This article deals with the analysis and comparison of the conditions for solid state welding during extrusions by means of numerical simulation. Numerical simulations made on four different matrices, such as square die without integrated extrusion and equal channel angular pressing (iECAP), porthole die whit one and four square profile. Maximum volume and distribution of effective strain, strain rate and shear stress was analyzing. The results show that during cold molding of chips there is mutual deformations of chips, which are rearranged and mechanically crimped. In the first phase of pressing occurs complete elimination of porosity. The square die with iECAP was extrusion force is 30% higher than porthole die. Maximum effective strain was calculated for the porthole die whit four square profile.

The main aim of this work is to point out on possibility of properties improving of the aluminium alloy EN AW 6082 (AlSi1MgMn) with an appropriate combination of pre-ECAP solution annealing, the application of the severe plastic deformation by ECAP technology (equal channel angular pressing) and post-ECAP artificial aging. The effect of the severe plastic deformation and artificial aging on the alloy structure was evaluated by metallographic analysis, and alloy mechanical properties by uniaxial tensile test at room temperature, the Vickers hardness and by tribology test of resistance to abrasive wear. As a result of strain hardening by severe plastic deformation it reaches the improvement in hardness (by 56%), strength characteristics (yield strength by 92%, tensile strength by 29%) and abrasion wear resistance is 28 %. Keywords: severe plastic deformation, tension test, aluminium alloys, wear IntroductionThe aluminium alloys belonging to 6XXX groups, which are widely used in structural applications, the construction industry, the automotive industry and architectural section as extrusions products [1]. AlSi1MgMn alloy is characterized by good mechanical properties, resistance to tribology (abrasion wear) and corrosion degradation, low density. Due to good tribological properties of alloy can be used in excellent application. These properties can be increased by strengthening mechanisms: alloying additives respectively heat treatment and the severe plastic deformation [2][3]. The AlSi1MgMn alloy is alloyed from the main elements namely magnesium and silicon. At higher magnesium content tends to increase strength properties of hardened alloy formation of Mg 2 Si phase. Silicon improves mechanical properties by changing the shape of the grain. Except of the main alloying elements, there are added the alloy chromium and manganese which form dispersion particles. These are larger than the other precipitates that can act as nucleation sites for strengthening precipitations, and have good thermal stability, which influences the recovery and recrystallization [4][5][6] Another way of improving the properties of the alloy is heat treatment (consisting of solution treatment, quenching in water, and a natural or artificial ageing treatment). From the

CuCrZr alloy was subjected to equal channel angular pressing method, belonging to the severe plastic deformation group, followed by heat treatment under different ageing conditions to optimize mechanical properties of the alloy. Before equal channel angular pressing, CuCrZr alloy was treated by solution annealing at temperature 1020 • C for 1 h. Afterwards, samples were pressed through an equal channel angular pressing die once at room temperature and subjected to artificial ageing under different conditions (200, 400, 450, 480 • C for 30, 60, 90, 120, 150 min). Optimization of the CuCrZr alloy was done through the study of mechanical properties and microhardness as a function of ageing temperature and time considering the progress in microstructural/substructural features.

The experimental and theoretical investigation deals with laser welding of automotive thin steel sheets. As tested materials were used Interstitial Free Steel (IF) from type of Hight Strength Low Alloy (HSLA) and the second is S420 steel (Micro-Alloyed Steel). Weld quality has been measured with the help of microhardness test and microstructure. Changes of properties of these materials were carried out by static conditions. The tensile properties of the welded samples have been set in the both longitudinal directions. The structure of welded joints these two materials were investigated by metallographic analysis. Metallographic analysis confirmed the formation of favourable structure of weld metal and heat affected zone. Obtained results showed that by laser welding it is possible to create the high quality welded joints with positive mechanical properties on used in automotive industry.

Abstract. This study reports on an investigation of factors affect the process of compacting Al chips which are used to direct scrap processing through the forward extrusion method. EN AW 6060 chips of different geometry and types were mainly used as the experimental material. The chips were compacted in a die with a vertical channel (10.3 mm in diameter). To provide a range of processing conditions, three different weights were selected and compacting was performed under five, different compacting pressures. The movement of the chips within the die during compacting was analysed through numerical simulations using Deform 2D software. Study of the compacting process optimal parameters for increasing the density and enhancing the density distribution were defined. The results from our study clearly show that optimal conditions are obtained when the proportion of D/h is 1/1.1. Moreover, it was recognized that in the process of small chips compacting, there was obtained lower density than in the case of large chips.

The study in this paper aimed on the corrosion properties of aluminium alloys used in the power industry. The corrosion characteristics were evaluated in the initial and state after severe plastic deformation of aluminium alloy AlZnMgCu. Due to the frequent interaction of fatigue failure accompanied corrosive failure (e.g. aircraft wings, turbine blades etc.) fatigue characteristics of selected alloy were evaluated. Standard corrosion characteristics such as corrosion potential, polarization resistance, corrosion rate and the corrosion products were evaluated for both states of an alloy in distilled water and SARS during exposition reaching 263 520 minutes.