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A hydrostatic extrusion (HE) process was applied to commercial pure polycrystalline aluminium (99.9%) and two aluminium single crystals ⟨111⟩ and ⟨110⟩. On comparison, the results obtained from single crystals and polycrystalline aggregates are unique. Microstructure and crystallographic texture investigations were performed by transmission electron microscopy, electron backscatter diffraction and X-ray diffraction (XRD). Significant differences in grain refinement and texture formation were noticed depending on the starting orientation. The deformed single crystal with ⟨ 110 ⟩ starting orientation features an average grain size value of 150% higher than the second investigated single crystal (0.5 μm for the ⟨111⟩ single crystal and 1.3 μm for the second crystal). In turn, the average grain size obtained for polycrystalline aluminium is 0.9 μ m . The deformation process causes a difference in the grain sizes, while a fraction of the high angle grain boundaries have a comparable volume percentage in all the deformed microstructures—reached about 35%. The qualitative and quantitative XRD texture results proved that the HE process leads to the formation of a characteristic fibrous texture. [ABSTRACT FROM AUTHOR]

The aim of the work was to produce laminated structures consisting of Ti–6Al–4V alloy and AA2519 plates and to investigate their microstructure and mechanical properties with an emphasis on the role of an additional AA1050 interlayer. Explosive welding was selected as a joining technology. The microstructure and chemical composition of the explosively joined samples were investigated. Mechanical properties were evaluated in the tensile testing and by microhardness analysis. The results demonstrated that explosive welding is an effective way to produce Ti/Al laminates. Both Ti6Al4V/AA2519 and Ti6Al4V/AA1050/AA2519 laminated plates exhibit good quality of bonding without voids and major delamination. The explosive welding produced metallurgical bonding with a nanostructured zone consisting of Al 3 Ti and Al 2 Ti phases. This zone is thicker in the joint with additional AA1050 interlayer when compared to direct AA2519/Ti6Al4V bonding. In the latter, SEM and STEM analysis reviled the presence of net-like structure in the collision zone. Advanced EDX analysis shows the enrichment of grain boundaries in copper. The formation of this structure is widely discussed. In addition, the explosive welding introduces large plastic deformation which induces the process of grain refinement in aluminium plates. Tensile testing confirms that joining section is not the weakest element of the cladded plates. [ABSTRACT FROM AUTHOR]

The influence of different types of precipitation on the corrosion behavior was investigated in three aluminum-siliconmagnesium alloys. The microstructures of the alloys were studied through optical (OM) and scanning electron microscopy (SEM). The structures consisted of an α-Al solid solution matrix, Si eutectic crystals, secondary phases AlFeSi and AlMgFeSi (Chinese script), as well as Mg2Si. The corrosion behavior was examined with the use of a potentiodynamic polarization test followed by a SEM surface analysis. The results indicate that all the analyzed samples were in the passive state and AlSi10Mg was less reactive in the corrosive environment. [ABSTRACT FROM AUTHOR]

Abstract: The nanostructure and mechanical properties of ferritic-austenitic duplex stainless steel subjected to hydrostatic extrusion were examined. The refinement of the structure in the initial state and in the two deformation states (ε=1.4 and ε=3.8) was observed in an optical microscope (OM) and a transmission electron microscope (TEM). The results indicate that the structure evolved from microcrystalline with a grain size of about 4μm to nanocrystalline with a grain size of about 150nm in ferrite and 70nm in austenite. The material was characterized mechanically by tensile tests performed in the two deformation states. The ultimate strength appeared to increase significantly compared to that in the initial deformation stages, which can be attributed to the grain refinement and plastic deformation. The heterogeneity observed in microregions results from the dual-phase structure of the steel. The results indicate that hydrostatic extrusion is a highly potential technology suitable for improving the properties of duplex steels. [Copyright &y& Elsevier]

