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Among the known severe plastic deformation (SPD) techniques, one particular group can be defined as SPD processing of thin samples. Their distinctive feature is that one of the sample dimensions, namely the thickness, is much smaller than the other two dimensions. Examples include High Pressure Torsion and two recently developed techniques: the Cone-Cone Method and the High Pressure Tube Twisting.
In the present work, effects of loading scheme and strain reversal on structure evolution are studied by using high pressure torsion (HPT) and twist extrusion (TE) techniques. High purity aluminum (99.99%) was processed at room temperature up to a total average equivalent strain of ∼4.8 by TE and HPT with two deformation modes: monotonic and reversal deformation with a step of 12° rotation. It was
The evolution of texture in pure aluminum subjected to monotonous and reversal deformation in high-pressure torsion was first clarified. In a low-strain regime the texture development is similar for both deformation modes, while significantly different behavior is observed at high strain levels. The monotonously deformed materials showed typical torsion textures. In contrast, strain reversal resul
High purity Al (99.99%) was subjected to severe plastic deformation through twist extrusion at room temperature. Microstructures were examined for 1 pass and 4 passes on the cross section perpendicular to the longitudinal axis of billets using optical microscopy and electron back scatter diffraction analysis. It was shown that a vortex-like material flow was observed on the cross section and this
High purity Al (99.99%) is subjected to severe plastic deformation (SPD) at room temperature using a process of twist extrusion (TE). The microstructure evolution and the related change in microhardness are examined with respect to imposed strain. It is shown that subgrains develop after the first TE pass with a size of ∼1.6 μm and this size remains essentially the same for further application of
All the SPD techniques introduce reversal straining principally, but effects of the reversal deformation on structure evolution were not studied directly yet. In the present work, an attempt was made to manage structure in pure (99.99%) Al by strain reversal through high pressure torsion (HPT). Total accumulated deformation up to equivalent strain ∼8 was used. General trend of the grain refinement
Twist extrusion is a recently developed method of severe plastic deformation that principally uses torsion to generate high strains in a repeatedly extruded billet, while maintaining a constant cross-section. The method thus results in a deformation gradient across the billet section. To date, the grain refinement behaviour of alloys deformed by twist extrusion have only been investigated qualitat
Objectives: To assess the health-related quality of life (HRQOL) of patients with mucopolysaccharidosis (MPS) and their caregivers and to quantify the disease-related costs from a societal perspective. Methods: In the context of a multi-country study of rare diseases (BURQOL-RD project), a cross-sectional survey was performed among MPS patients in seven European countries. Data on demographic char
Spread extrusion (SE), proposed by the first author, is a direct extrusion with spread and without elongation. SE does not change the cross-sections of a workpiece so it may be used for multipass deformation in combination with Twist extrusion (TE). We investigate the plastic flow at the TE and SE. We show that a combination of TE and SE leads to mixing of the metal within the specimen.
Twist Extrusion (TE) is a process of severe plastic deformation (SPD) being developed by us during recent 5 years. Upon this time we published few papers on mechanics of the process and influence of the TE processing on materials structure and properties. Here we reported some results on application of the twist extrusion processing and made few general conclusions.
Microstructure and mechanical properties as well as thermal stability of commercially pure titanium VT1-0 subjected to severe plastic deformation by twist extrusion (TE) were studied before and after low-temperature annealing and cold rolling. TE leads to a refinement of structural fragments to sizes of less than 1 μm, enhancement of strength, and the appearance of strong anisotropy of mechanical
It was shown that of a fine α-phase was formed in the Hadfield steel after a cold plastic deformation to E = 50%. Nuclei of the ex-phase of deformed samples reduced the decomposition start temperature of the austenite by 180°C. Fine crystals of an α-phase nearly 30 nm in size, whose concentration was as high as ∼2.3%, were detected in a steel Fe 79.55Mn17Al3Co0.45 after a SPD to ε = 92%. A steel F
It is investigated UFG structure formation in CP Ti bulks processed by SPD (cold Twist Extrusion (TE), true strain e∼5.1, with the following Cold Rolling (CR), true strain e∼0.7). Evolution of microstructure and tensile mechanical properties in the CP Ti were investigated under room temperature. After the TE, in transversal section it is formed structure fragments with size less 1 μm. Strength inc
The information on a new method of severe plastic deformation viz. screw extrusion (SE) is presented. Various SE schemes are considered. Experience of realization of this process is described. Effect of SE on mechanical characteristics of technically pure titanium (VT1-0) is analyzed.
The new way for deriving severe plastic deformations (SPD) by the twist extrusion (TE) is offered and the new kinematically possible field of defrormation rates is proposed. The value of the accumulated deformation after one pass is calculated. The upper estimate for the quantity of toughness resource exhaust is carried out. That allows to estimate the maximum number of passes without specimen fai
During the last decade it has been shown that severe plastic deformation (SPD) is a very effective for obtaining ultra-fine grained (UFG) and nanostructured materials. The basic SPD methods are High Pressure Torsion (HPT) and Equal Channel Angular Extrusion (ECAE). Recently several new methods have been developed: 3D deformation, Accumulative Roll Bonding, Constrained Groove Pressing, Repetitive C
Objectives: Our goal was to provide data on the economic burden and health-related quality of life (HRQOL) of patients with cystic fibrosis (CF) and their caregivers in Europe. Methods: A cross-sectional study was carried out on adults and children with CF in eight European countries. Patients completed an anonymous questionnaire regarding their socio-demographic characteristics, use of healthcare
We present some experimental results describing microstructural evolution in commercially pure titanium during severe plastic deformation by twist extrusion (TE). In particular, we show that increasing the number of TE passes leads to the decrease of the grain size d in both orthogonal and parallel cross-sections of the work piece. For example, if in its original state titanium has d ∼ 25 μm, then
One of the most effective methods for obtaining bulk ultrafine-grained materials is severe plastic deformation that is typically done using equal channel angular pressing. In this work we describe and analyze a new method for obtaining severe plastic deformations proposed by the first author. The method is based on direct extrusion and was called "twist extrusion" The main idea of the method is to
