The Tungsten Inert Gas (TIG) welding processes one of the prevalent methods used for welding aluminum alloys. TIG welding is most commonly used due to its superiority in welding less dense materials. The most prevalent issues encountered with TIG welding aluminium alloys are porosity creation and cracking due to solidification, both of which result in lower mechanical properties. Because of the metal’s susceptibility to heat input, this occurs. The current work is the result of a desire to improve the mechanical properties of dissimilar aluminium metals: AA5052-H32 & AA5083-H111. The process parameters of TIG welding are optimized towards eliminating the previously discussed failure scenarios. Various optimization techniques exist towards obtaining optimizing processes such as Response Surface Methodology (RSM), Genetic Algorithm (GA), Artificial Neutral Network (ANN), Flower pollination algorithm, Taguchi method etc, The Taguchi method was chosen for the optimization of process parameters due to its inherent nature of solving problems of singular variance. The optimal parameters combination was determined i.e. welding current at 170 A, filler rod diameter 2.4 mm and Gas flow rate of 11 lpm. The optimized input parameter was used to TIG weld the confirmation specimen which are further investigated for mechanical and metallurgical characterizations. The parameters were optimized and the results indicate that the input current was found to be the most contributing towards improving mechanical properties over all the process parameters.

Popular statistical techniques, such as Spearman's rank correlation matrix, principal component analysis (PCA) and multiple linear regression analysis were applied to analyze a large set of water quality data of the Rybnik Reservoir generated during semiannual monitoring. Water samples collected at 9 sampling sites located along the main axis of the reservoir were tested for 14 selected parameters: concentrations of co-occurring elements, ions and physicochemical parameters. The aim of this study was to estimate the impact of those parameters on inorganic arsenic occurrence in Rybnik Reservoir water by means of multivariate statistical methods. The spatial distribution of arsenic in Rybnik Power Station reservoir was also included. Inorganic arsenic As(III), As(V) concentrations were determined by hydride generation method (HG-AAS) using SpectrAA 880 spectrophotometer (Varian) coupled with a VGA-77 system for hydride generation and ECT-60 electrothermal furnace. Spearman's rank correlation matrix was used in order to find existing correlations between total inorganic arsenic (AsTot) and other parameters. The results of this analysis suggest that As was positively correlated with PO43-; Fe and TDS. PCA confirmed these observations. Principal component analysis resulted in three PC's explaining 57% of the total variance. Loading values for each component indicate that the processes responsible for As release and distribution in Rybnik Reservoir water were: leaching from bottom sediments together with other elements like Cu, Cd, Cr, Pb, Zn, Ni, Ca (PC1) and co-precipitation with PO43-, Fe and Mn (PC3) regulated by physicochemical properties like T and pH (PC2). Finally, multiple linear regression model has been developed. This model incorporates only 8 (T, pH, PO43-, Fe, Mn, Cr, Cu, TDS) out of initial 14 variables, as the independent predictors of total As contamination level. This study illustrates the usefulness of multivariate statistical techniques for analysis and interpretation of complex environmental data sets.

In this paper, the microstructure of laser beam welded Sc-modified AA2519-F has been taken under investigation. The welded joint has been produced using Fanuc 710i industrial robot equipped with YLS-6000 6 kW laser beam source. The welding speed and laser power were equal to 0.75 m/min and 3.2 kW, respectively. The investigation involved microstructure observations with the use of both light microscope and scanning electron microscope with energy dispersive spectroscopy (EDS) analysis of chemical composition and microhardness distribution measurements. It has been stated that laser beam welding allows to obtain Sc-modified AA2519-F weld of good quality, characterized by the presence of an equiaxed grain zone containing scandium-rich precipitates adjacent to the fusion boundary.

Severe Plastic Deformation (SPD) techniques have been used by researchers for last three decades in order to obtain Ultra-Fine Grained (UFG) materials. Equal Channel Angular Pressing (ECAP) is preferred more than other SPD techniques thanks to its high performance and practicability. Hexa Equal Channel Angular Pressing (Hexa-ECAP) – modified ECAP technique which enables to apply ECAP routes for cylindrical samples properly – was preferred in this study. Within the objective of this study, the effects of coefficient and ram velocity on the mean effective strain and strain inhomogeneity of Hexa-ECAP processed Al7075 aluminium alloy were investigated. Also, the effects of ram velocity and friction coefficient on hardness homogeneity were investigated benefitting from the similarity between the hardness distribution and the strain distribution.

The zinc and lead industry generates substantial quantities of waste. Among the many types of wastes, such as dust or liquid, a large proportion are solid waste such as slags. The purpose of the study was the qualitative and quantitative assessment of the short rotary kiln slags and slags deposited in a hazardous waste landfill originating from zinc and lead metallurgy. This assessment represents the primary step in evaluating materials such as slags concerning their potential for substantial applications, such as process for metal separation. Additionally, this evaluation forms the basis for a comprehensive environmental study. The concentrations of the four predominant metals – Fe>Pb>Zn>Cu – and accompanying elements – Na>Ca>K>Ni>Mn>Cr – were determined using atomic absorption spectroscopy (AAS) after aqua regia digestion. A large variation was found in the phase analysis of the studied materials based on SEM, XRD, X-ray microanalysis, and BCR sequential extraction. The BCR analysis revealed the occurrence of major metals in four different fractions: acid-soluble, reducible, oxidizable, and residual. Pb was mainly present in the acid-soluble fraction, while Fe, Cu, and Zn were present in the residual fraction.

