Vickers Microhardness Measurements Research Articles

Boron-modified super duplex stainless steels: microstructure, hardness, and industrial applications

In this work was investigated the boron modified super duplex stainless steel processed by spray-forming, to characterize the workpiece using different techniques, among them, optical microscopy, SEM-FEG, X-ray diffraction, Rama spectroscopy and Vickers hardness (VH) and Thermo-Calc software. As result, in this research was verified that in the ferrite phase the Cr element predominates, but in the austenite phase the Fe and Ni elements prevail by the EDS technique. As well as XRD spectra showed different meta-stable phases and (FeCr)2B phase. Besides, the Vickers microhardness measurement was around 460 HV, being much taller than the duplex stainless steel. This alloy can be successfully used in the chemical, oil and gas industries, petrochemical process plants, the pulp and paper industry, pollution control equipment, transportation and for general engineering thanks to their outstanding corrosion resistance and mechanical properties.

Crystal Growth, Linear Optical, Thermal, Mechanical and Third-order Nonlinear Optical Properties of 1,3-diphenyl prop-2-en-1-one Single Crystals

This work brings out the viability of the chalcone derivative (E)-1,3-diphenyl-2-propen-1-one (DPP) for industrial applications in nonlinear optical technology and device fabrication, though investigations on its crystal structure and nonlinear optical properties. The unit cell features of the DPP single crystals grown by slow evaporation solution growth method have been determined and hkl values indexed. The optical transparency of DPP in the near infrared and visible range is found to be admirable and an optical bandgap of 3.42 eV is revealed by the UV-Vis-NIR analysis. The work hardening coefficient (n) of DPP, determined as 2 from Vickers microhardness measurement, shows the moderate mechanical strength of the crystal. The Laser Damage Threshold value of 3.9 GW/cm2 sheds light on the high tolerance of DPP to optical damage and suggests its suitability in device fabrication. The potential of DPP crystal in nonlinear optical applications is suggested from its superior value of 1.16×10−7 esu for third order susceptibility and appealing values of other nonlinear optical parameters.

Microstructures, physical and corrosion behavior of NiCoFeCu high-entropy alloy nanocomposite coatings electro-co-deposited with nano-Si3N4 particles

High-entropy alloys (HEAs) have gained increasing attention over the decades, owing to their distinctive properties. Electrodeposition stands out as a cost-effective and convenient method for producing diverse types of HEAs. However, there's little attention paid to fabricating ceramic-enhanced HEA composites. In this study, NiFeCoCu/Si3N4 HEA nanocomposites were electro-co-deposited in an aqueous solution with varying loadings of Si3N4 nanoparticles and current densities. The morphological, elemental, and phase-structure characteristics were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) techniques. The Vickers-microhardness measurements, reciprocal wear, and electrochemical tests were conducted to evaluate the physical and anti-corrosion performance of the composite coatings. The findings indicate that the incorporation of Si3N4 nanoparticles not only changes the surface morphologies, compositions, and textures of the HEA matrix but also significantly enhances both the wear and anti-corrosion performance in artificial water by refining the microstructures and reducing the defects of the composite coatings. The HEA-3 g/L-Si3N4-40 mA/cm2 and HEA-6 g/L-Si3N4-40 mA/cm2 composite coatings demonstrate the best wear performance and anti-corrosion properties among the samples investigated, respectively. The present study shows a significant improvement in the mechanical and anti-corrosion properties of HEA coatings by incorporation of Si3N4 nanoparticles, which is a very promising approach for the surface protection of engineering materials used in corrosive and frictional-working conditions.

Comparison of various chitosan-based in situ forming gels with sodium fluoride varnish for enamel biomineralization: an in-vitro pH cycling model

