The effect of severe plastic deformation by ECAP process on the microstructures and mechanical properties of the aluminium alloy EN AW 6082 produced by cold extrusion is investigated. In both states were evaluated the structural changes by light microscopy, the analysis particles in structures, by X-ray diffraction (XRD) in transmission mode by synchrotron radiation and mechanical properties. Severe plastic deformation leads to strengthening of investigated EN AW 6082 alloy but on the other hand the plasticity of ECAP-ed alloy decreases.

The paper deals with the corrosion properties and corrosion resistance of aluminium alloys types of AlCu (EN AW 2017), AlMgSi (EN AW 6012) and AlZn (EN AW 7075) with heat treatment T3 (solution treatment, forming and natural aging). The basic corrosion characteristics were quantified by measurement of corrosion potential measured against the saturated calomel electrode and weight losses of exposed samples in the environment of distilled water and in solution SARS. The samples of aluminium alloys were immersed in above-mentioned environments for one minute for a period of six months. Furthermore, an extra evaluation of corrosion of exposed aluminium samples was carried out by means of metallographic analysis. The exposed sample surfaces were evaluated using a microscope.

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

The paper analyses the influence of the strain rate on the behaviour of unalloyed steels with Re 210 – 550 MPa in the deformation process. It presents and analyses the results of the influence of the strain rate ranging from 10-3 to 2.5.102 s-1 on the yield point, the tensile strength, the elongation and the reduction of area. It analyses the non-homogeneity of development of plastic deformation from both the macroscopic and microscopic points of view, as well as the influence of the strain rate on the development of plastic deformation. Since the intensity of the influence of the strain rate on the properties of materials depends on their internal structure, the tested steels are divided into three groups based on their yield point and yield point to tensile strength ratio.

The paper is concerned with an analysis of utility properties of selected aluminium alloys, namely EN AW 6082 (AlSi1MgMn), EN AW 6061 (AlMg1SiCu) and EN AW 7075 (AlZn5.5MgCu) with different technology of hot processing. The alloys were hot processed to reach T3 condition (solution annealing, cold forming and natural aging) and to reach T4 condition (solution annealing and natural aging). The following parameters were subject to evaluation: microstructure and sub-structure, mechanical properties (strength and plastic characteristics stated in Table. 1) as well as fatigue properties of these alloys assessed during alternative symmetrical stress in torsion. The paper was aimed to study the affect of processing technology of three aluminium alloys on their utility properties in the conditions of tensile stress and cyclic stress in torsion.