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The use of DSC curves and the Kronmüller theory to study the level of structural defects of Fe-based bulk amorphous alloys

Jeż Bartłomiej, Nabiałek Marcin

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144613

EN

This article presents the results of tests carried out on rapid quenched Fe-based alloys. The alloys were made using an injection-casting method. The actual structure of the alloys was also studied using an indirect method, based on H. Kronmüller's theorem. Based on analysis of the primary magnetization curves, in accordance with the aforementioned theory, it was found that Mo causes a change in internal regions associated with changes in the direction of the magnetization vector. The evolution of the thermal properties with increasing volume of Mo has been confirmed by the DSC curves. Addition of Mo, at the expense of the Nb component, results in changes to the crystallization process (i.e. the crystallization onset temperature and number of stages). The study showed that the addition of Mo at the expense of Nb reduces glass forming ability. Based on the DSC analysis, free volumes were determined for the alloys tested. These values were compared with the analysis of primary magnetization curves. It was found that the DSC curves can be used to indirectly describe the structure of amorphous alloys similar to the theory of the approach to ferromagnetic saturation. This approach is new and can be used by many researchers in this field.

2

Preliminary Study of Frequency-Variable Vibration Packing Fabrication for Atomized Metallic Particulate Fuel Using Surrogate Spherical Powder

Kim Ki-Hwan, Ha Seong-Jun, Park Sang-Gyu, Kuk Seoung-Woo, Park Jeong-Yong

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 4

1043--1047

EN

An alternative fabrication method for metallic fuel in Gen-IV reactor was introduced with vibration packing of nuclear fuel particles to facilitate remote fabrication in a hot cell and reduce the generation of long-lived radioactive wastes. Vibration packing experiments on metallic particulate fuel using a surrogate 316L stainless steel powder were done to investigate the packing density and the uniformity of the simulated fuel according to the filling method and the vibration condition. Metallic particulate fuel filled with a pre-mixed power over all particles had the highest packing fraction and the most uniform distribution among the filling methods. The vibration packing method showed that it could fabricate the metallic particulate fuel having uniform distribution of spherical fuel particles through the adjustment of the filling method of the metallic powder and the vibration condition of the metallic particulate fuel.

3

Microstructural Characterization of U-10wt.%Zr Fuel Slugs Containing Rare-Earth Elements Prepared by Modified Injection Casting

Lee Sang-Hun, Kim Ki-Hwan, Kuk Seoung-Woo, Park Jeong-Yong, Choi Ji-Hoon

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

953--957

EN

U-10wt.%Zr metallic fuel slugs containing rare-earth (RE: a rare-earth alloy comprising 53% Nd, 25% Ce, 16% Pr and 6% La) elements for a sodium-cooled fast reactor were fabricated by modified injection casting as an alternative method. The distribution, size and composition of the RE inclusions in the metallic fuel slugs were investigated according to the content of the RE inclusions. There were no observed casting defects, such as shrunk pipes, micro-shrinkage or hot tears formed during solidification, in the metallic fuel slugs fabricated by modified injection casting. Scanning electron micrographs and energy-dispersive X-ray spectroscopy (SEM-EDS) showed that the Zr and RE inclusions were uniformly distributed in the matrix and the composition of the RE inclusions was similar to that of a charged RE element. The content and the size of the RE inclusions increased slightly according to the charge content of the RE elements. RE inclusions in U-Zr alloys will have a positive effect on fuel performance due to their micro-size and high degree of distribution.

4

Surface Characterization of Metallic Fuel Slugs Prepared by Modified Injection Casting

Mun S.-U., Kim K.-H., Oh S.-J., Park J.-Y., Hong S.-I.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

1049--1053

EN

Metallic fuel slugs containing rare-earth (RE) elements have high reactivity with quartz (SiO2) molds, and a reaction layer with a considerable thickness is formed at the surface of metallic fuel slugs. The surface characterization of metallic fuel slugs is essential for safety while operating a fast reactor at elevated temperature. Hence, it is necessary to evaluate the surface characteristics of the fuel slugs so that chemical interaction between fuel slug and cladding can be minimized in the reactor. When the Si element causes a eutectic reaction with the cladding, it deteriorates the metallic fuel slugs. Thus, it is necessary to examine the characteristics of the surface reaction layer to prevent the reaction of the metallic fuel slugs. In this study, we investigated the metallurgical characteristics of the surface reaction layer of fabricated U-10wt.%Zr-Xwt.%RE (X = 0, 5, 10) fuel slugs using injection casting. The results showed that the thickness of the surface reaction layer increased as the RE content of the metallic fuel slugs increased. The surface reaction layer of the metallic fuel slug was mainly formed by RE, Zr and the Si, which diffused in the quartz mold.