This study aimed to evaluate chitosan (CS)-based formulations loaded with 5% sodium fluoride (NaF) and/or 10% nanohydroxyapatite (nHA) to remineralize the demineralized primary tooth enamel surface. Ninety enamel blocks were demineralized and were divided into six groups (n = 15): (1) CS-based hydrogel, (2) CS-based hydrogel loaded with NaF, (3) CS-based hydrogel loaded with nHA, (4) CS-based hydrogel loaded with NaF and nHA, (5) 5% NaF varnish, and (6) negative control with no intervention. After intervention, the specimens were pH cycled by 2 h immersion in demineralizing solution and 22 h immersion in remineralizing solution for 8 days. The remineralization effects were evaluated by Vickers microhardness measurements and field emission scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (FESEM-EDS). The best mean ± SD percentage microhardness recovery in remineralized enamel (%REMH) was found in group 4 (56.90 ± 5.49). The %REMH of groups 2 (30.74 ± 3.51) and 5 (29.23 ± 5.65) were statistically the same (p = 0.943). FESEM images confirmed partial coverage of the porous demineralized enamel with a newly formed mineralized layer. Based on EDS findings, the Ca/P ratio values of the treated enamel surfaces with CS-based hydrogels ranged between 1.71 and 1.87, and the highest F content was noticed in group 2 (1.02 ± 0.03). Although, all tested CS-based hydrogels demonstrated the potential to repair demineralized enamel, nHA- and NaF-containing CS-based hydrogel showed the highest remineralization effect. We infer that this new hybrid hydrogel is a potentially useful dental material for tooth biomineralization.

Effect of processing sequences in multi-pass friction stir processing on microstructure, microtexture and microhardness of 6063 aluminum alloy

ABSTRACT Single and double direction stir processing sequences were employed and investigated by fixing all other FSP parameters. Optical microscopy (OM) was utilised to assess the size and geometry of the processed zone. EBSD was also employed to evaluate the microstructure and microtexture development in different regions of the processed zones. In addition, Vickers microhardness measurements were made to evaluate the hardness evolution across the processed zone for the two processing sequences. The results show that using a single direction processing sequence is preferable due to better grain refinement, mainly in all regions of the processed samples. Gradual improvement was observed in microhardness with each additional pass, stronger refinement, and homogeneous grains in the processed regions (stir and overlapping zones). In the first pass’s stir zone (SZ), the microhardness is approximately 42.5Hv, while it increases to an average of 43.4Hv in SZ2 of the second pass and 44.3Hv in SZ3 of the third pass. Furthermore, more resistance to plastic deformation (slip) and lower intensity of heat distribution when compared to the double direction. Therefore, the application of a single direction processing sequence can be beneficial in the welding of such aluminium alloys.

Effect of friction pressure on microstructure and mechanical properties of friction welded joint between alumina and 1100 aluminum alloy

Friction welding (FW) is a solid-state joining process that has received considerable attention in recent years due to its efficacy in joining similar and dissimilar materials. In this experimental study, dissimilar joints of alumina (Al2O3) ceramic and 1100 aluminum alloy were produced by friction welding. The objective was to investigate the impact of welding parameters on the mechanical and structural properties of the welded joints. Welding processes were conducted using a continuous drive friction welding (CDFW) machine, under different friction pressures (20, 34 and 45 MPa), whereas other welding parameters are kept constant. The strength and mechanical properties of the welded Joints were assessed by means of a three-point bending test and Vickers micro-hardness measurements. Furthermore, the microstructure of the Joints was examined using optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that friction pressure has a significant effect on the structural and mechanical properties of the joints.

Effect of Citric Acid Hard Anodizing on the Mechanical Properties and Corrosion Resistance of Different Aluminum Alloys.

Hard anodizing is used to improve the anodic films' mechanical qualities and aluminum alloys' corrosion resistance. Applications for anodic oxide coatings on aluminum alloys include the space environment. In this work, the aluminum alloys 2024-T3 (Al-Cu), 6061-T6 (Al-Mg-Si), and 7075-T6 (Al-Zn) were prepared by hard anodizing electrochemical treatment using citric and sulfur acid baths at different concentrations. The aim of the work is to observe the effect of citric acid on the microstructure of the substrate, the mechanical properties, the corrosion resistance, and the morphology of the hard anodic layers. Hard anodizing was performed on three different aluminum alloys using three citric-sulfuric acid mixtures for 60 min and using current densities of 3.0 and 4.5 A/dm2. Vickers microhardness (HV) measurements and scanning electron microscopy (SEM) were utilized to determine the mechanical characteristics and microstructure of the hard anodizing material, and electrochemical techniques to understand the corrosion kinetics. The result indicates that the aluminum alloy 6061-T6 (Al-Mg-Si) has the maximum hard-coat thickness and hardness. The oxidation of Zn and Mg during the anodizing process found in the 7075-T6 (Al-Zn) alloy promotes oxide formation. Because of the high copper concentration, the oxide layer that forms on the 2024-T6 (Al-Cu) Al alloy has the lowest thickness, hardness, and corrosion resistance. Citric and sulfuric acid solutions can be used to provide hard anodizing in a variety of aluminum alloys that have corrosion resistance and mechanical qualities on par with or better than traditional sulfuric acid anodizing.

