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Microstructural Evolution of Sinter-Forged Fe-Cr-Mo-C Alloy Depending on Cu Addition

Oh Min Chul, Kim Moontae, Lee Jisung, Ahn Byungmin

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 2

539--542

EN

Pre-alloyed Astaloy CrLTM (Fe-1.5 wt% Cr-0.2 wt% Mo), a commercial Fe-based alloy powder for high strength powder metallurgy products, was sintered and hot forged with additions of 0.5 wt% C and 0~2 wt% Cu. To investigate the influence of various Cu contents, the microstructural evolution was characterized using density measurements, scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). Transverse rupture strength (TRS) was measured for each composition and processing stage. The correlation between Cu additions and properties of sinter-forged Fe-Cr-Mo-C alloy was discussed in detail.

2

The production attempt of Fe-Nb-B-Zr and Fe-Nb-B-Y system alloys by die pressure casting method

Pilarczyk W., Kucharczyk M.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

222-228

EN

Purpose: The purpose of this article was to investigate the possibility of the production of Fe-Nb-B bulk metallic alloys with additions of yttrium and zirconium elements. Furthermore, this paper tends to present the structure and selected properties of obtained alloys. In this article the influence of an argon atmosphere on casting process was observed too. Design/methodology/approach: The production attempts were performed on Fe-Nb-B-Zr and Fe-Nb-B-Y system alloys in form of a plate. Master alloy ingots with compositions of Fe72B22Y4Nb2 and Fe71(Nb0.8Zr0.2)6B23 were prepared by induction melting of pure Fe, Nb, B, Y and Fe, Nb, B, Zr elements in an argon atmosphere. The ingots have been crushed and then the investigated material was cast with and without a protective atmosphere. The investigated materials were cast in form of a plate with thickness of 1 mm. The structure analysis of the studied materials in as-cast state was carried out using X-ray diffraction (XRD) and microscopic observation. The thermal properties of the alloys were examined by DSC methods. The measurments of the hardness were performed with the Vickers method. Findings: The Fe-Nb-B-Y and Fe-Nb-B-Zr system alloys in form of a plate were produced by die pressure casting method. The investigation methods revealed that the studied as-cast alloys were crystalline. The structure of the obtained plates is rather fine-grained and there were not found any impurities and undesirable phases inside the materials. The results of calorimetric curves confirm that all tested samples are crystalline. Practical implications: To extend the potential applications of the Fe-based BMGs, amorphous alloys with larger critical sizes and better processability are required. The Fe-Nb-B-Zr and Fe-Nb-B-Y bulk metallic glasses obtained by die pressure casting method can be used for production of telecommunications devices, sensors or low-energy transformers. These materials exhibit excellent mechanical and soft magnetic properties. Originality/value: An overall presentation of an influence of the yttrium and zirconium additions on the attempt of forming Fe72B22Y4Nb2 and Fe71(Nb0.8Zr0.2)6B23 alloys. The chemical composition of these alloys was tested in our laboratory for the first time.

3

Investigation of the structure and properties of Fe-Co-B-Si-Nb bulk amorphous alloy obtained by pressure die casting method

Pilarczyk W., Nowosielski R., Babilas R., Sakiewicz P., Pilarczyk A.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