5

Work on the modification of the structure and properties of Ti6Al4V titanium alloy for biomedical applications

Klimas J., Łukaszewicz A., Szota M., Laskowski K.

Archives of Materials Science and Engineering

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2016

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Vol. 78, nr 1

10--16

EN

Purpose: The paper attempts to improve the properties of Ti6Al4V titanium alloy by the using of the injection casting method with rapid cooling. The comparison of the structure and properties of the Ti6Al4V titanium alloy formed by two methods: the injection casting under pressure in two variants under air and vacuum with using a rapid cooling and purchased commercially were carried out. Design/methodology/approach: Samples were produced by two methods: unconventional casting by injection under pressure of gas or vacuum to copper mold with rapid cooling, and a traditional method for the production of titanium alloys in a form of a rod. To achieve the pursued objective the following tests were performed: microstructural observations – light microscope and SEM, corrosion resistance tests, microhardness tests – Vickers method. Findings: Microstructural observations showed that the Ti6Al4V titanium alloy produced by injection casting method under pressure with rapid cooling is able to produce extremely fine-grained layer and ductile core. That distribution of structures significantly affect on the improvement of a number of properties compared to commercially produced material. Moreover, during process increased corrosion resistance was observed. Those properties have a significant impact on the possibility of using that type of a production method and material in many areas of materials science related with medicine. Research limitations/implications: In the framework of the studies, tests using living tissues, which would allow to determine whether the produced material is biocompatible and does not cause inflammation, have not been conducted. Practical implications: The application of injection casting carries some complications, which mainly relate to quartz capillary where ingot is melted. Titanium as a reactive element strongly absorbs silicon out of the capillary causing changes in the chemical composition in the surface layer of the final element. Further studies will be attempted to use a different type of material wherein the alloy will be melted. Originality/value: The paper presents the improvement of the properties of materials produced under pressure by casting injection, compared to the same material produced by a commercial method.

6

Characteristics of titanium Grade 2 and evaluation of corrosion resistance

Klimas J., Łukaszewicz A., Szota M., Szota K.

Archives of Materials Science and Engineering

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2016

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Vol. 77, nr 2

65--71

EN

Purpose: The paper attempts to improve the properties of titanium Grade 2 by the use of the injection casting method with rapid cooling. Design/methodology/approach: Microstructural observations by using an optical microscope, microhardness studies, X-ray qualitative analysis as well as corrosion resistance tests were carried out. Corrosion resistance tests were conducted by measuring the open circuit potential and measuring the resistance to corrosion by the method of anodic polarization curves in a potential range close to the corrosion potential. Findings: Studies have shown that the application of the abovementioned preparation method affect the microstructure of the finished item. There has been a fragmentation of the structure and the formation of dendrites. Those changes have improved corrosion resistance and increase microhardness. There were no changes in the phase composition. Research limitations/implications: Studies were performed only in the Ringer's solution indicating a potential use of this material as a biomaterial. Further research should be conducted in more aggressive environments especially for the energy industry and chemical industry. Practical implications: The application of injection casting carries some complications, which mainly relate to quartz capillary where ingot is melted. Titanium as a reactive element strongly absorbs silicon out of the capillary causing changes in the chemical composition in the surface layer of the final element. The addition of silicon in the surface layer may affect on obtained results. Originality/value: Using the production method indicates its use in future in many industries.

7

Comparison of results obtained using the injection method of preparation of solid amorphous alloys with and without suction

Klimas J., Łukaszewicz A., Szota M., Nabiałek M., Dobrzańska-Danikiewicz A.

