Numerical analysis of AZ61 magnesium alloy extrusion process by modified equal channel angular extrusion (ECAE) method

The paper presents the results of numerical modelling of AZ61 magnesium alloy hot deformation using modified ECAE method. The temperature-velocity conditions were analysed using FEM. The extrusion process was realised using the die with modified angular channel containing horizontal contracting zone in the material exit direction. The channels were arranged at right angle relatively to each other. The main aim of the numerical research was to determine the most favourable parameters of the extrusion that allow obtaining the products with good mechanical properties. The final product is a round rod that could be used as a material charge to further plastic deformation process

Theoretical and experimental analysis of the backward extrusion process with a rotational die of AZ31 alloy

In this work theoretical and experimental analysis of the backward extrusion with a rotary die of the AZ31 alloy has been performed. The modification of the classical extrusion was based on the use of a rotary die. The results of theoretical research have confirmed that the use of the modified backward extrusion causes the appearance of shear stress in deformed material, which could affects the activation of additional mechanisms of deformation. The numerical modelling of the rotating extrusion of AZ31 alloy has been conducted by using the computer program Forge®. The experimental tests were carried out in the conditions of the STD 810 torsion plastometer using newly designed tools

The theoretical and experimental analysis of the possibility of employing the groove rolling process for the manufacture of Mg/Al bimetallic bars

The paper presents the results of investigation into the possibility of employing the groove rolling process to produce round Mg/Al bimetallic bars. The feedstock were round 22,5 mm Mg/Al bars that had been produced using the explosive welding method. The average thickness of the aluminium layer amounted to 1,7 mm. The Mg/Al bars were rolled in the stretching rolling passes. The theoretical analysis was done using the Forge2011® computer program. Based on the theoretical and experimental analysis it has been found that one of the main rolling process parameters influencing the quality of bond between the bimetal components is the initial feedstock temperature

The analysis of the plastic deformation of two-layered magnesium – aluminium alloys (AZ31 – Al)

The paper presents the results of physical modelling of the plastic deformation of the two-layered AZ31 - Al alloys. The AZ31 - Al feedstock was produced using the diffusion bonding method. Heating under pressure led to the formation of a continuous layer of the intermetallic phases at the bond interface of AZ31 - Al. A compression test was used to determine the plastic deformation of the two-layered AZ31 - Al alloys. Based on the analysis of the investigation results it has been found that, as the strain rate decreases and temperature increases, the intermetallic phase yields, and a distinct thinning of the intermetallic phase layer has occurred in the zone directly affected by the anvil

Teoretska i eksperimentalna analiza Cu-Al bimetalnih šipki u procesu valjanja

In this study, the authors present the results of their theoretical and experimental analysis of the rolling process of Cu – Al bimetallic bars in elongation passes. The original bars were round aluminium bar, covered with copper layer. For theoretical tests, the Forge2008® computer program was used, based on FEM. The model simulated metal flow during rolling of bimetallic bars in oval – round passes. The results of the experiments were compared with the finite element calculations. The analysis demonstrated that an appropriate selection of shape and size of oval pass allows production of even distribution of the copper layer in the bimetallic roll products.O ovom su radu autori prezentirali rezultate teoretske i eksperimentalne analize procesa valjanja Cu-Al bimetalnih šipki pri istezanju. Originalne šipke su bile okrugle aluminijske šipke, sa bakrenim zaštitnim slojem. Za potrebe teorijskog istraživanja korišten je program Forge 2008, koji je baziran na MKE. Model simulira tečenje metala za vrijeme valjanja bimetalnih šipki u kružnim prolazima. Rezultati eksperimenta su uspoređeni s proračunom konačnih elemenata. Analiza pokazuje kako odgovarajući izbor oblika i veličine kružnog prolaza dopušta proizvodnju ili čak razdiobu bakarnog sloja na bimetalnim valjanim proizvodima

Analysis of the Thermal and Magnetic Properties of Amorphous Fe 61Co10Zr2.5Hf2.5Me2W2B20 (Where Me = Mo, Nb, Ni Or Y) Ribbons

The paper presents the results of structural and magnetic properties and thermal stability for a group of functional materials based on Fe61Co10Zr2.5Hf2.5Me2W2B20 (where Me = Mo, Nb, Ni or Y). Samples were obtained in the form of ribbons using melt-spinning method. The X-ray diffraction patterns of investigated samples confirmed their amorphous structure. Based on the analysis of DSC curves characteristic temperatures: glass forming temperature (Tg), crystallization temperature (Tx) and temperature range of the supercooled liquid ΔTx were determined. Small addition of transition metals elements has strong influence on magnetic and thermal parameters of studied materials. The comprehensive studies revealed that in terms of magnetic properties the Ni-addition resulted in highest reduction in coercivity and anisotropy field

