Browsing by Subject "texture"

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Access status: Open Access ,
Analiza anizotropii właściwości mechanicznych stopu magnezu typu WE43
(Wydawnictwa AGH, 2023) Dudziński, Michał; Waląg, Michał; Kula, Anna
The article presents experimental work on the anisotropy aspects of the mechanical properties of WE43 alloy and technically pure magnesium (99.95%) obtained by hot extrusion. The experimental work includes structural and phase characterisation of as-extruded materials and uniaxial compression tests conducted parallel and perpendicular to the extrusion direction. Complementary studies of the macrotexture of materials before and after plastic deformation were carried out. Based on received results the degree of anisotropy of the mechanical properties of the tested materials was determined. The texture was identified as an important factor determining the activation of particular deformation mode of the materials after extrusion. Keywords: WE43 alloy, anisotropy, texture, compression test, microstructure
Access status: Open Access ,
Effects of asymmetric rolling with tilted material entry on texture and mechanical properties of aluminium
Byrska-Wójcik, Dorota Joanna; Ostachowska, Monika; Gibek, Julia; Wierzbanowski, Krzysztof; Wróbel, Mirosław; Błoniarz, Remigiusz; Baczmański, Andrzej; Kopyściański, Mateusz; Kalemba-Rec, Izabela
Wydział Inżynierii Metali i Informatyki Przemysłowej; Wydział Fizyki i Informatyki Stosowanej; Wydział Fizyki i Informatyki Stosowanej
Asymmetric rolling texture of aluminium alloy 1050 was examined both experimentally and numerically. The rolling asymmetry was realized using rolls with different diameters rotating with the same angular velocity and by varying inclination of the rolling strip (i.e., the flat and tilted entry of the rolled strip between rolls). The final, 84% reduction in the thickness was obtained after six consecutive rolling passes. Crystallographic texture variation over the rolled bar thickness was determined using X-ray diffraction and predicted using the Finite Element Method combined with two crystalline deformation models (i.e., the elasto-plastic and the elasto-viscoplastic ones). Textures predicted by both models, taking into account all deformation process parameters, are in good agreement with experimental results. The obtained results confirm the effect of texture modifications caused by the shear stress component, resulting in the shifts of selected texture maxima in the orientation space, and explain the observed texture distribution across the sample depth. The novelty of this work consist in examination of the role of the tilted material entry (besides a difference in rolls diameters) in homogenization of texture distribution in multi-pass asymmetric rolling. The rolling geometry process variants, recommended for the technological practice, are indicated.
Access status: Open Access ,
Mechanical properties and structure evolution of the AZ91 magnesium alloy after hot rolling and annealing
(2015) Sułkowski, Bartosz; Boczkal, Grzegorz
The AZ91 magnesium alloy was processed up to 87.5% of total thickness reduction in several thermodynamic routes, consisted of hot rolling and intermediate annealing. The hot-rolling process was performed at a high strain rate equal to 1.6 s−1 and at a temperature of 430°C. The intermediate annealing was performed at 430°C for 15 minutes after each route. It was found that, during hot rolling, the hardness of the material increased from 32 HV to 40 HV, and the structure investigations showed a huge amount of twins formed inside the grains (which were not observed after annealing). Tensile tests have shown strong anisotropy in mechanical properties of the “as-rolled” samples dependent onthe orientation between tension direction (TD) and rolling direction (RD). The samples with TD perpendicular to RD provedhigher ultimate tensile strength (UTS) and (on the other hand) worse plastic properties as compared to the samples with TD parallel to RD. The annealing has an effect on the reduction of mechanical properties anisotropy. X-ray investigations have shown texture changes from the basal type with the additional (0001) <1120> component for “as-rolled” samples to the texture with the main (0001) <1010> component for annealed samples. The texture changes had a great impact on the anisotropy of mechanical properties of the investigated AZ91 magnesium alloy.
Access status: Open Access ,
Structure and properties of hot-rolled and annealed AZ61 magnesium alloy
(2017) Sułkowski, Bartosz
Magnesium alloy AZ61 was processed by hot rolling up to a large thickness reduction (~89%) in several routes with intermediate annealing. The hot rolling process was conducted at 450°C and at a 1.5 s−1 strain rate. The structure and texture evolution as well as the mechanical properties during processing were investigated. The structure studies showed that, during the hot-rolling process, a large number of twins formed, which had an impact on the mechanical properties of the hot-rolled samples. After annealing for 15 minutes, the twins were no longer observed in the annealed samples, causing a significant decrease in hardness. Moreover, an investigation of the hardness showed that annealing for 15 minutes did not remove all of the hardening effects nor did the hardness of the annealed samples decrease to the value before hot rolling. The texture investigations showed that the texture of the hot-rolled samples was a typical basal-type texture. However, the basal pick was split into two tilted towards the rolling direction (RD). The texture changed during annealing while the new strong texture components evolved. The annealing led to an increased intensity of <1010>{1120} texture component and enhanced ductility. It was concluded that the texture changes observed in the present investigations may lead to the enhanced ductility of magnesium alloys and, therefore, help us design a deformation scheme for magnesium alloys consisting of several thermomechanical routes.
Access status: Open Access ,
Texture evolution in Mg during rolling with a change of deformation path - a modeling approach
(Wydawnictwa AGH, 2022) Sułkowski, Bartosz
The weakening of strong textures in Mg alloys is a crucial factor in obtaining good quality final products that are less anisotropic. Considerable attention has been focused on experiments to find the optimal chemical composition of alloys or processing conditions. However, to reduce time-consuming experiments, texture simulations can help in specifying future research directions. In the present work, the texture evolution in rolled Mg and its alloys was studied using the viscoplastic self-consistent model. The texture simulations presented in the study cover unidirectional rolling, reverse rolling, and cross rolling of Mg and its alloys to check if the change in deformation path has an impact on the activation of non-basal slip systems. The results obtained in the study may help to design the best processing technology and reduce the mechanical anisotropy of magnesium alloys. Slip systems such as basal, prismatic, and pyramidal were taken into consideration. To reflect the effect of alloying elements on hardening, different values for critical resolved shear stress were considered. Pole figures and slip system activity were investigated to understand the texture evolution during rolling as the deformation path changes. It was found that cross rolling may be the most effective processing technology to reduce strong textures during the rolling of Mg alloys. To activate non-basal systems, critical resolved shear stresses and the Schmid factor must be modified. The former can be changed by increasing the processing temperature, proper alloying elements, or change in the strain rate sensitivity; the latter by changing the deformation path.