Structural and Mechanical Changes of AlMgSi0.5_{0.5} Alloy during Extrusion by ECAP Method

SPD (several plastic deformations) methods make it possible to obtain an ultrafine-grained structure (UFG) in larger volumes of material and thus improve its mechanical properties. The presented work focuses on the structural and mechanical changes of aluminium alloy AlMgSi$_{0.5}$ (EN AW 6060) during processing by repeated extrusion through the ECAP rectangular channel. After a four-pass extrusion, the samples’ microstructures were observed using an optical microscope, where refinement of the material grains was confirmed. Tensile tests determined the extrusion forces and allowed interpretation of the changes in the mechanical properties of the stressed alloy. The grain size was refined from 28.90 μm to 4.63 μm. A significant improvement in the strength of the material (by 45%) and a significant deterioration in ductility (to 60%) immediately after the first extrusion was confirmed. The third pass through the die appeared to be optimal for the chosen deformation path, while after the fourth pass, micro-cracks appeared, significantly reducing the strength of the material. Based on the measurement results, new analytical equations were formulated to predict the magnitude or intensity of the volumetric and shape deformations of the structural grain size and, in particular, the adequate increase in the strength and yield point of the material

Investigation of the Properties of 316L Stainless Steel after AM and Heat Treatment

Additive manufacturing, including laser powder bed fusion, offers possibilities for the production of materials with properties comparable to conventional technologies. The main aim of this paper is to describe the specific microstructure of 316L stainless steel prepared using additive manufacturing. The as-built state and the material after heat treatment (solution annealing at 1050 °C and 60 min soaking time, followed by artificial aging at 700 °C and 3000 min soaking time) were analyzed. A static tensile test at ambient temperature, 77 K, and 8 K was performed to evaluate the mechanical properties. The characteristics of the specific microstructure were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The stainless steel 316L prepared using laser powder bed fusion consisted of a hierarchical austenitic microstructure, with a grain size of 25 µm as-built up to 35 µm after heat treatment. The grains predominantly contained fine 300–700 nm subgrains with a cellular structure. It was concluded that after the selected heat treatment there was a significant reduction in dislocations. An increase in precipitates was observed after heat treatment, from the original amount of approximately 20 nm to 150 nm

Investigation of the Properties of 316L Stainless Steel after AM and Heat Treatment

Additive manufacturing, including laser powder bed fusion, offers possibilities for the production of materials with properties comparable to conventional technologies. The main aim of this paper is to describe the specific microstructure of 316L stainless steel prepared using additive manufacturing. The as-built state and the material after heat treatment (solution annealing at 1050 degrees C and 60 min soaking time, followed by artificial aging at 700 degrees C and 3000 min soaking time) were analyzed. A static tensile test at ambient temperature, 77 K, and 8 K was performed to evaluate the mechanical properties. The characteristics of the specific microstructure were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The stainless steel 316L prepared using laser powder bed fusion consisted of a hierarchical austenitic microstructure, with a grain size of 25 mu m as-built up to 35 mu m after heat treatment. The grains predominantly contained fine 300-700 nm subgrains with a cellular structure. It was concluded that after the selected heat treatment there was a significant reduction in dislocations. An increase in precipitates was observed after heat treatment, from the original amount of approximately 20 nm to 150 nm

Influence of longitudinal cold rolling on the surface topography of low carbon structural steel

U radu je prikazana metoda procjene površine ploče formirane uzdužnim hladnim valjanjem, obavljenim pomoću valjaoničkog stana 210 DUO SVa. Izvedeni su pokusi na uzorcima niskougljičnih konstrukcijskih čelika, kako bi se utvrdio utjecaj dimenzije zrna materijala s obzirom na tehnološke parametre, a posebice s obzirom na redukciju valjanja i silu valjanja. Hrapavost površine ploča mjerena je na tri mjesta optičkim profilometrom MicroProf FRT. Zbog toga su ovi rezultati međusobno uspoređeni.The paper presents a method of surface evaluation of steel strips formed by longitudinal cold rolling, carried out by a rolling mill DUO 210 SVa. The experiments were performed on samples of low carbon structural steel in order to determine the impact of grain size of material with respect to technological parameters, particularly with respect to a rolling reduction and rolling force. Surface roughness of the steel strips was measured at three locations by an optical profilometer MicroProf FRT. These results were consequently mutually compared

