Vickers Hardness Measurements Research Articles

Ion-exchange enhancement of borosilicate glass vials for pharmaceutical packaging

Pharmaceutical containers for parenteral use, including vials, ampoules, prefilled syringes, and cartridges, are traditionally made of glass. However, the most commonly used type, borosilicate glass, is susceptible to issues such as breakage, corrosion, and delamination, which can jeopardize the safety and efficacy of the enclosed drugs. To address these concerns without compromising the visual or qualitative aspects of borosilicate medical glass vials, this study aimed at the enhancement of their mechanical, chemical, and corrosion resistance. A single ion exchange treatment (IET) in a salt bath of molten KNO3 at temperatures of 400, 450, and 500 °C for 2, 12, and 24 h was applied. The effects of the ion exchange process performed under different conditions were assessed by measuring Vickers hardness, crushing load, and chemical durability. The mechanical load required to crush full-body vials after the ion exchange process at 500 °C for 2, 12, and 24 h showed an increase in the applied force values (1650 ± 80, 2340 ± 80, and 2325 ± 40 N) compared to untreated vials (1157 ± 20 N).No radial cracks were observed on the surface of treated glass vials after indentation, indicating the presence of compressive stresses that prevented the initiation and propagation of cracks. The EDS analysis confirmed an increase in potassium concentration and a decrease in sodium content near the surface of samples modified by ion exchange treatment. The treated samples showed appropriate chemical stability in different acidic, basic, and neutral solutions. Conspicuous changes are noticed in the Raman spectra after IET, specifically in the Qn species region. The results indicate the potential of the ion exchange treatment in enhancing the properties of borosilicate glass vials by relatively simple and easily scalable techniques.

Enhanced properties of hard metal WC-Ni processed from nanostructured powders

In this study, we investigated the effects of nanostructured composite powders (WC-Ni), nickel binder content, and sintering techniques on the morphology and mechanical properties of tungsten carbide. An alternative low-temperature gas-solid reaction route with a short reaction time was employed to produce nanostructured composite powders with 5 and 15 wt% Ni. The powders were consolidated using spark plasma sintering (SPS) and conventional vacuum furnace sintering at temperatures of 1350 °C and 1450 °C. The composite powders were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and particle size measurements. The expansion/contraction of the compacted nanocomposite powders was studied through dilatometric analysis. The composite powders exhibited a uniform distribution of Ni, in both compositions. For the WC-5 wt% Ni nanocomposite powders, the average crystallite sizes for WC and Ni were 41.6 nm and 46.2 nm, respectively. While, for the WC-15 wt% Ni nanocomposite, the crystallite sizes for WC and Ni were 45.6 and 38.4 nm. The sintered composites were evaluated through XRD, SEM, measurements of density and Vickers hardness. The enhanced sinterability of the nanostructured powders enabled their consolidation into (WC-Ni) hard metal with densities approaching the theoretical relative density of 96.07 %, even with low binder content (5 wt% Ni). This is attributed to the uniform distribution of Ni and an extensive Ni-WC interface present prior to sintering. The SPS process at 1350 °C produced sintered bodies (WC-5 wt% Ni and WC-15 wt% Ni) with higher Vickers hardness (2322 HV and 1512 HV, respectively) and superior microstructural quality compared to samples produced by conventional vacuum furnace techniques. These results demonstrated that the mechanical properties of the system WC-Ni processed by SPS are superior to those obtained by vacuum furnace. Therefore, WC-Ni hard metals processed by this approach is a promising alternative to conventional hard metals (WC-Co) for a wide range of applications.

Microstructure evolution and enhanced mechanical performance of multilayer MXene-reinforced silver matrix composites

