Joanna Małecka

The article presents an analysis of the outcomes for AA2519 aluminum alloy exposed to variable loads. The variable loads were implemented with a strain control program consisting of incremental steps and increasing/decreasing multiple steps. Tests were conducted at higher and lower strain ranges and yielded lower (LFL test) and higher (HFL test) fatigue life, respectively. The values of plastic strain, cyclic modulus, cyclic yield strength, and fractography were analyzed. Based on the analysis of the test results, a criterion was established for the division of the tested fatigue properties into two parts for which the strength coefficient and strain hardening exponent were determined. An analytical description of the cyclic stress–strain curve for the entire range of results obtained from the LFL and HFL tests was proposed. Compared to other available models describing material properties, good compliance was obtained with the experimental results for both the LFL and HFL tests.

The study analysed samples made of tin-zinc-lead bronze RG7 after fatigue tests under cyclic torsion conditions. The behaviour of the material used in both mechanical and building structures was analysed. Samples made for various load levels were subjected to this analysis. Fatigue cracks during...

The automotive, aerospace and marine industries make extensive use of aluminum and its alloys to produce a wide variety of components. This prompts research work related to improving manufacturing processes using these materials. One of the main problems in this area is the durability of cutting tools. This article describes the results of tests on the wear of coated and uncoated carbide cutting tools during turning of EN AW 2007 aluminum alloy. The tests were carried out under dry conditions and at higher cutting speeds. On the face rake the VBB indicator (average width of flank wear), and on the rake face the KB indicator (crater width on the rake face) were evaluated. Only for the uncoated insert the break-in period, steady-state wear region and intensive wear was observed, and the limiting value of the VBB indicator was obtained after 36 minutes of tool life. The TiAlN+TiN coated insert, as well as TiCN achieved very short tool life periods of 16 and 24 minutes, respectively. Compared to the uncoated and TiCN coated insert, a VBB increase of about 170% was obtained for the TiAlN+TiN coated insert after 16 minutes. In contrast, an increase in the VBB of almost 60% was obtained for the TiCN coated insert after 24 minutes, compared to the uncoated insert. Compared to the uncoated insert, an increase of 12.1% in the KB value was obtained for the TiCN coated insert, and 18.2% for the TiAlN+TiN coated insert.

The work analyzes the fracture topography of composite specimens subjected to three-point bending - static and impact. Scanning electron microscopy was used for this purpose. The tests were performed for two different materials - polypropylene and polyamide PA6, each reinforced with...

The paper presents the results of fatigue tests of the 6060 aluminum alloy. The test material was taken from the profiles used for production of side windows and external doors of the passenger trains by the RAWAG company. The tests were carried out for cyclic loads with pure bending, pure...

The research presented in this paper concerns the assessment of the resistance to high-temperature oxidation behaviour of a Ti-46Al-7Nb-0.7Cr-0.1Si-0.2Ni alloy and the explanation of the role of niobium during oxidation processes. The basic problem concerned the evaluation of the resistance of the studied alloy to cyclic oxidation in an air atmosphere, with particular attention to the influence of temperature, surface roughness and cooling rate from heating temperature to room temperature. The issue analysed was the effect of niobium addition on the corrosion kinetics as a high-melting element causing improved oxidation resistance, contributing to the reduction in the oxidation rate.

This paper proposes a novel approach to assessing oxidation behavior of TiAlN coatings with defined stoichiometry on the rake and flank surfaces. This is based on the multi-parametric comparison of the oxidation effects detected on the coatings’ surfaces resulting from static diffusion couple tests. In this experimental study the diffusion couples consisting of Ti-based and Ni-based alloys and coated TiAlN cutting inserts are tested, respectively. The optimum oxidation temperature was determined by annealing the selected TiAlN coating in a high temperature chamber at temperatures: 700 °C, 800 °C, 900 °C and 1000 °C in air. Concurrently, the mass change and corresponding thickness of the Al₂O₃ oxidized layer were measured and computed. The comparison of oxides produced covers the surface morphologies, chemical elements and phases which were analyzed by means of SEM (scanning electron microscope), EDS (energy dispersive spectroscopy) and XRD (X-ray diffraction techniques). Additionally, scratch tests were performed to assess the penetration depth down to the substrate and coating failure mechanism after oxidation in diffusion couples. An acceptable similarity of Al₂O₃ films formed on the TiAlN coating surfaces in diffusion couples and machining processes was established.