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J. Małecka

Abstract

This article presents the results of research on resistance to isothermal oxidation of Ti-46Al-7Nb-0,7Cr-0,1Si-0,2Ni alloy with AlCrN layer applied. The reference material was a Ti-46Al-7Nb-0,7Cr-0,1Si-0,2Ni alloy in initial state without any coating deposited. The protective coating was deposited by PVD process. Attempts at isothermal oxidation in air were performed at 900 and 950°C during 250h. Measurements of the samples’ mass were taken with the accuracy of 10-4 g. An analysis of the obtained results was made: chemical composition analysis, phase analysis of the deposited coating and chemical composition analysis of the alloy surface with the coating deposited after oxidation tests. In the case of the oxidation of alloy in initial state, pronouncedly higher mass gain and ”deferred” scale chipping was noticed. The deposited AlCrN coating significantly reduces spalling processes and makes for lesser mass gain of the oxidized alloy.

Open access

J. Małecka

Abstract

The paper presents research results of isothermal oxidation of Ti-25Al-12.5Nb alloy. Oxidation was carried out in 9%O2+0,2%HCl+0,08%SO2+N2 atmosphere at the temperature of 700 and 750 ºC.

Open access

J. Małecka

Abstract

The present paper deals with the analysis of the course of oxidation of the cyclic Ti-46Al-7Nb-0.7Cr-0.1Si-0.2Ni alloy in a hot air atmosphere in the temperature range of 875-975°C. The constant rates of the oxidation were determined (separately for the first and second stages of oxidation) and the energy of oxidation activation of the tested alloy was established. It was discovered that the oxidation process of the Ti-46Al-7Nb-0,7Cr-0.1Si-0.2Ni alloy develops according to the parabolic correlation, and it is only possible to determine the apparent energy of oxidation activation.

Open access

J. Małecka

ABSTRACT

This study presents the test results of Ti-20Nb-15Al alloy isothermal oxidation in air at 700°C with the consideration of the effect of annealing time on the condition of the surface layer. It was determined that, depending on the heating time, the surface of the tested alloy was characterized by a different colouring. This phenomenon was observed only at 700°C.

Open access

Joanna Małecka and Justyna Krzak-Roś

Abstract

This study presents the test results of Ti-46Al-7Nb-0.7Cr-0.1Si-0.2Ni alloy isothermal oxidation with regard to a coating of SiO2 deposited by the sol-gel method. The oxidation test was carried out in air at 900°C. The SiO2 coating is not an effective and stable diffusive barrier, which would considerably improve oxidation resistance of Ti-46Al-7Nb-0.7Cr-0.1Si-0.2Ni alloy.

Open access

Wit Grzesik, Joanna Małecka, Zbigniew Zalisz, Krzysztof Zak and Piotr Niesłony

Abstract

The tribological behavior of the PVD-TiAlN coated carbide inserts in dry sliding against two-phase (α-β) titanium alloy,Ti6Al4V grade, was investigated. A modified pin-on-disc device was used to conduct experiments under variable normal load and sliding speed. Scanning electron microscopy (SEM) and X-ray micro-analyses by EDS were applied for observations of wear scars and wear products. It was revealed that the increase of sliding speed contributes to decreasing the friction coefficient under a low normal force, whereas the increase of the normal loading causes the friction coefficient is less sensitive to changes in the sliding speed and its values are equal to μ = 0.26-0.34. The adhesive nature of wear along with severe abrasive action of the Ti alloy were documented.