In this study, multilayer MXenes were first incorporated into an Ag matrix through a hetero-agglomeration process followed by spark plasma sintering (SPS), with the microstructural evolution of MXenes during composite fabrication characterized using transmission electron microscopy. The partial decomposition of MXene and transformation into rutile-TiO2 nanoparticles occurred during SPS, facilitating the generation of submicron Ag grains through effective pinning. As revealed by the Vickers hardness measurements and tensile tests, the addition of 3 vol% MXene increased the hardness and yield strength of the Ag matrix from 57.7 HV and 97.5 MPa to 116.0 HV and 129.1 MPa, representing increases of 101 % and 32 %, respectively. Quantitative calculations suggested that the improved mechanical properties of the MXene/Ag composites were primarily due to grain refinement strengthening. Meanwhile, the electrical and thermal conductivities of the 3 vol% MXene/Ag composite decreased by 9 % and 11 %, respectively. However, the ultimate tensile strength and ductility of the composites were lower than those of pure Ag, attributed to the weak MXene-Ag interfacial bonding and fracture surface observations, as well as the presence of accordion-like structures in MXene. Compared with conventional Ag matrix composites, MXene/Ag composites demonstrate a superior balance of mechanical and physical properties, making them highly suitable for applications in electrical devices. This work enhances our understanding of the interface phenomena between MXenes and metals, providing new insights for designing novel Ag matrix composites for use in conductive devices.

Enhancing ductility and post-aging strength of tailor welded blanks through pre-aging friction stir welding

Achieving superior ductility, microstructure, and strength simultaneously in tailor-welded blanks remains challenging. To address this, pre-aging blanks before friction stir welding was proposed. Systematic studies were conducted on the microstructure, ductility, and post-aging strength of pre-aged 2219 aluminium alloy after friction stir welding. Uniaxial tensile tests evaluated the ductility of tailor-welded blanks at room and cryogenic temperatures, along with their mechanical properties after artificial aging. Microstructural characterization and Vickers hardness measurements elucidated the strengthening mechanisms between the welded region and base material. No abnormal grain growth was observed in the welded region post pre-aging welding; instead, a finer grain structure prevailed. Ductility of the tailor-welded blanks initially increased and then decreased with increasing rotational speed. Excellent elongations, 27.8% at room temperature and 32.4% at cryogenic temperatures, were obtained at a rotational speed of 1300 rpm, reaching 91.5% of the base material. This attributed to the finer grain boundary strengthening in the welded regions. After artificial aging, a joint efficiency of 93.5% was achieved, owing to effective compensation of the reduction in precipitation strengthening caused by the welded heat input through finer grain strengthening. This approach represents a novel method for preparing ultrawide blanks for forming integral large-sized aluminum alloy components.

Restoration of exceptional mechanical properties of Al–Cu–Li (AA 2198) alloy post-friction stir processing by recovery of T1 precipitates through controlled temper conditions

Friction stir processing (FSP) is considered to be an effective technique to improve the mechanical properties of metallic materials through grain refinement. However, the fine-grained Al–Cu–Li (AA2198) alloy exhibits a drastic reduction in strength post-FSP as compared to its peak aged temper condition due to the dissolution of its primary strengthening phase, T1 (Al2CuLi) during processing. The present study is aimed at recovering T1 precipitates, thereby restoring the alloy strength. The evolution of microstructure in both the base alloy and FSP alloy subjected to different temper conditions was examined by detailed electron microscopy and was analyzed through a differential scanning calorimetry study. The mechanical properties of the alloy were evaluated by Vickers hardness measurements and tensile testing at room temperature. Experimental findings reveal that the direct aging treatment is ineffective in recovering T1 in FSP alloy due to the delayed precipitation kinetics. However, prior cold working led to the recovery of substantial amounts of T1 during further aging of the FSP alloy. The variation in hardness and tensile properties were in alignment with the precipitation states, and the exceptional mechanical properties were restored in the FSP alloy with the recovery of T1 by cold work prior to aging. The strength modeling indicated that the experimental yield strength after T1 recovery is lower than the predicted value, and these are attributed to the incomplete recovery of the T1 due to trapping of the solute in Cu-rich Al based intermetallics. To dissolve the intermetallics solution treatment was performed after FSP, but it led to significant abnormal grain growth (AGG) and is analyzed using Humphrey’s framework.

