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Influence of spatial distribution and the type of material on the occurrence of bandgaps in phononic crystals

Garus Sebastian, Sochacki Wojciech, Kwiatoń Paweł, Nabiałek Marcin, Petrů Jana, Kubanek Mariusz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 3

art. no. e144609

EN

The study investigated the effect of the fill factor, lattice constant, and the shape and type of meta-atom material on the reduction of mechanical wave transmission in quasi-two-dimensional phononic structures. A finite difference algorithm in the time domain was used for the analysis, and the obtained time series were converted into the frequency domain using the discrete Fourier transform. The use of materials with large differences in acoustic impedance allowed to determine the influence of the meta-atom material on the propagation of the mechanical wave.

2

Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

Snopiński Przemysław, Król Mariusz, Pagáč Marek, Petrů Jana, Hajnyš Jiří, Mikuszewski Tomasz, Tański Tomasz

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

77--94

EN

This study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

3

Experimental Investigation of Cutting Forces in High-Feed Milling of Titanium Alloy

Petrů Jana, Drábek Lukáš, Hajnyš Jiří, Jurok Dalibor, Pagáč Marek, Měsíček Jakub

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 1

89--95

EN

Titanium super alloys are often used in the chemical and aerospace industries, especially because of financial savings, resulting primarily from cheaper operation of equipment. Machinability of titanium alloys is more difficult than that of other metals. In addition, the low thermal conductivity causes the alloy to stick to the cutting edge of the cutting tool, thereby causing it to become dull faster. The article deals with the experimental evaluation of cutting forces and the design of suitable cutting parameters for the machining of the UNS R56260 titanium alloy with high-feed milling technology. Testing was carried out in climb and conventional milling under different cutting conditions. The cutting components of forces Fx, Fy, Fz were measured and evaluated. The results of the measurements were processed into a graphical form and suitable cutting conditions were designed in terms of the acting cutting forces.

4

Surface microhardening studies on steels after high feed milling

Petrů Jana, Zlámal Tomáš, Špalek František, Čep Robert

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

222--230

EN

The paper deals with the impact of high-speed machining production methods on the integrity of component surfaces. One has to point out that cutting conditions during machining have a significant impact on the final properties of surface and subsurface layers of the workpiece. The conclusion summarizes and analyzes the achieved results of experimental activities on stainless austenitic steel 1.4301, hardened tool steel 1.2343 and high-speed steel 1. 3344 (ASP 2023). The results of the work experimental parts demonstrate the influence of cutting parameters on selected surface integrity ones, specifically strengthening the surface and subsurface layers. The performed experiments show that microhardness of a surface layer of the machined material can be influenced by suitable cutting conditions and other cutting process parameters.

5

Effect of the cutting tool geometry on the tool wear resistance when machining Inconel 625

Zlámal Tomáš, Hajnyš Jiří, Petrů Jana, Mrkvica Ivan

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 1

236--243

EN

The paper deals with the design of a suitable cutting geometry of a tool for the machining of the Inconel 625 nickel alloy. This alloy is among the hard-to-machine refractory alloys that cause very rapid wear on cutting tools. Therefore, SNMG and RCMT indexable cutting insert were used to machine the alloy. The selected insert geometry should prevent notch wear and extend tool life. The alloy was machined under predetermined cutting conditions. The angle of the main edge and thus the size and nature of the wear changed with the depth of the material layer being cut. The criterion for determining a more suitable cutting geometry was the tool’s durability and the roughness of the machined surface.

6

A choice of the optimum cutting ranges for cutting nozzles A-SD for selection of metallurgical material

Stančeková Dana, Rudawska Anna, Kulla Albert, Petrů Jana, Holubják Jozef

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 3

106--113

EN

On the market there are plenty of machines for cutting of steel via a mixture of oxygen and flammable gases. Various manufacturers provide several types of torches, cutting nozzles and other equipment in their product range. Cutting nozzles are a component that significantly affects quality of cutting based in set parameters. However, data from catalogues and manuals by manufacturers on cutting parameters of nozzles are rarely in use in real conditions. That is why optimum cutting conditions for cutting via nozzles A-SD made by RHONA were tested and the final results were compared with those in the catalogue for a proper use in practice.