the PAA/YalO3:Tb3+ system. Furthermore, this simple approach enables separation of the signal from both regions on the surface and inside the PAA pores, providing more accurate data interpretation. It reveals that the crystallization of the material on the PAA surface and within the pores is different.

16

The effect of thermal treatment of the melt before crystallization on the structure and properties of castings

Kondratyuk S. Ye., Veis V. I., Parkhomchuk Z. V.

Archives of Materials Science and Engineering

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2020

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Vol. 104, nr 1

23--29

EN

Purpose: The aim of the proposed research is to investigate the influence of temperature and duration of isothermal melt processing on structural characteristics of castings in connection with technological background of charge metal. Design/methodology/approach: Ferrous and non-ferrous alloys were obtained by remelting a charge with a dispersion-structured structure (which was ensured by high- speed crystallization). Remelting was carried out at different temperatures of overheating of the melt over the liquidus with different isothermal exposure at these temperatures. Experimental castings were crystallized under normal conditions. It was studied a change of structure formation and mechanical characteristics depending on the temperature and duration of thermal treatment of the melt before crystallization. Findings: It is established that isothermal treatment of the melt at the overheating of the liquid metal above a certain equilibrium temperature of the micro-inhomogeneous melt (Te) causes a gradual loss of hereditary characteristics of the original charge metal, increase of the chemical homogeneity of the melt and the formation of crystallization and formation a corresponding change in the mechanical properties of castings. Research limitations/implications: The results can be complemented by studies of the effect of thermal treatment in the temperature range of crystallization. Practical implications: The results can be used to select the optimal heat treatment during remelting and, accordingly, the mechanical properties of the resulting casting. Originality/value: The obtained results testify to the predominant influence of temperature on the dispersion of the cast structure of steels, given the duration of technological operations of preparation and casting of steels in the manufacture of castings in industrial conditions.

17

The Crystallization of the AlSi9 Alloy Designed for the Alfin Processing of Ring Supports in Engine Pistons

Piatkowski J.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

65--70

EN

This article presents a study of the crystallization and microstructure of the AlSi9 alloy (EN AC-AlSi9) used for the alfin processing of iron ring supports in castings of silumin pistons. Alfin processing in brief is based on submerging an iron casting in an Al-Si bath, maintaining it there for a defined time period, placing it in a chill mould casting machine and immersing it in the alloy. This technology is used for iron ring supports in the pistons of internal combustion engines, among others. Thermal analysis shows that when the AlSi9 alloy contains a minimal content of iron, nucleation and increase in the triple α (Al)+Fe+(Si) eutectic containing the α -Al8Fe2Si phase takes place at the end of the crystallization of the double α (Al)+ß(Si) eutectic. Due to the morphology of the ”Chinese script” the -Al8Fe2Si phase is beneficial and does not reduce the alloy’s brittleness. After approx. 5 hours of alfin processing, the -Al5FeSi phase crystallizes as a component of the α+Al5FeSi+(Si) eutectic. Its disadvantageous morphology is ”platelike” with sharp corners, and in a microsection of the surface, ”needles” with pointed corners are visible, with increases the fragility of the AlSi9 alloys.

18

Phase Transformation Analysis of the Amorphous Mg72Zn24Ca4 Alloy

Lelito J.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

21--24

EN

The paper presents research of metallic glass based on a Mg72Zn24Ca4 alloy. Metallic glass was prepared using induction melting and further injection on a spinning copper wheel. The X-ray diffractometer and differential scanning calorimeter (DSC) were used to investigate the phase transformation of the amorphous ribbon. The heat released in the crystallization process, during isothermal annealing, based on the differential scanning calorimeter investigation, was determined to be 166.18 Jg-1. The effect of isothermal annealing temperature on the kinetics of the amorphous alloy crystallization process using differential scanning calorimeter was investigated. For this purpose, two isothermal annealing temperatures were selected. The incubation time decreases as the temperature of the isothermal annealing increases from 300 to 252 seconds. The same relationship is visible in the case of duration of the phase transformation, which also decreases as the temperature of the isothermal annealing increases from 360 to 228 seconds. The obtained results show a significant influence of isothermal annealing temperature on the degree of phase transformation.

19

Crystallization Behavior and Properties of Hypereutectic Al-Si Alloys with Different Iron Content

Deev V., Prusov E., Prikhodko O., Ri E., Kutsenko A., Smetanyuk S.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

101--107

EN

Understanding the influence of iron impurity on the formation of the structure and the properties of hypereutectic aluminum-silicon alloys are important for achieving the required quality of castings, especially those obtained from secondary materials. In the present work, the influence of different iron contents (0.3, 1.1, and 2.0 wt.%) on the crystallization process, microstructure and mechanical properties of the Al-15% Si alloy was studied. It is shown that the presence of iron impurity in the Al-15% Si alloy leads to increasing the eutectic crystallization time from 6.2 to 7.6 s at increasing the iron content from 0.3 wt.% to 1.1 wt.%, changing the structure of the alloy eutectic in the solid state. The primary silicon and β-Al5SiFe phase coexist in the structure of the Al-15% Si alloys at a temperature below 575°C in the range of iron concentrations from 0 to 2 wt.% in equilibrium conditions. In the experimental alloys structure, the primary crystals of the β-phase were metallographically detected only in the alloys containing 1.1 and 2 wt.% of iron impurity. Increase of the iron content up to 2 wt.% significantly reduces the mechanical properties of the Al-15% Si alloy due to the formation of large platelet-like inclusions of β-Al5SiFe phase.

20

Compacted Graphite Iron with the Addition of Tin

Gumienny G., Kurowska B., Fabian P.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

15--20

EN

The paper presents the effect of tin on the crystallization process, microstructure and hardness of cast iron with compacted (vermicular) graphite. The compacted graphite was obtained with the use of magnesium treatment process (Inmold technology). The lack of significant effect of tin on the temperature of the eutectic transformation has been demonstrated. On the other hand, a significant decrease in the eutectoid transformation temperature with increasing tin concentration has been shown. It was demonstrated that tin narrows the temperature range of the austenite transformation. The effect of tin on the microstructure of cast iron with compacted graphite considering casting wall thickness has been investigated and described. The carbide-forming effect of tin in thin-walled (3 mm) castings has been demonstrated. The nomograms describing the microstructure of compacted graphite iron versus tin concentration have been developed. The effect of tin on the hardness of cast iron was given.