Microstructure and creep properties of cast Mg-Al-Ca-Sr alloys have been investigated. The microstructure was characterized using light microscopy, scanning and transmission electron microscopy. Phase identification was made by EBSD technique and by SAED analysis. The measurement of volume fraction of intermetallic phases was performed using quantitative metallography. Creep tests were performed at 180°C and at applied stress between 45 and 90 MPa. Microstructure of tested alloys composed of α-Mg grains and intermetallic compounds in the interdendritic regions. It was found that the addition of calcium and strontium improves creep resistance at 180°C. [ABSTRACT FROM AUTHOR]

Abstract: The results obtained in the present study demonstrate the effect of various modes of severe plastic deformation (SPD) on the thermal stability of model Al–Li alloys (Li atoms in the solid solution). Two aluminium–lithium alloys (Al–0.7wt.% Li and Al–1.6wt.% Li) were processed by hydrostatic extrusion (HE) and equal channel angular extrusion (ECAE). The thermal stability was estimated using differential scanning calorimetry (DSC). The DSC analysis confirms that the recovery and grain growth occur systematically at lower temperatures and at reduced activation energies in the alloy with the lower lithium content. The effects of microstructural changes taking place in the deformed aluminium alloys during annealing were evaluated by Vickers micro-hardness measurements. In all the specimens only a weak softening occurs at the lowest (373K) annealing temperature. In the specimens annealed at 556K, an intensive hardness decrease was observed after the shortest time of annealing (for example: annealing the HE-treated Al–1.6 Li alloy for 30s leads to a decrease of HV0.2 by about 8%). The results show that the thermal stability of the alloys increases with increasing solute content. [Copyright &y& Elsevier]

Microstructure and texture of the CuCr0.6 alloy processed by rolling with cyclic movement of rolls (RCMR) at room temperature were investigated. The RCMR processing was applied for the samples in different initial conditions in the solid solution followed by quenching into iced water at 1000oC for 3 h and in aging treatment conditions performed at 500oC for 2 h and at 700oC for 24 h. Application of the solution and aging processes prior to RCMR deformation results in the partial dissolution of Cr particles into the Cu matrix and precipitation of the second phase particles. RCMR processing with value of the total effective strain (eft) of 5 was introduced to the material. It was found that the RCMR method is effective in texture weakening. The obtained results revealed that there is a large similarity in texture orientations after RCMR processing independently of heat treatment conditions. Cyclic character of deformation leads to an incomplete transition of LAB to HAB. [ABSTRACT FROM AUTHOR]

The paper presents the results of investigations of the microstructures and properties of the aluminium coatings deposited by vacuum evaporation and magnetron sputtering. These coatings generally have a very refined microstructure with elongated nano-grains. However, the surface topography of the aluminium coating deposited by vacuum evaporation is more developed, its microstructure is less homogeneous and more porous. The residual tensile stresses in the aluminium coating deposited by magnetron sputtering are close to 130 MPa, and the texture is relatively pronounced. Vacuum evaporation does not induce residual stresses in the coatings and the texture is very weak. The results obtained indicate that the aluminium coatings produced by magnetron sputtering are more suitable for the diffusive Ti-Al intermetallic layers. [ABSTRACT FROM AUTHOR]

AISI 316L steel was subjected to nitrocarburizing under glow discharge conditions, which was followed by Dlc (diamondlike carbon) coatings deposition using the same device. The coatings were applied under conditions of direct current and pulsed glow discharge. in order to determine the influence of the produced nitrocarbon austenite layer and the type of discharge on the microstructure and mechanical properties of the coatings, the following features were analysed: surface roughness, coating thickness, structure, chemical composition, adhesion and resistance to frictional wear. For comparison purposes, Dlc coatings were also deposited on steel without a nitrocarburised layer. The obtained results indicate a significant influence of the type of glow discharge on the roughness, hardness, nitrogen content and of the nitrocarburised layer on the resistance to wear by friction and adhesion of the produced coatings. [ABSTRACT FROM AUTHOR]

