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Cubic garnet Li 6.24 La 3 Zr 2 Al 0.24 O 11.98 (LLZO) is a candidate material for use as an electrolyte in Li–Air and Li–S batteries. The use of LLZO in practical devices will require LLZO to have good mechanical integrity in terms of scratch resistance (hardness) and an adequate stiffness (elastic modulus). In this paper, the powders were fabricated by powder processing of cast ingots. All specimens were then densified via hot pressing. The room temperature elastic moduli (Young’s modulus, shear modulus, bulk modulus, and Poisson’s ratio) and hardness were measured by resonant ultrasound spectroscopy, and Vickers indentation, respectively. For volume fraction porosity, P , the Young’s modulus was 149.8 ± 0.4 GPa ( P  = 0.03) and 132.6 ± 0.2 GPa ( P  = 0.06). The mean Vickers hardness was 6.3 ± 0.3 GPa for P  = 0.03 and 5.2 ± 0.4 for P  = 0.06.

It is becoming an urgent need to synthesize novel alloy possessing both corrosion resistance and sufficient plasticity to meet various functionality requirements in severe corrosion working environment. This study introduced a new Fe-Cr-Ni-based alloy with gradient composition which was fabricated by additive manufacturing with pre-mixed elemental powder. A thin wall sample was fabricated from bottom to top layer by layer following four composition designs (Fe-16Cr-8Ni, Fe-14Cr-16Ni, Fe-12Cr-23Ni, and Fe-9Cr-28Ni) to achieve the transition from ferritic phase to austenite phase. The elemental powders’ shape and size distribution were characterized and analyzed first. The mixing enthalpy for the three elements was studied since it can impact on the deposits homogeneity. Microscopic metallography of the sample was acquired to analyze the microstructure. Then, the phase identification was investigated by X-ray diffraction (XRD). Energy dispersive spectroscopy (EDS) analysis examined the composition in the sample. The results indicate that the microstructure of regions with 8 and 16% of Ni was mainly the lathy and skeletal morphologies, while standard austenite morphology, cells, and dendrites were observed in the regions with 23 and 28% Ni. Then, Vickers hardness test was used to observe the gradually changing hardness profile. In addition, a thermodynamic modeling was employed to predict the Fe-Cr-Ni alloy’s formed phase at room temperature, then compared with the XRD pattern. The experimental-computational approach described herein for characterizing the new Fe-Cr-Ni alloy can be used to improve the understanding and design of other new alloys.

In the current study, the feasibility of fabricating copper–nickel alloys by using laser metal deposition and blended powder feedstocks was investigated through material characterization. Material fabricated from the blended powder mixtures containing elemental nickel was seen to possess large amounts of gas and shrinkage porosity. Due to this porosity, elemental nickel powder was deemed to be an unviable modular feedstock. Instead, Delero-22, a high nickel content alloy, was identified as a viable substitute for elemental nickel. The silicon and boron alloy additions in Delero-22 alloy were identified to be crucial in overcoming the porosity prevalent when using elemental nickel. Counterparts to commercially available copper–nickel alloys were then fabricated using blended elemental copper and Delero-22 alloy powders. Thus, fabricated alloys were characterized using X-ray diffraction, scanning electron microscopy, Vickers hardness testing, energy-dispersive X-ray spectroscopy, and mini-tensile testing. Analyses revealed that the deposited material was formed with homogenous microstructure and the resultant compositions were close to as-blended feedstocks. The results from tensile testing showed an increase in strength caused by solid solution strengthening upon addition of copper to nickel. The addition of copper also increased the ductility of the material. Analysis of the fracture surface revealed changes in the fracture mechanism from transgranular to ductile with an increase in copper content. Variation in scan speed during laser metal deposition resulted in a change in average secondary dendrite arm spacing and variability in tensile performance.

This is the second of two papers by the authors associated with materials characterisation methods based on hardness testing. It is important to have knowledge of the tip geometry of the indenter employed in the hardness test as this affects the correctness of the value of contact area parameter used to determine the mechanical properties. In this paper, outcomes of a study concerned with the tip geometry of the Vickers microindenter are presented. Results from experiment are compared with results from published works and the most current accepted analytical models. A new non-contact methodology based on a residual imprint imaging process is developed and further compared with other methods using experimental and numerical analyses over a wide range of material properties. For confirmation, an assessment was undertaken using numerical dimensional analysis which permitted a large range of materials to be explored. It is shown that the proposed method is more accurate compared with other methods regardless of the mechanical properties of the material. The outcomes demonstrate that measuring contact area with the new method enhanced the overall relative error in the resulting mechanical properties including hardness and Young’s modulus of elasticity. It is also shown that the value of the contact area using actual indenter geometry obtained from experimental load-displacement analysis or FEM numerical analysis is more accurate than the value obtained from the assumption of perfect indenter geometry and hence can be used for materials with low strain hardening property.

Double-sided laser beam welding of skin-stringer joints is a proven method for many industrial applications such as in aircraft assemblies where riveted differential joints are being replaced with welded integral structures. In the present study, dissimilar aluminum alloys of AA2024-0 and AA7075-T6 were laser welded on both sides in a T-joint configuration using a low-power Yb-fiber laser with the addition of a BA4047 filler wire. The optimized parameters were determined by developing a Mamdani fuzzy smart model. The influence of BA4047 filler wires on weld morphology was investigated using optical microscopy (OM) and scanning electron microscope (SEM). The cross-section of the joints revealed that the fusion zone (FZ) and heat affected zones (HAZ) are wider when filler wire was added as compared to those without it. This result shows that the low-power fiber laser has sufficient energy to melt the tip of the filler wire and subsequently the base materials, forming a liquid bridge to facilitate the smooth flow of molten metal between the stringer and the skin. No obvious voids were observed in the cross-sections of the joint interface. The strengths of joints were evaluated using a pull test, and hardness values were measured at the base metal (BM), FZ, and HAZ using the Vickers hardness test. At lower welding speeds with constant low-laser power, it was shown that the addition of the aluminum-silicon base alloy has increased the overall hardness and welding strengths of the samples.