Additive manufacturing of duplex stainless steel by DED-LB/M and PBF-LB/M – process-material-property relationships

PurposeAdditive manufacturing (AM) of duplex stainless steels (DSS) is still challenging in terms of simultaneously generating structures with high build quality and adequate functional properties. This study aims to investigate comprehensive process-material-property relationships resulting from both laser-directed energy deposition (DED-LB/M) and laser powder bed fusion (PBF-LB/M) of DSS 1.4462 in as-built (AB) and subsequent heat-treated (HT) states.Design/methodology/approachCuboid specimens made of DSS 1.4462 were generated using both AM processes. Porosity and microstructure analyses, magnetic-inductive ferrite and Vickers hardness measurements, tensile and Charpy impacts tests, fracture analysis, critical pitting corrosion temperature measurements and Huey tests were performed on specimens in the AB and HT states.FindingsCorrelations between the microstructural aspects and the resulting functional properties (mechanical properties and corrosion resistance) were demonstrated and compared. The mechanical properties of DED-LB/M specimens in both material conditions fulfilled the alloy specifications of 1.4462. Owing to the low ductility and toughness of PBF-LB/M specimens in the AB state, a post-process heat treatment was required to exceed the minimum alloy specification limits. Furthermore, the homogenization heat treatment significantly improved the corrosion resistance of DED- and PBF-processed 1.4462.Originality/valueThis study fulfills the need to investigate the complex relationships between process characteristics and the resulting material properties of additively manufactured DSS.

Effect of Pre-Deformation on Precipitation in Al–Zn–Mg–Cu Alloy

AbstractIn this work, strengthening effects and evolution of precipitates in a pre-deformed Al–Zn–Mg–Cu alloy during ageing were investigated using Vickers hardness measurements, tensile tests, and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). It was found that all cold rolled conditions had higher mechanical strength than the non-deformed condition for all ageing times and that this effect increases at higher deformation ratios. It was also found that the non-deformed condition has a higher age hardening response than that of the cold rolled conditions. A homogeneous precipitate distribution was observed in the non-deformed condition, while the cold rolled conditions contained non-uniformly distributed precipitates due to the introduced dislocations. This led to larger precipitate sizes and a reduction in the precipitate number densities in the pre-deformed conditions. HAADF-STEM analysis revealed differences in the fraction of different precipitate types between the non-deformed and the cold rolled conditions. η', η2, and disordered η phase were observed in the non-deformed condition, while η', η2 and the newly identified Y phase were observed in the cold rolled conditions. The disordered η phase contained structural units of the η1 phase and was associated with reducing the lattice misfit between this phase and the Al matrix. Formation of the Y phase was related to an accelerated nucleation rate in the regions of high dislocation density. Graphical abstract

Microstructure, Mechanical Properties, and Wear Behavior of Dissimilar Metallic Coatings for Steel Discs of Butterfly Valves

Abstract In the present work, coating materials that can be welded to the EN 1.6220 low-alloy steel disc of a butterfly valve and are also compatible with the seal material, i.e., 17–4 PH steel, are studied. 312 duplex stainless steel, 316 austenitic stainless steel, and Stellite 6 are identified as potential coating materials for the disc based on Cobweb analysis and are welded to the disc using metal active gas (MAG) welding (312 and 316 steel coatings) and powder plasma arc welding (Stellite 6 coating). Microstructural analyses and Vickers hardness measurements of the weld joints are performed. The surface roughness and wear behavior of the coatings are also studied. Nanoscale wear phenomena and consequent phase transformations are studied using molecular dynamics simulations. The results show that 312 and 316 stainless steels are suitable coating materials for the disc.

Investigation and Optimization of The Effect of Anhydrous Borax Mineral on The Vickers Hardness and Indentation Modulus Values of Iron Material

In this study, 5% and 10% by weight of anhydrous borax (AHB) was added to the iron (Fe) matrix material by powder metallurgy method and the effects of the additive ratio on the Vickers hardness (HV), Brinell hardness (HB) and Indentation modulus (EIT) values of the composites (Fe/AHB) were investigated. In the productions carried out using Taguchi experimental design method, AHB additive ratio, and sintering temperature parameters were selected as control parameters that were thought to affect the physical and/or mechanical properties of the Fe/AHB composite materials. The productions were carried out according to the Taguchi L4 orthogonal array, which was created depending on the control parameters and levels. Vickers hardness and indentation modulus measurements of pure iron and Fe/AHB composite materials were performed in accordance with BS EN ISO 14577-1 standard and Brinell hardness measurement was performed in accordance with TS EN ISO 6506-1 standard. According to the signal-to-noise ratio (S/N) analysis performed with the experimental data, it was determined that the 10% AHB additive ratio and 950oC sintering temperature optimized all the investigated properties of the Fe/AHB composite material. It was determined that the values for Vickers hardness, Brinell hardness and indentation modulus increased by 142.03%, 69.32% and 144.11%, respectively, in the levels where the properties of the composite material were optimized compared to pure Fe material. As a result of the qualitative examination of all samples after storage in a comfortable environment without daylight, it was also observed that the anhydrous borax additive delayed the corrosion time of pure iron material.

