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Two strength-age hardening aluminum-lithium alloys: Al-2.3wt%Li and Al-2.2wt%Li-0.1wt%Zr in two different heat treatment conditions: solution state (S) and additionally in aging state (A) were severely plastically deformed by rolling with cyclic movement of rolls (RCMR) method to produce ultrafine – grained structure. Two thermo-mechanical treatments were used: (S+A+RCMR) and (S+RCMR+A+RCMR). To investigate the combined effect of plastic deformation and heat treatment, tensile tests were performed. Microstructural observations were undertaken using scanning transmission electron microscopy (STEM), and scanning transmission electron microscopy (SEM) equipped with electron backscattering diffraction detector (EBSD). Based on the obtained results, it can be deduced that maximum mechanical properties as: yield strength (YS) and ultimate tensile strength (UTS) could be achieved when the microstructure of alloys is in (S+A+RCMR) state. For samples in (S+RCMR+A+RCMR) state, ductility is higher than for (S+A+RCMR) state. The microstructural results shows that the favourable conditions for decreasing grain size of alloys is (S+A+RCMR) state. Additionally, in this state is much greater dislocation density than for (S+RCMR+A+RCMR) state. The microstructure of alloys in (S+RCMR+A+RCMR) state is characterized by grains/subgrains with higher average diameter and with higher misorientation angles compared with (S+A+RCMR) state.

Additive manufacturing (AM) has seen remarkable development in recent years due to relatively high efficiency of the process. Cold spraying (CS) is a particular method of AM, in which titanium and titanium alloy powders are used. CS is a very competitive technology enabling the deposition of coatings, repairing machine parts, and manufacturing new components. For specific applications, the surface of cold-sprayed materials may require further processing. This paper reports an attempt to employ laser surface treatment (LST) of cold-sprayed coatings on an aluminium alloy substrate. The influence of laser beam interaction time on the coatings' properties was analysed. The microstructure was investigated and observed employing scanning electron microscopy (SEM). To evaluate residual stress after CS and LST, the sin 2 ψ technique was used. Investigations were also performed on Vickers hardness, contact angle, and surface roughness. Significant changes in the surface morphology of the coatings and elevated residual stress levels dependent on the laser beam interaction time were observed. Increased Vickers hardness was recorded for titanium alloy Ti6Al4V. LST also led to increased surface hydrophilicity of the modified materials Ti and Ti6Al4V.

The poly(lactic acid) (PLA) biodegradable polymer, as well as natural, siliceous reinforcement in the form of diatomaceous earth, fit perfectly into the circular economy trend. In this study, various kinds of commercial PLA have been reinforced with diatomaceous earth (DE) to prepare biodegradable composites via the extrusion process. The structure of the manufactured composites as well as adhesion between the matrix and the filler were investigated using scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) analyses were carried out to determine crystallinity of PLA matrix as function of DE additions. Additionally, the effect of the ceramic-based reinforcement on the mechanical properties (Young's modulus, elongation to failure, ultimate tensile strength) of PLA has been investigated. The results are discussed in terms of possible applications of PLA + DE composites.

Novel metal matrix composites (MMCs) have been fabricated with Ti6Al4V matrix and a biogenic ceramic filler in the form of diatomaceous earth (DE). Mixtures of DE and Ti6Al4V powders were consolidated by the spark plasma sintering (SPS) method. Microstructure of the consolidated samples has been investigated with microscopic techniques and XRD. Thermomechanical characteristics have been obtained using small-sample techniques. The results obtained indicate that the fabricated composites show outstanding mechanical and thermal properties due to synergic effects between the filler and the matrix (beyond the rule of mixtures)., (© 2022. The Author(s).)

Designers' efforts to use the lightest possible materials with very good mechanical properties mean that in recent years magnesium alloys have been increasingly used. It is well-known that the use of various plastic working processes allows achieving even better strength properties of the material, often without significant loss of plastic properties in relation to the properties of products obtained in the casting process. The article presents the results of research on microstructural changes and mechanical properties of the alloy AZ91 (MgAl9Zn1) occurring in samples subjected to conventional plastic deformation and the KOBO method. The obtained results were compared to the properties of reference samples, i.e., cast samples. The article presents the advantage of using the low-temperature KOBO method compared to the high-temperature deformation in a conventional manner. Moreover, it has been shown that the use of KOBO extrusion allows the alloy AZ91 (MgAl9Zn1) to obtain superplasticity properties with an elongation of up to 577% compared to the cast reference sample, which is generally classified as difficult for plastic deformation.

In this research, the cold spray process as an additive manufacturing method was applied to deposit thick titanium coatings onto 7075 aluminium alloy. An analysis of changes in the microstructure and mechanical properties of the coatings depending on the standoff distance was carried out to obtain the maximum deposition efficiency. The process parameters were selected in such a way as to ensure the spraying of irregular titanium powder at the highest velocity and temperature and changing the standoff distance from 20 to 100 mm. Experimental studies demonstrated that the standoff distance had a significant effect on the microstructure of the coatings and their adhesion. Moreover, its rise significantly increased the deposition efficiency. The standoff distance also significantly affected the coating microstructure and their adhesion to the substrate, but did not cause any changes in their phase composition. The standoff distance also influenced the coating porosity, which first decreased to a minimum level of 0.2% and then increased significantly to 9.8%. At the same time, the hardness of the coatings increased by 30%. Numerical simulations confirmed the results of the tests.

Background: The one of the most recent imaging technology is X-ray microtomography which allows non-invasive three-dimensional visualisation of structures. It also offers the opportunity to conduct a comprehensive quantitative analysis of the tested objects such as measuring the shares of the various phases, determining the material density and distribution of the size of pores and particles. The aim of the paper was to present an overview on the applicability and relevance of X-ray microtomography in the study of mineralised tissues of the teeth., Materials and Methods: The article is based on the most recent and significant literature and own observations., Results: The use of X-ray microtomography in dentistry has recently increased and includes, inter alia, the assessment of the density of minerals in enamel and dentin, the detection of demineralisation in an artificially and a naturally induced caries, the automatic measurement of the depth of cavities in dentin, the measurement of the amount of removed dentin in preparation of carious lesions by various methods, the assessment of microleakage around fillings and fissure sealants, cortical bone density measurement, evaluation of root canal morphology, comparison of the accuracy of root canal working and filling by various methods., Conclusions: X-ray microtomography offers within the analysis of mineralised tissues - complex structures of bone, teeth and biomedical materials, turn out to be indispensable since it opens new opportunities for cognitive and implementation research.

The use of adhesive bonding systems and composites in prosthetic dentistry brought improved and more aesthetic prosthetic restorations. The adhesive bonding of porcelain veneers is based on the micromechanical and chemical bond between tooth surface, cement layer and ceramic material. The aim of the study was to measure the thickness of the material layer formed during cementing of a ceramic restoration, and - in the second part of the study - to test tension of these cements. The materials investigated comprised dual-curing materials: Variolink II, KoNroot Cem, KoNroot Cem Viscous and Panavia F 2.0, as well as a light-curing composite: Variolink Veneer. The thickness was measured with the use of ZIP Lite 250 optical gauging apparatus. SEM microscope - Hitachi Tabletop Microscope TM-100 - was used to analyse the characteristics of an adhesive bond and filler particle size of particular materials. Tension tests of the cements under study were carried out on the MTS Q Test 10 static electrodynamic apparatus. The tests showed that KoNroot Cem exhibited the best mechanical properties of bonding to enamel and dentin among the materials tested. Variolink II base light-curing cement formed the thinnest layer. All the materials tested formed the layer not exceeding 1/3 of ceramic restoration thickness.