The Drentsche Aa catchment in The Netherlands, which has nearly untouched natural river valleys, is a designated Natura 2000 area. Agriculture is practiced on the adjacent higher-lying ground. A set of measures was drafted to achieve climate-proof solutions in the short term by reducing the effects of a drier climate on nature and agriculture. These measures must have no adverse effects. In order to check this, the Hunze and Aa’s Water Board investigated the feasibility of using groundwater for sprinkler irrigation in parts of the catchment. In the study, the SIMulation of GROundwater and surface water levels (SIMGRO) hydrological model was used in order to model future scenarios with different water level strategies and climate scenarios. The modelling examined various measures in the nature and agricultural areas to optimise the hydrological situation for both land use functions. In addition, the effect on the nature areas of abstracting groundwater for irrigation was determined for buffer zones of different widths. The findings have indicated the policy direction to be taken by both the water board and the province, as well as offer them opportunities to deal with the requests for withdrawals in the near future by the means of future-proof general rules.

Thermal spraying methods are commonly used to regenerate damaged surface or change materials surface properties. One of the newest methods is cold spraying, where coating is deposited of material in the solid state. Therefore shape and size of the powder particles are very important parameters. The article presents the influence of copper powder morphology on mechanical properties of the coatings (adhesion, hardness, Young’s modulus) deposited with the Low Pressure Cold Spraying method on the AA1350 aluminium alloy substrate. The coatings were deposited using two commercially available copper powders with spherical and dendritic morphology and granulation of –40+10 µm. The bond strength of coatings was determined with the pull off method, the hardness with the Vickers method at load of 2.94 N, while the Young’s modulus through measurement of nanoindentation. Microstructure of the coatings was analysed using the light and scanning electron microscopy (SEM). Shape of the powder influences mechanical properties of the coating significantly. The coatings deposited with dendritic powder had low mechanical properties, hardness of the 81 HV0.3 order and adhesion of about 4 MPa. However changing powder morphology to spherical increased hardness of the coating to 180 HV0.3 and adhesion to 38.5 MPa.

The influence of friction stir welding (FSW) in automotive applications is significantly high in recent days as it can boast beneficial factors such as less distortion, minimized residual stresses and enhanced mechanical properties. Since there is no emission of harmful gases, it is regarded as a green technology, which has an energy efficient clean environmental solid-state welding process. In this research work, the FSW technique is employed to weld the AA8011–AZ31B alloy. In addition, the L16 orthogonal array is employed to conduct the experiments. The influences of parameters on the factors such as microstructure, hardness and tensile strength are determined. Microstructure images have shown tunnel formation at low rotational speed and vortex occurrence at high rotational speed. To attain high quality welding, the process parameters are optimized by using a hybrid method called an artificial neural network based genetic algorithm (ANN-GA). The confirmation tests are carried out under optimal welding conditions. The results obtained are highly reliable, which exhibits the optimal features of the hybrid method.

The presented results describe the effect of severe plastic deformation on the structure and mechanical properties of AA5083 and AA5754 alloys. Both materials were subjected to single hydrostatic extrusion (HE) and cumulative hydrostatic extrusion in the case of AA5083 and a combination of plastic deformation by equal-channel angular pressing (ECAP) with the next HE for AA5754. After the deformation, both alloys featured a homogeneous and finely divided microstructure with average grain size deq = 140 nm and 125 nm for AA5083 and AA5754, respectively. The selection of plastic forming parameters enabled a significant increase in the UTS tensile strength and YS yield stress in both alloys – UTS =  510 MPa and YS = 500 MPa for alloy AA5083 after cumulative HE, and 450 MPa and 440 MPa for alloy AA5754 after the combination of ECAP and HE, respectively. It has been shown on the example of AA5083 alloy that after the deformation the threads of the fasteners made of this material are more accurate and workable at lower cutting speeds, which saves the cutting tools. The resultant properties of AA5083 and AA5754 alloys match the minimum requirements for the strongest Al-Zn alloys of the 7xxx series, which, however, due to the considerably lower corrosion resistance, can be replaced in many responsible structures by the AA5xxx series Al-Mg alloys presented in this paper.

In this investigation, high specific strength precipitation hardenable alloy AA7068-T6 was joined using friction stir welding. Experiments were carried out using the three factor-three level central composite face-centered design of response surface methodology. Regression models were developed to assess the influence of tool rotational speed, welding speed, and axial force on ultimate tensile strength and elongation of the fabricated joints. The validity of the developed models was tested using the analysis of variance (ANOVA), actual and adjusted values of the regression coefficients, and experimental trials. The analysis of the developed models together with microstructural studies of typical cases showed that the tool rotational speed and welding speed have a significant interaction effect on the tensile strength and elongation of the joints. However, the axial force has a relatively low interaction effect with tool rotational speed and welding speed on the strength and elongation of the joints. The process variables were optimized using the desirability function analysis. The optimized values of joint tensile strength and elongation – 516 MPa and 21.57%, respectively were obtained at a tool rotational speed of 1218 rpm, welding speed of 47 mm/ min, and an axial force of 5.3 kN.