Wyniki wyszukiwania - Biblioteka Nauki

1

Assessment of the feasibility of determining the volume fraction and characteristics of the size, shape and distribution of γ’ phase precipitates in nickel-based superalloys

100%

Szczotok A.

Technical Transactions

|

2023

|

tom Vol. 120, iss. 1

art. no. e2023011

EN

This overview presents a comprehensive exploration of the research methodsemployed for the precise assessment of volume fraction and the detailedcharacterisation of the size, shape and distribution of γ' phase precipitates withinNi-based superalloys. These advanced materials exhibit exceptional mechanicalproperties due to the presence of γ' precipitates. The accurate quantification ofprecipitate parameters is crucial for understanding material behaviour and forthe optimisation of alloy design. In this overview, a spectrum of techniques,including microscopy (SEM, TEM), diffraction (XRD), spectroscopy (EDS, EELS)and advanced imaging (3D-APT, STEM-HAADF, FIB-SEM) is discussed. Strengths,limitations and potential synergies among these methods are highlighted, offeringresearchers a comprehensive toolbox to advance their investigations of γ' phaseprecipitates in Ni-based superalloys.

2

The influence of prosthetic elements manufacturing technology on properties and microstructure shaping Co-Cr-Mo alloys

63%

Augustyn-Nadzieja J. , Szczotok A.

Engineering of Biomaterials

|

2020

|

tom Vol. 23, no. 156

24--31

EN

The presented publication discusses the test results regarding samples of a prosthetic alloy from the Co-Cr-Mo system. The test samples were obtained by means of two different methods applied in prosthetics laboratories to compare their properties and microstructure. To obtain the samples via the traditional lost wax casting method, the cast alloy Co-Cr-Mo was used, commercially known as Wironit LA. In the case of the modern technique DMLS (Direct Metal Laser Sintering), metallic powder Co-Cr-Mo, called EOS Cobalt Chrome MP1, was used. The samples of both Co-Cr-Mo alloys obtained via the two methods were prepared for metallographic tests; they also underwent microstructural observations with the use of light microscopy (LM) and scanning electron microscopy (SEM), and next they were subjected to hardness tests. The obtained samples demonstrated a dendritic structure. In the samples cast with the lost wax casting method, a segregation of the chemical composition was revealed. The samples obtained by means of the DLMS method were characterized by chemical composition homogeneity. The hardness measurements with the statistical analysis of the measurement results showed a difference between the examined alloys. On the basis of the performed studies, it was stated that the applied methods of manufacturing prosthetic elements make it possible to obtain diversified microstructural and mechanical properties of the alloys. The hardness value significantly affects the subsequent mechanical and finishing treatment of prosthetic elements, such as metal bases of crown caps, bridges, mobile prostheses or other retention elements.

3

Assessment of mechanical strength and corrosion resistance at variable pH of orthodontic wires

63%

Augustyn-Nadzieja J. , Szczotok A.

Engineering of Biomaterials

|

2020

|

tom Vol. 23, no. 157

2--9

EN

Orthodontic wires are components of fixed appliances used to perform the necessary tooth movements in the course of the orthodontic treatment. A variety of materials e.g. metals, alloys, polymers and composites are used to produce orthodontic wires. This study examined the mechanical strength and cracks resistance of three different types of wires, i.e. made of: austenitic steel grade AISI 303, NiTi alloy and Tiβ alloy. Corrosion processes are regarded to have a harmful effect on the properties of orthodontic wires, such as their strength, biocompatibility and aesthetic appearance. In this study, we investigated the corrosive behaviour of the wires in the artificial saliva solutions with varied pH simulating the natural oral cavity environment. It was demonstrated that the orthodontic rectangular wires made of austenitic steel grade AISI 303 exhibited the highest tensile strength. The NiTi alloy wires exhibited the best plastic properties of all the examined samples. In the case of electrochemical tests (changes in corrosion potential over a period of 24 h), the wire made of austenitic steel and the NiTi alloy wire reached a stable level of the stationary potential in the acidic environment. For the wires made of Tiβ, the highest stationary potential was observed in the alkaline environment. Additionally, the Tiβ alloy wire revealed the broadest passivation area in the specified potential scope.