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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
We present an experimental study of the kinematics of twist extrusion (TE) and show that TE has the following properties: (i) as in equal-channel angular pressing (ECAP), the mode of deformation in twist extrusion is simple shear. Unlike in ECAP, there are two shear planes; one of them is perpendicular and the other is parallel to the specimen axis. (ii) The following processes are present during
This study examines the long-run relationship between finance and economic growth in Sweden from the 1830s until the 1990s using recently developed econometric techniques for tests of cointegration. The role of investment, education and technological progress (patents) is accounted for as well in order to assess the relative importance of the development of the financial system for growth performaThis study examines the long-run relationship between finance and economic growth in Sweden from the 1830s to the 1990s using recently developed econometric techniques for tests of cointegration. The role of investment, education and technological progress (patents) is accounted for as well in order to assess the relative importance of the development of the financial system for growth performance
The present work deals with achieving improvement in the mechanical properties of SUS304L stainless steel through the application of a unique microstructure design termed as 'Harmonic structure', and establishing a co-relationship between various microstructural characteristics and mechanical properties. Harmonic structure essentially means a bimodal grain size distribution with a specific periodi
Aluminium-titanium (Al/Ti) composite sheets were fabricated via asymmetric accumulative roll bonding (AARB), which capitalises on additional shear to enhance plastic deformation. Multi-layers of Al alloy (AA1050) and commercially-pure Ti sheets were alternatively stacked and rolled-bonded with varied roll diameter ratios (dr) ranging from 1 to 2, for up to four passes. Annealing of selected compos
High-cyclic fatigue life in ultra-fine grained materials fabricated by equal channel angular pressing (ECAP) suffers from a specific shear texture induced during the fabrication as has been demonstrated in the present study on the example of pure copper. This texture promotes orientation of the easy glide crystallographic planes to be aligned parallel to the shear plane in ECAP. If specimens for t