363--367

EN

Purpose: The main aim of this paper is investigation of the microstructure and thermal properties of selected Fe-Co-B-Si-Nb bulk amorphous alloy. Design/methodology/approach: The studies were performed on Fe-Co-B-Si-Nb alloy in form of rods with diameter of ø0=1.5 and ø=2 mm. Master alloy ingot with compositions of Fe37.44Co34.56B19.2Si4.8Nb4 was prepared by induction melting of pure Fe, Co, B, Si and Nb elements in argon atmosphere. The structure analysis of the studied materials in as-cast state was carried out using X-ray diffraction (XRD). The thermal properties: glass transition temperature (Tg), onset crystallization temperature (Tx) and peak crystallization temperature (Tp) of the as-cast alloys were examined by differential scanning calorimetry (DSC) method. The microscopic observation of the fracture morphology of studied amorphous materials in rods form with different diameter was carried out by means of scanning electron microscope (SEM), within different magnification. Findings: The Fe-based bulk metallic glasses in form of rod were successfully produced by die pressure casting method. The investigation revealed that the studied rods are amorphous. These materials exhibit good glass-forming ability. These tested rods with diameter of 1.5 and 2 mm exhibit similar characteristic temperatures (Tg, Tx, Tp). The exothermic peaks describing crystallization process of studied bulk metallic glasses are observed Morphology of cross section rods is changing having contact with copper mould during casting from smooth fracture inside rod to fine narrow dense veins pattern near to rod surface. These rods have smooth surface and metallic luster. The presented fractures are characteristic for metallic glasses. Practical implications: The success of production of studied Fe-based bulk metallic glasses is important for future practical application of those materials as elements of magnetic circuits, sensors and precise current transformers. Originality/value: The success formation and investigation of the casted Fe-based bulk metallic glasses. The chemical composition of Fe37.44Co34.56B19.2Si4.8Nb4 alloy in form of rod were tested first time.

4

Structure studies of Fe-based metallic glasses by Mössbauer spectroscopy method

Babilas R., Kądziołka-Gaweł M., Nowosielski R.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 45, nr 1

7--12

EN

Received 10.01.2011; published in revised form 01.03.2011 Purpose: The paper presents a structure characterization of selected Fe-based metallic glass in as-cast state. Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons. The amorphous structure of tested samples was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM) methods. Mössbauer spectroscopy method was applied to comparison of structure in studied amorphous samples with different thickness (cooling rates). Findings: The XRD, TEM and Mössbauer spectroscopy investigations revealed that the studied alloy in as-cast state was amorphous. Comparison of diffraction patterns of studied samples with different thickness showed the slightly narrowing of diffraction lines. The TEM observations also revealed a changing of image contrast of glassy ribbons with increase of sample thickness. The Mössbauer spectra presented broadened six line patterns characteristic to the structural disorder of amorphous ferromagnetic materials. The hyperfine magnetic field distributions for studied sample thickness indicated the existence components corresponding to the regions with different iron concentration (an iron-rich and an iron-poor surroundings). Practical implications: The Mössbauer spectroscopy is very useful method in studying the structural environment of Fe atoms on a nearest-neighbor length scale allowing the analysis of iron-containing phases. Originality/value: The obtained examination results confirm the utility of investigation methods in analysis of microstructure in function of sample thickness.

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Structure and properties of Fe-Cr-Mo-C bulk metallic glasses obtained by die casting method

Pilarczyk W., Nowosielski R., Januszka A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

80-87

EN

Purpose: The goal of this work is to investigate structure and properties of Fe54Cr16Mo12C18 alloy rods with different diameters obtained by the pressure die casting method. Design/methodology/approach: Master alloy ingot with compositions of Fe54Cr16Mo12C18 was prepared by induction melting of pure Fe, Cr, Mo, C elements in argon atmosphere. The investigated material were cast in form of rods with different diameters. Glassy and crystalline structures were examined by X-ray diffraction. The microscopic observation of the fracture morphology was carried out by the SEM with different magnification. The thermal properties of the studied alloy were examined by DTA and DSC method. Findings: These materials exhibit high glass-forming ability, excellent mechanical properties and corrosion resistance. Research limitations/implications: It is difficult to obtain a metallic glass of Fe54Cr16Mo12C18 alloy. The investigations carried out on the different samples of Fe54Cr16Mo12C18 bulk metallic alloy allowed to state that the studied ribbon was amorphous whereas rods were amorphous – crystalline. Originality/value: The formation and investigation of the casted Fe-Cr-Mo-C bulk materials and the study of glass-forming ability of this alloy.