Three-dimensional (3D) printing is increasingly being utilized in the dental field. After fabricating a prosthesis using a 3D printed resin, a post-curing process is required to improve its mechanical properties, but there has been insufficient research on the optimal post-curing conditions. We used various 3D printed crown and bridge materials in this study, and evaluated the changes in their properties according to post-curing time by evaluating the flexural strength, Weibull modulus, Vickers hardness, color change, degree of conversion, and biocompatibility. The obtained results confirmed that the strength of the 3D printed resin increased when it was post-cured for 60–90 min. The Vickers hardness, the degree of conversion, and biocompatibility of the 3D printed resins increased significantly around the beginning of the post-curing time, and then increased more gradually as the post-curing time increased further. It was observed that the color tone also changed as the post-curing time increased, with some groups showing a ΔE00 value of ≥ 2.25, which can be recognized clinically. This study has confirmed that, after the printing process of a 3D printed resin was completed, a sufficient post-curing time of at least 60 min is required to improve the overall clinical performance of the produced material.

We report on responses of hydrated and dehydrated cortical bone tissues to mechanical loading applied by a Vickers indenter. The Vickers indentations were imaged in two- and three-dimensions (2D and 3D) using confocal laser scanning microscopy (CLSM) to understand mechanical behavior of bone tissues. Serial optical sections of indentation patterns of dry and wet bones were collected using CLSM. The indention surface structures were mapped using topographical CLSM imaging. The observation of CLSM shows the fundamental indentation responses for both the hydrated and dehydrated bone tissues were plastic deformation. No visible fracture was observed in the Vickers indentation patterns in the wet bone tissue, while non-propagating lamellar microcracks occurred in the dry bone tissue. This indicates that drying resulted in increased brittleness of the bone tissue. The Vickers hardness values of dry bone tissue were significantly higher than those of wet bone tissue at any applied loads (analysis of variation, ANOVA, p  < 0.05). The resolution limits of confocal microscopy were also discussed for bone tissue scanning.

The paper examines a technique for producing metal-cutting ceramics from the plasmadynamic synthesis product using the spark plasma sintering technology. It studies the dependence of physico-mechanical properties of ceramics on the mixture parameters. Increase in bulk density and effect produced by this increase are well observed when comparing the sintering process curves. Movable die displacement for non-activated powder is 3.5 mm, while powder activation allowed reaching the 1.75 mm displacement, other conditions being equal. Hardness of produced materials measured by Vickers method was 21 GPa for non-activated powder and 17 GPa for activated powder at relative densities of sintered ceramic workpieces in relation to osbornite monocrystal of 92% and 93.5% respectively. Significant increase in density of the sintered body is ensured mainly by elimination of the raw material agglomeration.

Organic single crystals of 2-amino-5-chlorobenzophenone (2A5CB) were grown by Microtube Czochralski method using Microtube as a seed. The grown crystals were characterized by single crystal and powder X-ray diffraction. The functional groups of the grown crystal were found using Fourier transform infrared spectroscopy. The cutoff wavelength of 2A5CB has been identified using UV–vis–NIR studies. Thermogravimetric/differential thermal analysis (TG/DTA) has been carried out to find the thermal behaviour. 2A5CB was found to be thermally stable up to 125 ∘ C. Powder second harmonic generation (SHG) was investigated to explore its nonlinear optical (NLO) properties. The mechanical stability of 2A5CB is studied by using Vickers hardness testing.

Background. Recently, dentists can utilize three-dimensional printing technology in fabricating dental restoration. However, to date, there is a lack of evidence regarding the effect of printing layer thicknesses and postprinting on the mechanical properties of the 3D-printed temporary restorations with the additive manufacturing technique. So, this study evaluated the mechanical properties of a 3D-printed dental resin material with different printing layer thicknesses and postprinting methods. Methods. 210 specimens of a temporary crown material (A2 EVERES TEMPORARY, SISMA, Italy) were 3D-printed with different printing layer thicknesses (25, 50, and 100 μm). Then, specimens were 3D-printed using DLP technology (EVERES ZERO, DLP 3D printer, SISMA, Italy) which received seven different treatment conditions after printing: water storage for 24 h or 1 month, light curing or heat curing for 5 or 15 minutes, and control. Flexural properties were evaluated using a three-point bending test on a universal testing machine (ISO standard 4049). The Vickers hardness test was used to evaluate the microhardness of the material system. The degree of conversion was measured using an FT-IR ATR spectrophotometer. Statistical analysis was performed using two-way analysis of variance (ANOVA) and Tukey’s honestly significant difference (HSD) test (p≤0.05). Results. The 100 μm printing layer thickness had the highest flexural strength among the other thickness groups. As a combined effect printing thickness and postprinting conditions, the 100 μm with the dry storage group has the highest flexural strength among the tested groups (94.60 MPa). Thus, the group with 100 μm thickness that was heat cured for 5 minutes (HC 5 min 100 μm) has the highest VHN value (VHN=17.95). Also, the highest mean DC% was reported by 50 μm layer thickness (42.84%).Conclusions. The thickness of the 100 μm printing layer had the highest flexural strength compared to the 25 μm and 50 μm groups. Also, the postprinting treatment conditions influenced the flexural strength and hardness of the 3D-printed resin material.