AusTraits, a curated plant trait database for the Australian flora

We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge

Physical simulations of ultra-fine grained steel plate rolling using Gleeble 3800 machine

W pracy przedstawiono wyniki fizycznych symulacji procesu walcowania blach arkuszowych i taśmowych z konstrukcyjnej stali ultradrobnoziarnistej. Celem przeprowadzonych symulacji było określenie wpływu zastosowanego schematu odkształceń i temperatur na uzyskaną strukturę końcową materiału po ochłodzeniu do temperatury otoczenia. W badaniach dla wybranych analizowanych schematów odkształceń, zarówno w warunkach symulacji walcowania blach arkuszowych, jak i taśmowych zastosowano zróżnicowane warunki chłodzenia i określono optymalne parametry procesu, umożliwiające uzyskanie możliwie dużego rozdrobnienia ziarna ferrytu.The paper presents the results of physical simulation of the process of plate and strip rolling. The aim of the simulations of rolling of ultra-fine grained steel was to determine the effect of the applied deformation and temperature values flowchart on the final structure of the material obtained after cooling to ambient temperature. For different values of deformation and cooling patterns optimum process parameters were identified to obtain possible large refinement of ferrite grains

Ocena struktury oraz właściwości magnetycznych stopów amorficznych Fe73Me5Y3B19 (gdzie Me = Ti lub Nb)

The results of microstructure and magnetic properties studies of the amorphous Fe73Me5Y3B19 (where Me = Ti or Nb) alloys are presented The samples of the investigated alloys were produced in the form of ribbons with thickness of approximately 30 um by unidirectional cooling of the liquid material on a rotating copper wheel. Both investigated alloys, in the as-quenched state, were fully amorphous which was verified using a ‘Bruker’ X-ray diffractometer. Static hysteresis loops, measured using ‘LakeShore’ vibrating sample magnetometer (VSM), were typical as for soft magnetic ferromagnets. The Fe73Nb5Y3B19 and Fe73Ti5Y3B19 alloys were characterized by relatively high values of saturation of the magnetization (1.25 T and 1.26 T, respectively) and low coercivity field (16 A/m and 47 A/m, respectively). The core losses obtained for the investigated alloys were significantly lower than for commercially used FeSi transformer steels. Both alloys also exhibited excellent time and temperature stability of the magnetic properties (within the investigated temperature range), as confirmed by measurements of magnetic susceptibility and its disaccommodation.Celem pracy było zbadanie mikrostruktury oraz właściwości magnetycznych czteroskładnikowych stopów Fe73Me5Y3B19 (gdzie Me = Ti lub Nb) o strukturze amorficznej, otrzymanych techniką ultraszybkiego zestalania ciekłego stopu na miedzianym obracającym się bębnie. Strukturę odlanych taśm badano za pomocą dyfraktometru rentgenowskiego firmy "Bruker". Z pomiarów tych wynika, że obydwa czteroskładnikowe stopy w stanie po odlaniu były amorficzne. Statyczne pętle histerezy zmierzone przy użyciu magnetometru wibracyjnego (VSM) firmy "LeakeSchore", były typowe jak dla ferromagnetyków magnetycznie miękkich, a wytworzone stopy Fe73Nb5Y3B19 i Fe73Ti5Y3B19 cechowały się względnie wysoką magnetyzacją nasycenia (odpowiednio: 1.25 T i 1.26 T) i małym polem koercji (odpowiednio: 16 A/m i 47 A/m). Straty energii potrzebnej na jeden cykl przemagnesowania dla obydwu badanych stopów były znacznie mniejsze niż dla komercyjnie produkowanych stali transformatorowych FeSi. Wytworzone stopy wykazywały dobrą stabilność czasową oraz temperaturową właściwości magnetycznych (w wyznaczonym zakresie temperatur), któwą określono na podstawie pomiarów podatności magnetycznej i jej dezakomodacji

Increasing the Durability of Separating Rolls During Rolling Ribbed Bars in the Three-Strand Technology

The paper presents the results of investigations aimed at enhancing the durability of slitting passes in the process of three-strand rolling of 16 mm-diameter ribbed bars. Using the Forge2011® computer program, numerical modelling of the rolling process was carried out in order to examine the variations in band shape in individual rolling passes, to verify the correctness of the designed new slitting pass system, to determine the local strains in the rolled band, and then to determine the distribution of unit friction force work on the roll groove surface. From the obtained investigation results it was found that the application of the new roll pass design in stands 13-16 increased their durability in the rolling process by approx. 30%. The wear of the roll sets for the stands under examination after rolling out the annual 16 mm-diameter bar production volume was determined in the study. The obtained numerical modelling results were verified in experimental tests