Effect of V and Mn addition on the HAZ softening and tensile properties of friction stir welded martensitic steel

This study explores the suppression of heat-affected zone (HAZ) softening in friction stir welding (FSW) joints formed above the A3 temperature of martensitic steels by leveraging short-time secondary hardening induced by vanadium (V) addition. The HAZ microstructure was examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atom probe tomography (APT). Mechanical properties were evaluated through Vickers hardness (HV) measurements and tensile tests. Analysis of hardness distribution indicates effective HAZ softening suppression with V addition, attributed to the precipitation of fine and high-density V carbides within the HAZ. The inhibition of HAZ softening was correlated not only with V content but also with the A1 temperature of the steels, regulated by the manganese (Mn) content. However, at 1 mass% V content, intergranular brittle fracture occurred within the HAZ due to continuously distributed fine carbides and Mn segregation along the prior austenite boundary.

Evolution of fundamental mechanical properties with aliovalent Co/Cu partial substitution and preparation method for Y-123 system

This study investigates the effect of aliovalent Co/Cu replacement and preparation method on fundamental mechanical performance features of YBa2Cu3−xCoxO7−δ (Y-123) ceramic system depending on the crack propagation mechanism by Vickers hardness measurements (Hv) and mechanical investigation models for the first time. All the findings are verified by the scanning electron microscopy (SEM) examinations. Besides, the electron-dispersive X-ray (EDX) technique verifies the successful substitution mechanism. Besides, the Vickers hardness parameters improve systematically with the increment in the Co/Cu partial substitution (serving as a barrier) level due to formation of operable slip systems, ionic bond formations, and decrement of stress-amplified strain fields. Moreover, the Y-123 ceramic produced by solid-state reaction method and molecular weight of 0.20% presents the densest and smoothest surface morphology with the largest particle distributions and well-linked cobblestone-like grains. On the other hand, the Y-123 ceramic compounds produced by the sol–gel method are more sensitive and responsive to the indentation test loads. All the findings are wholly supported by the mechanical performance properties, including the shear modulus, resilience, and degree of granularity. Furthermore, the mechanical models indicate that every compound prepared exhibits the untypical reverse indentation size effect (RISE). Additionally, the modeling studies display that the induced cracking (IIC) approach is found to be the most appropriate method to examine true Vickers hardness parameters in the plateau limit regions. All in all, this comprehensive study reports efficiently exploiting the process–structure–property relationships in Y-123 ceramic material design for physical science and mechanical application fields using the aliovalent partial substitution and preparation condition.

Microstructural Investigations of Weld Deposits from Manganese Austenitic Alloy on X2CrNiMoN22-5-3 Duplex Stainless Steel

Duplex stainless steels are materials with high performance under mechanical stress and stress corrosion in chloride ion environments. Despite being used in many new applications such as components for offshore drilling platforms as well as in the chemical and petrochemical industry, the automotive industry, etc., they face issues of wear and hardness that limit current applications and prevent the creation of new use opportunities. To address these shortcomings, it is proposed to develop a hardfacing process by a special welding technique using a universal TIG source adapted for manual welding with a pulsed current, and a manganese austenitic alloy electrode as filler material. The opportunity to deposit layers of manganese austenitic steel through welding creates advantages related to the possibility of achieving high mechanical characteristics of this steel exclusively in the working area of the part, while the substrate material will not undergo significant changes in chemical composition. As a result of the high strain hardening rate, assisted mainly by mechanical twinning, manganese austenitic alloys having a face-centered cubic crystal lattice (f.c.c) and low stacking fault energy (SFE = 20–40 mJ/m2) at room temperature, exhibit high wear resistance and exceptional toughness. Following cold deformation, the hardness of the deposited metal increases to 465 HV5–490 HV5. The microstructural characteristics were investigated through optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and Vickers hardness measurements (HV). The obtained results highlighted the feasibility of forming hard coatings on duplex stainless steel substrates.