This article describes the manufacturing of silicon carbide composites with the addition of quasi-two-dimensional titanium carbide Ti3C2, known as MXene. The composites were obtained by the powder metallurgy technique, consolidated with the use of the Spark Plasma Sintering method at 1900 °C and dwelled for 30 min. The influence of the Ti3C2 MXene addition on the microstructure and mechanical properties of the composites was investigated. The structure of the MXene phase after the sintering process was also analyzed. The results showed a significant increase (almost 50%) of fracture toughness for composites with the addition of 0.2 wt% Ti3C2 MXene. In turn, the highest hardness, 23.2 GPa, was noted for the composite with the addition of the 1.5 wt% Ti3C2 MXene phase. This was an increase of over 10% in comparison to the reference sample. The analysis of chemical composition and observations using a transmission electron microscope showed that the Ti3C2 MXene phase oxidizes during sintering, resulting in the formation of crystalline, highly defected, disordered graphite structures. The presence of these structures in the microstructure, similarly to graphene, significantly affects the hardness and fracture toughness of silicon carbide. [ABSTRACT FROM AUTHOR]

Corrosion tests were carried out to study the corrosive behaviour of medium carbon steels with a ferrite-pearlite microstructure during exposure to a synthetic flowback facturing fluid saturated with carbon dioxide. Metallographic investigations, screening tests, surface morphology investigations and identification of surface products were used for this purpose. The results obtained indicate that the corrosion of N80-1 carbon steel was significantly lower than that of K55 carbon steel. The layer of corrosion products consisted of an outer layer of carbonates and an inner layer with cementite lamellas. Higher grain refinement of N80-1 steel compared to that of K55 steel caused the formation of a denser, more homogenous layer of corrosion products, which significantly reduced the corrosion of the base material. [ABSTRACT FROM AUTHOR]

The microstructure of Mo was significantly refined by high pressure torsion to verify its irradiation tolerance in comparison with its micrograined counterpart. After deformation microhardness increased from 231 Hv0.2 for a microgarined sample to 542 and 558 Hv0.2, respectively after one and five rotations. Concurrently, the grain refinement was observed, as the grain size decreased with the increase of the deformation degree down to 480 and 110 nm, respectively for one and five rotations. Subsequently, deformed Mo and a micrograined one were irradiated by He ions to the dose of 8 × 1016/cm 2 to verify their potential application as fusion mirrors. Irradiations were followed by reflectivity measurements in the 300–2400 nm range with a dual beam spectrometer. The measurements revealed that the applied dose causes a decrease in total reflectivity of the micrograined sample, whereas the total reflectivity of deformed samples decreases by additional 2.5%. Nanohardness measurements, detailed microscopy observations using focused ion beam and scanning transmission electron microscope as well as positron annihilation spectroscopy investigations were performed to elucidate changes in the microstructure and understand the different mechanisms of bubble creation after irradiation in micrograined and high pressure torsion processed samples. • Micrograined and HPT-processed Mo were irradiated with He ions. • HPT of Mo leads to a less significant increase in nanohardness after irradiation. • HPT of Mo contributes to higher density of nanocracks after irradiation. • Positron annihilation spectroscopy was used to characterize vacancies. [ABSTRACT FROM AUTHOR]

In this work the results of basic material studies of the zinc and copper oxides as components of heterojunction solar cells were shown. Basing on the optical constants the light absorption properties and range of required thicknesses of copper oxides absorber were indicated. Depletion Region Approximation method was used for analytical studies of heterojunction properties: built in voltage, junction width and band structure. The maximal attainable open circuit voltages and short circuit current led to the estimation of efficiency limits of ZnO/Cu 2 O and ZnO/CuO solar cells. Experimental part included material studies of low temperature copper sheets oxidation and atomic layer deposition of zinc oxide. Controlling the low temperature oxidation condition allowed for homogeneously grown oxide layer of controlled thickness, absorption properties and surface roughness. Unlabelled Image • Main principles for designing solar cells from inexpensive, earth-abundant ZnO/Cu x O. • Absorption ability and conditions of built-in voltage formation. • 9 and 24% the assessed efficiency limits for ZnO/Cu 2 O and CuO. • Thermal oxidation and ALD proved to be suitable for practical implementation. • Temperature of materials processing shown as the key factor. [ABSTRACT FROM AUTHOR]