M. Szota

Influence of Solidification Speed on Quality and Quantity of Structural Defects in Fe61Co10Zr2.5Hf2.5Y2W2B20 Amorphous Alloy

The microstructure of Fe61Co10Zr2,5Hf2,5Nb2W2B20 amorphous alloy in the form of ribbons obtained by classical melt spinning and plates obtained by an induction suction method were investigated using X-ray diffraction. The type of structural defects were studied by analysis of the magnetization characteristics near ferromagnetic saturation of the sample. It was shown that the presence of structural defects is strongly correlated with sample thickness and production process. It was shown that ribbons with cooling rate between 105-106 K/s have point type defects, wires obtained with lower cooling rate between 101-102 K/s, have linear type defect (quasi-dislocation dipoles). crystallization.

An investigation into the effect of isothermal annealing on the structure (XRD), microstructure (SEM, TEM) and magnetic properties of amorphous ribbons and bulk amorphous plates

Abstract Test samples of the alloy Fe61Co10Y8W1B20 were fabricated in the form of both amorphous ribbons and bulk amor-phous plates. The structure, microstructure and magnetic properties of samples in the as-quenched state and after annealing were investigated. The aim of the paper is to show the effect of the thermal treatment on the structural changes occurring in the amorphous state. The thermal treatment, performed at well below the crystallisation temperature, did not cause crystallisation. In the investigated amorphous alloys it has been found that, after a specific thermal treatment, structural relaxation occurs in the presence of structural defects, such as quasidislocational dipoles. Also, supporting the microscopy investigations with measurements of the magnetic properties can be extremely beneficial for facilitating description of the real structure and properties of the amorphous alloys; further, this testing combination offers the possibility for designing the optimal application parameters for an alloy.

Characteristics of titanium Grade 2 and evaluation of corrosion resistance

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 Ringers 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.

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

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.

Application of computed tomography for an analysis of composite with fine dispersive reinforcement made of the Fe65Co10Ni3W2B20 alloy

Purpose: The paper presents the results of microstructure and mechanical properties of composites resulting from a combination of powders of metallic glasses with an epoxy resin (Epidian 100). The study was performed using computed tomography. Design/methodology/approach: The filler used was made of a Fe65Co10Ni3W2B20 amorphous alloy based on, showing in the state after the formation the soft magnetic properties. The aim of the study was to determine the effect of the fraction of the composite powders on the microstructure parameters (mean pore diameter and pore volume fraction) and the properties of the obtained composites. Findings: Based on the survey it was found out that size fraction used does not affect the value of the modulus of elasticity linear composites studied. It was also shown that the composites analysed in an attempt to compress the cross cracked grain boundaries. The influence fraction powders and change the share of the pore size depending on the fraction of the filler. Research limitations/implications: No studies of the magnetic properties determine the usefulness of these materials in the electronics industry. Practical implications: Practical implications are to size the test specimens in the limited range of tests. In the future, it is planned to produce samples with a larger diameter. Originality/value: The paper presents a new group of composites-based metallic glasses conditions characterised by good properties produced a simple and inexpensive method.

The surface structural and mechanical properties of the amorphous CO22Y54AL24 ribbon

The aim of this study was to manufacture amorphous Co22Y54Al24 alloy in a form of thin ribbons and to investigate their properties. The investigated ribbons were prepared by rapid solidification of molten metal on a rotating copper cylinder (melt-spinning). In order to obtain the material with amorphous structure, the cooling rate of the liquid alloy should vary in a range from 104 to 106 K/s. The microstructure studies were performed using X-ray diffractometery. The mechanical properties were investigated by metallographic studies, micro-hardness and tribological resistance tests moreover the surface roughness profile were analyzed. All studies were performed for two sides of tapes, since the differences in ribbons surface, related with manufacturing process, are clearly visible. The surface from the bottom (drum side) was glossy and from the top side it was shiny.