Nanostructuring of Additively Manufactured 316L Stainless Steel via High-Pressure Torsion for Enhanced Strength and Corrosion Performance

Bulk nanostructured materials (BNM) are defined as metallic materials with grain sizes <100 nm and are known to possess superior mechanical and functional properties compared to those with grain sizes in the micron and millimeter ranges. In this study, high-pressure torsion (HPT), a nanostructuring approach that imposes compressive stress and extreme torsional strain on bulk materials is applied to an additively manufactured (AM) 316L stainless steel (316L SS) for 10 revolutions. The grain sizes, hardness, and corrosion performance before and after HPT are evaluated by using extensive microscopy techniques, Vickers hardness (HV) measurements, and electrochemical tests conducted in 3.5 wt.% NaCl solution, respectively. The results show that after 10 HPT revolutions, nano-sized grains (average: ~42 nm) are obtained, whereas a three-fold increase in HV values from ~220 HV to ~600 HV are observed. Furthermore, the corrosion performance is also significantly enhanced as indicated by the reduction in corrosion ratefrom 2.53 μm/year initially, to 0.48 μm/year after HPT processing. These results highlight the benefits of HPT in producing bulk nanostructured materials with remarkably high hardness and excellent corrosion performance, potentially useful for a myriad of applications.

Cu–Mg dilute alloys- Assessment of strengthening, internal friction, and electrical conductivity

Overcoming the strength-conductivity trade-off has long been an issue for commercial copper alloys. However, a synergy between strength and electrical conductivity can be achieved by reasonable adjustment of the microstructure. It is known that the formation of Short-Range Order (SRO) in a solid solution can change the mechanical and electrical behavior of the materials. Currently, the prediction of SRO formation is widely based on computational techniques. In the present study, Miedema's thermodynamical approach is applied for the assessment of alloying elements' potential to form SRO in the copper lattice. According to this methodology, magnesium tends to form SRO with copper. The mechanical, electrical, and structural properties of the oxygen-free copper (Cu-OFC), Cu–Mg0.14 wt%, and Cu–Mg0.50 wt% strips fabricated by continuous extrusion forming process (Conform) have been investigated. According to the optical microscopy investigations, the average grain sizes of the Mg alloyed samples were observed to be lower compared to that of OFC. The Vickers hardness measurements were carried out and the hardness values for Cu-OFC, Cu–Mg0.14, and Cu–Mg0.50 samples were recorded as 56.3 HV, 76.05 HV, and 87.68 HV, and the yield strengths as 80, 150 and 260 MPa, respectively. A decrement in electrical conductivity was observed with the increasing Mg addition. Dynamic elastic modulus test measurements, which refer to internal friction, have been performed by impulse excitation technique to elucidate the presence of SRO in the dilute Cu–Mg systems. The anomalous “bump” formation in the temperature-elastic modulus profiles of the Cu–Mg samples was remarkable which has been attributed to the SRO formation.

Tailoring the structural, morphological, surface wettability and hardness features of Makrofol HS for surface applications: effect of DBD treatment

ABSTRACT In current research, Makrofol HS polymeric films have been utilized to evaluate the alterations in the surface properties under an atmospheric-pressure dielectric barrier discharge (DBD) plasma source. Upon DBD plasma exposure with various exposure durations ranging from 10 min to 120 min, the structural, surface wettability, surface free energy, surface roughness, and hardness features of Makrofol HS films have been studied and analyzed using different techniques. The FTIR spectra demonstrated that small changes in the band intensities correspond to the C-O-C as well as C=O bonds. Further, the changes in the absorption bands are correlated to the treatment time, leading to two critical processes, degradation, and crosslinking. The results of surface wettability displayed that the liquids' contact angle decreased from 84 ± 3o, 77 ± 3o and 62 ± 2o for water, glycerol, and dimethyl to 45 ± 1o, 42 ± 1o, and 36 ± 1o for untreated and treated samples at the highest treatment time, respectively. Also, the surface free energy significantly amended with increasing plasma exposure time. This modification in the treated surface indicates the increase in the polar groups on the treated surfaces, which then become hydrophilic surfaces. The samples' surface roughness parameters Ra, Rq, and Rz increased from 0.057 ± 0.003, 0.084 ± 0.004 and 0.366 ± 0.02 mm for untreated samples to 1.463 ± 0.073, 1.707 ± 0.085, and 6.839 ± 0.34 mm for treated samples at the highest treatment time, respectively. The Vickers hardness measurements showed an increase in the Vickers hardness from 12.31 ± 0.61 kgf/mm2 for the untreated sample to 44.89 ± 2.24 kgf/mm2 for the treated sample at the highest duration.