Snímanie fyzikálních veličín vo vybraných technologických procesoch

Import 07/03/2016PrezenčníNeuvedenoNeuveden

Detekce procesu řezání kapalinovým paprskem

Import 26/11/2009PrezenčníNeuvedenoNeuveden

Rapid Chloride Permeability Test of Mortar Samples with Various Admixtures

This paper is focused on the permeability of cement composite samples with various admixtures. Permeability was examined by the rapid chloride permeability test due to the simple and relatively quick performance among the many methods. Permeability is one of the durability parameters considering the pore system of the composite structure. Ion diffusion provides information about inner pore structure by passing a charge through the sample. In real-life conditions, not only chlorides but also other ions can penetrate into the structure and cause corrosion. Various cement supplements were used as admixtures. The reference sample consisted of cement, fine sand, and water, while the rest of the samples consisted of 20% blast furnace slag, bypass dust, eggshells or recycled glass instead of the cement. The results showed lower permeability in samples containing blast furnace slag and eggshells and a higher charge passage in samples with recycled glass and bypass dust than for the reference sample

Raziskave vodno jedkanih površin s svetlobnim zaznavanjem

In this paper we describe the principle of a new method for the optical measurement of surfaces generated by abrasive waterjets. There measured parameters are defined and we determined the way of creating a database of the measured values, and the method for statistical and analytical processing of data for optimising the technology, improving the quality of output control, and studying the mechanism of disintegration interaction between the high-speed abrasive waterjet and the machined material

The use of glass from photovoltaic panels at the end of their life cycle in cement composites

This article deals with the use of photovoltaic panels at the end of their life cycle in cement composites. Attention is focused on the properties of cement composite after 100% replacement of natural aggregate with recycled glass from photovoltaic panels. This goal of replacing natural filler sources with recycled glass is based on the updated policy of the Czech Republic concerning secondary raw materials for the period of 2019-2022, which aims to increase the self-sufficiency of the Czech Republic in raw materials by replacing primary sources with secondary raw materials. The policy also promotes the use of secondary raw materials as a tool to reduce the material and energy demands of industrial production and supports the innovations and development of a circular economy within business. The research has shown that it is possible to prepare cement composite based on recycled glass from solar panels, with compressive and flexural strength after 28 days exceeding 40 MPa and 4 MPa. Furthermore, a possible modification of the cement composite with different pigments has been confirmed, without disrupting the contact zone.Web of Science1421art. no. 665

Utjecaj uzdužnog hladnog valjanja na topografiju površine niskougljičnog konstrukcijskog čelika

The paper presents a method of surface evaluation of steel strips formed by longitudinal cold rolling, carried out by a rolling mill DUO 210 SVa. The experiments were performed on samples of low carbon structural steel in order to determine the impact of grain size of material with respect to technological parameters, particularly with respect to a rolling reduction and rolling force. Surface roughness of the steel strips was measured at three locations by an optical profilometer MicroProf FRT. These results were consequently mutually compared.U radu je prikazana metoda procjene površine ploče formirane uzdužnim hladnim valjanjem, obavljenim pomoću valjaoničkog stana 210 DUO SVa. Izvedeni su pokusi na uzorcima niskougljičnih konstrukcijskih čelika, kako bi se utvrdio utjecaj dimenzije zrna materijala s obzirom na tehnološke parametre, a posebice s obzirom na redukciju valjanja i silu valjanja. Hrapavost površine ploča mjerena je na tri mjesta optičkim profilometrom MicroProf FRT. Zbog toga su ovi rezultati međusobno uspoređeni.Web of Science20470970