Archives of Materials Science and Engineering

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2014

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Vol. 67, nr 2

77--83

EN

Purpose: The study compares the structure and properties titanium alloy Ti-6Al-4V produced by injection method allowing the production of massive amorphous materials in two varies – with and without suction. Design/methodology/approach: Samples were produced form titanium alloy Ti-6Al-4V produced by injection method. Structures and properties were compared of the same alloy but with different conditions in production process – with and without suction. To achieve the objective perused the following tests were carried out: study of phase composition by X-ray diffraction, observation of microstructure by using optical microscope and SEM, study of surface geometry – roughness, abrasion resistance tests and microhardness tests. Results: Microstructural studies have allowed to observe that the titanium alloy Ti-6Al-4V produced by injection method in both varies – with and without suction during injection to copper mold, has structure partially crystalized – nanocrystalline. In structure occur the crystal nuclei and lack of arrangement and regularity. The study of microhardness showed 100 HV 0.1 units higher hardness value in the embodiment with suction in comparison to the variant without suction. Titanium alloy Ti-6Al-4V produced with suction has better abrasion resistance in comparison with same alloy without suction. Alloy produced with suction has lower development area. Originality/value: The paper presented studies of massive amorphous and nanocrystalline alloys produced by alternative method – injection casting in two variants – with and without suction. That kind of production allow produced alloys with same chemical composition as commercial but with far better properties.

8

Comparison of properties of Ti-6Al-4V titanium alloys producedby two methods: by continuous casting and injection casting, in aspect of medical applications

Klimas J., Szota M., Nabiałek M., Łukaszewicz A., Bukowska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

263--267

EN

Purpose: The paper presents a comparison of the structure and properties of titanium alloys Ti-6Al-4V produced by two methods: conventional and injection casting which allows obtaining solid amorphous alloys. Design/methodology/approach: Test samples are titanium alloys Ti-6Al-4V produced by two methods: conventional and injection casting. To achieve assumed objective the followed test were performed: phase composition by X-ray diffraction, microstructure observation was carried out, preformed to study the geometry of the surface – roughness and abrasion resistance measurements. Research limitations/implications: Observation of microstructures revealed that, titanium alloy Ti-6Al-4V produced by conventional method has a crystalline ordered structure which is typical for materials produced by continuous casting, while the titanium alloy produced by injection casting has a structure partially crystalline, and in most predominates amorphous structure which is characterized by a lack of order and regularity. Confirmation of structural studies were obtained diffraction records from qualitative X-ray analysis. Sample which was produced by continuous casting has higher rate of roughness than sample produced by injection casting. Titanium alloy produced by injection casting has higher rate of abrasion resistance than alloy produced by conventional casting. Higher roughness and higher abrasion resistance, these properties are beneficial for the process of fusion of the implant with the tissues in living organism, that same is desired in case when alloy will be used for biomedical applications. Originality/value: The paper presented study of solid amorphous alloys which were produced by injection casting. That kind of production allowed to achieve much better properties than for alloys produced by conventional method - continuous casting.

9

Comparative description of structure and properties of Ti-6Al-4V titanium alloy for biomedical applications produced by two methods: conventional (molding) and innovative (injection) ones

Klimas J., Szota M., Nabiałek M., Łukaszewicz A., Bukowska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

195--201

EN

Purpose: In paper characterized two methods produced titanium alloy: hitherto used in industry – conti-casting and innovative method of obtaining solid amorphous alloy by injection casting. The results of studies comparing the structure and properties of the alloy Ti-6Al-4V produced by both methods. Design/methodology/approach: Test samples were titanium alloy Ti-6Al-4V produced by two methods: conventional and injection. To achieve the objective pursued performed the following tests: microstructure observation was carried out, the analysis of mechanical properties (microhardness) and corrosion resistance tests were performed in Ringer’s liquid, which simulates the human body fluids. Findings: Microstructural study allowed to observe that titanium alloy T-6Al-4V produced by conventional method has crystalline ordered structure which is characteristic for materials obtained by drawing, with oriented grains and elongated in the direction of drawing. Same alloy produced by injection casting has amorphous structure with occurrences of the single-crystal seeds, that kind of structure has lack of order and regularity. The microhardness study showed, that titanium alloy Ti-6Al-4V produced by drawing has a hardness of less than twice for the same alloy produced by the injection. The corrosion tests conducted in an environment that simulates human body fluids, revealed showed that the materials made by injection have significantly corrosion potential than alloy obtained by drawing. Originality/value: The paper presents a comparative study of titanium alloy produced by drawing and massive amorphous alloy produced by unconventional method – injection casting. By the results proved that the alloy produced by injection has much better properties than alloy produced by drawing.