Mechanical Properties of Nano-Crystalline Glass-Carbomer Cements Used in Dentistry.

The main aim of this study was to assess the impact of the environment on the mechanical and tribological properties of glass-carbomer cements used in dentistry. The properties of the Glass Cements Polyalkene (GCP) Glass Fill material, belonging to glass-polyalkene cements, were tested after placing it in various environments: air, distilled water, artificial saliva simulating a neutral environment (pH = 7), and simulating inflammation (pH = 4). The research material included four samples and a two-year reference material. The analysis of volumetric consumption and the assessment of the impact of solubility on the stability of glass-carbomer cements were carried out using tribological measurements and Vickers hardness measurements. In addition, microstructural characterization of the materials was performed using scanning electron microscopy (SEM). It was observed that the lowest wear (0.04%), the most stable microstructure, and the lowest average hardness (21.52 HV 0.1) were exhibited by the material stored in artificial saliva simulating a neutral environment (pH = 7). The least stable microstructure and statistically the highest hardness (77.3 HV 0.1) was observed in the test sample, which was stored in air for two years and then in distilled water. The highest consumption (0.11%) was recorded in the case of cement placed in artificial saliva simulating inflammation (pH = 4). The results obtained in this study indicate specific trends in the influence of the environment in which the tested cement is located, such as air, distilled water, air/distilled water, artificial saliva simulating a neutral environment, and simulating inflammation, on its structure, hardness, and wear.

Impact of CAD/CAM Material Thickness and Translucency on the Polymerization of Dual-Cure Resin Cement in Endocrowns.

The objective of this study is to evaluate the impact of the thickness and translucency of various computer-aided design/computer-aided manufacturing (CAD/CAM) materials on the polymerization of dual-cure resin cement in endocrown restorations. Three commercially available CAD/CAM materials-lithium disilicate glass (e.max CAD), resin composite (CERASMART), and a polymer-infiltrated ceramic network (ENAMIC)-were cut into plates with five different thicknesses (1.5, 3.5, 5.5, 7.5, and 9.5 mm) in both high-translucency (HT) and low-translucency (LT) grades. Panavia V5, a commercial dual-cure resin cement, was polymerized through each plate by light irradiation. Post-polymerization treatment was performed by aging at 37 °C for 24 h under light-shielding conditions. The degree of conversion and Vickers hardness measurements were used to characterize the polymerization of the cement. The findings revealed a significant decrease in both the degree of conversion and Vickers hardness with increasing thickness across all CAD/CAM materials. Notably, while the differences in the degree of conversion and Vickers hardness between the HT and LT grades of each material were significant immediately after photoirradiation, these differences became smaller after post-polymerization treatment. Significant differences were observed between samples with a 1.5 mm thickness (conventional crowns) and those with a 5.5 mm or greater thickness (endocrowns), even after post-polymerization treatment. These results suggest that dual-cure resin cement in endocrown restorations undergoes insufficient polymerization.

Effect of Molybdenum on the Mechanical and Corrosion Properties of Ti-xMo-2Fe Beta Alloys

Titanium alloys are currently used in offshore industries. The titanium alloys used in offshore plants need to have excellent corrosion resistance and mechanical properties because offshore plants are exposed to harsh corrosive environments. At this time, the Ti-6Al-4V ELI alloy is mainly used in offshore plants because it has excellent mechanical properties and corrosion resistance. However, Ti-6Al-4V ELI alloy has the disadvantage of poor formability. To improve this, studies on metastable beta-Titanium alloys with a BCC structure are being actively conducted. In this study, a metastable beta-titanium alloy was fabricated using Mo, which is inexpensive and improves corrosion resistance, and Fe, which improves strength, among the titanium beta stabilizer elements. After the Ti-6Al-4V ELI and Ti-xMo-2Fe alloys solution treatments, electrochemical corrosion experiments were conducted to analyze corrosion characteristics, and mechanical properties were also analyzed through compression tests at room temperature and Vickers hardness measurement. Corrosion properties and the mechanical properties of Ti-xMo-2Fe alloy were considered in connect experiments such as microstructure analysis and hardness measurement. It was confirmed that the corrosion resistance of the Ti-xMo-2Fe alloy was better than that of the Ti-6Al-4V ELI alloy, and it was confirmed that the compressive strength and elongation rate of Ti-xMo-2Fe with its BCC structure get higher than Ti-6Al-4V ELI alloy.

