W. Pilarczyk

Structural, Magnetic and Crystallization Study of Fe-Based Bulk Metallic Glasses

The work presents the structural, thermal and magnetic properties analysis of Fe72B20Si4Nb4 bulk metallic glasses in as-cast state and crystallization study of bulk amorphous alloy after annealing process. The studies were performed on bulk metallic glasses in of rods form with diameter of 1,5 and 2 mm. The structure analysis of the samples in as-cast state and phase analysis of studied alloy after annealing process was carried out by the X-ray diffraction (XRD) methods. Mössbauer spectroscopy (MS) was also used to investigate the local structure for studied bulk metallic glasses. Thermal properties associated with glass transition, onset and peak crystallization temperatures was examined by differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained initial magnetic permeability and disaccommodation of magnetic permeability.

The Study of Local Structure of Amorphous Fe-Co-B-Si-Nb Alloy by Atomic Pair Distribution Function

The materials from Fe-Co-B-Si-Nb system have several interesting and useful properties such as high mechanical strength, abrasive and corrosion resistance and good electrical properties useful in many applications, for example: materials for sensors and precise current transformers. The aim of the presented work was to obtain Fe-based alloy in an amorphous state and examination atoms arrangement in its structure which has an influence on material properties. Multicomponent alloy with nominal composition of Fe37.44Co34.56B19.2Si4.8Nb4 was obtained by pressure die casting method in form of plate with thickness of d=1mm. The structure of rapidly solidified plate was examined by X-ray diffraction. This investigation revealed that the studied sample was amorphous. Based on experimental X-ray data the pair distribution function was calculated and discussion on possible atoms arrangement was carried out.

The influence of heat treatment on the structure and thermal properties of metallic glasses

This paper presents the structure and chosen properties of Fe-based ribbons with specified composition, after casting and heat treating. The aim of this work was to produce amorphous ribbons and study the influence of heat treatment on the structure and thermal properties before and after annealing. The base alloy ingot was prepared by induction melting of pure Fe, Co, B, Si and Nb elements in argon atmosphere. Then, the station for ultra-fast cooling of molten alloy with high vacuum pumps, designed for the production of metallic glasses in the form of ribbons by Bühler Melt Spinner SC was used. Also, the X-ray diffraction analysis system PANalytical X’Pert PRO was used. As-cast ribbons and metallic glasses after annealing were examined by differential scanning calorimetry (DSC) method, with the use of DSC822 Mettler Toledo. Annealing was done at different temperature. On the basis of obtained dependence, the glass transition temperature (Tg), onset crystallization temperature (onset—Tx) and peak crystallization temperature (peak—Tp) were determined. The supercooled liquid region (ΔTx), specific heat and the crystallization enthalpy (ΔH) were calculated as well. The microscopic observation of cross section of ribbons was carried out by means of the Zeiss Supra 35 scanning electron microscope. Based on experimental data, the discussion on the correlation between thermal properties, structure, annealing and future application was carried out.

Mechanical alloying of Fe-C alloys

In this article, the effect of chemical composition and time of high-energy milling on the average diameter of particles and grains of powder of Fe-C alloy is discussed. The mechanical alloying processes of the Fe-0,4% mass.C and Fe-6,67% mass.C alloys were conducted. The following investigations were carried out: XRD, SEM, TEM and laser distribution of size of particles method.