A brief study of electrical and biological properties of BNT6BT/ZnO-HA Composite

The discovery of the piezoelectric properties of natural bone and their influence on bone growth within scaffolds has spurred researchers to investigate a range of bio-piezoelectric composite materials. By exploring these materials, researchers aim to better understand how piezoelectricity can be harnessed to promote bone growth and tissue regeneration, potentially leading to new breakthroughs in the field of regenerative medicine. In this study, the piezoelectric material, Bi0.5Na0.5TiO3-0.6BaTiO3/nano ZnO (BNT6BT/ZnO) and the biological hydroxyapatite (HA) were separately synthesized using the sol-gel method. The composite samples consisting of BNT6BT/ZnO and HA were fabricated using isostatic cold pressing. The composition and phase structure were studied using the X-ray diffraction (XRD) analysis, and the scanning electron microscopy (SEM) was used to study the microstructure and morphology. The presence of different phases and the distribution of elements were examined using EDAX elemental analysis and its corresponding maps. Among the composite samples the one containing 10 wt% HA (BNT6BT/ZnO-10HA) possessed the best dielectric properties. The Vickers hardness measurements showed that the addition of HA to the piezoelectric phase BNT6BT/ZnO results in higher hardness values, which expects to increase the fracture toughness of HA due to the higher elastic modulus to hardness ratio (E/H) of composite samples compared to pure HA. The in vitro bioactivity of the samples was tested in simulated body fluid (SBF) solution and the cell culture analysis was performed to examine the biocompatibility of the samples. Accordingly, apatite was deposited on the surface of the samples and all of the composite samples were bioactive. Furthermore, the BNT6BT/ZnO-10HA sample containing the largest amount of deposit showed the highest optical density (OD) in the MTT test.

Effect of duration and infection control barriers of light curing unit on hardness of Bulk Fill composite resin.

This study aimed to investigate the impact of the duration of light curing unit (LCU) usage and the use of infection control barriers on the hardness of Bulk Fill composite resin after curing. The hypotheses were that extended usage of the LCU would not reduces its output power and resin hardness, and that the presence of polyethylene film barriers exacerbates the reduction in resin hardness. Based on the absence or presence of polyethylene film (PE) and the number of layers used, a 3M LED curing light (EliparTM DeepCure-S; 3M ESPE, St Paul, MN, USA) was divided into three groups: PE0, PE1, and PE3. The curing light was used 30 times daily for 20 s per exposure, at frequencies of 0, 6, and 12 months. Maximum output power tests were conducted for each group of curing lights. Custom-made plastic modules were used to stack Bulk Fill composite resin (Filtek Bulk Fill Posterior Restorative; 3M ESPE) to a thickness of 4 mm. Each group of curing lights was used to cure the modules in a direct contact manner for 20 s. Vickers hardness measurements were taken at the top and bottom surfaces of the resin specimens using a digital microhardness tester. A one-way or two-way ANOVA analyzed the power of LCUs, Vickers hardness of Bulk Fill composite resin, and hardness decrease percentage across groups. Pairwise comparisons used the Tukey test (α = 0.05). As the duration of usage increased, both the power of the curing light and the hardness of the resin significantly decreased. Significant differences were observed in power and resin hardness among the PE0, PE1, and PE3 groups. When the duration of usage was 6 months or less, only multi-layered PE films led to a significant increase in the percentage decrease of hardness of cured resin from top to bottom. However, at 12 months, both single-layer and multi-layered PE films resulted in a significant increase in the percentage decrease of hardness of cured resin from top to bottom. The output power of the light curing unit decreases with prolonged usage, thereby failing to meet the curing requirements of Bulk Fill composite resin. The use of single-layer PE as an infection control barrier is recommended.