Influence of distal-end heat treatment in the properties of heat-activated NiTi archwires.

The aim of this study was to evaluate the extent of property changes caused by heating the distal portion of heat-activated nickel-titanium (NiTi) wires. Forty preformed heat-activated NiTi archwires (3MUnitek, Monrovia, CA, USA) with anominal cross-section of 0.018″ were used in this study. The archwires were divided into acontrol group, not submitted to heat treatment and, thus, maintaining the as-received properties, and an experimental group, in which the archwires were submitted to heat treatment for distal bending at one end. Wire segments of control and experimental groups were submitted to differential scanning calorimetry (DSC) and Vickers microhardness measurements. The DSC results suggest local recrystallization and precipitate dissolution at the heat-treated tip, which decreases as the distance to the wire's tip increases. Vickers microhardness tests revealed significant changes for distances between 6and 8 mm from the wire's tip. Heating the distal portion of heat-activated NiTi archwires should be performed with care since this clinical procedure may compromise the performance of these wires to a distance of 8 mm from the archwire end. Heat treatment for distal bending in heat-activated NiTi archwires may be performed, with little impact on the areas adjacent to heat treatment. In cases presenting molars requiring significant orthodontic corrections, it should be preferred to apply other techniques to avoid archwire sliding, such as crimpable stops, or to have flame control to avoid placing aheat-treated section in the tubes of these molars.

Influence of nozzle temperatures on the microstructures and physical properties of 316L stainless steel parts additively manufactured by material extrusion

Purpose Material extrusion (ME) is a low-cost additive manufacturing (AM) technique that is capable of producing metallic components using desktop 3D printers through a three-step printing, debinding and sintering process to obtain fully dense metallic parts. However, research on ME AM, specifically fused filament fabrication (FFF) of 316L SS, has mainly focused on improving densification and mechanical properties during the post-printing stage; sintering parameters. Therefore, this study aims to investigate the effect of varying processing parameters during the initial printing stage, specifically nozzle temperatures, Tn (190°C–300°C) on the relative density, porosity, microstructures and microhardness of FFF 3D printed 316L SS. Design/methodology/approach Cube samples (25 x 25 x 25 mm) are printed via a low-cost Artillery Sidewinder X1 3D printer using a 316L SS filament comprising of metal-polymer binder mix by varying nozzle temperatures from 190 to 300°C. All samples are subjected to thermal debinding and sintering processes. The relative density of the sintered parts is determined based on the Archimedes Principle. Microscopy and analytical methods are conducted to evaluate the microstructures and phase compositions. Vickers microhardness (HV) measurements are used to assess the mechanical property. Finally, the correlation between relative density, microstructures and hardness is also reported. Findings The results from this study suggest a suitable temperature range of 195°C–205°C for the successful printing of 316L SS green parts with high dimensional accuracy. On the other hand, Tn = 200°C yields the highest relative density (97.6%) and highest hardness (292HV) in the sintered part, owing to the lowest porosity content (<3%) and the combination of the finest average grain size (∼47 µm) and the presence of Cr23C6 precipitates. However, increasing Tn = 205°C results in increased porosity percentage and grain coarsening, thereby reducing the HV values. Overall, these outcomes suggest that the microstructures and properties of sintered 316L SS parts fabricated by FFF AM could be significantly influenced even by adjusting the processing parameters during the initial printing stage only. Originality/value This paper addresses the gap by investigating the impact of initial FFF 3D printing parameters, particularly nozzle temperature, on the microstructures and physical characteristics of sintered FFF 316L SS parts. This study provides an understanding of the correlation between nozzle temperature and various factors such as dimensional integrity, densification level, microstructure and hardness of the fabricated parts.

Synthesis of an Ultra-high Hardness Nanostructured AlSi10Mg Alloy via A Hybrid Laser Powder Bed Fusion/High-Pressure Torsion Approach

The hybrid combination of laser powder bed fusion (L-PBF) and high-pressure torsion, respectively an additive manufacturing (AM) and severe plastic deformation (SPD) has recently emerged as an important field of study due to the ability to produce novel nanostructured metals/alloys with simultaneous enhancements in mechanical (hardness, yield and tensile strengths) and functional (corrosion and wear) performances. Pioneering studies on the hybrid L-PBF/HPT approach was focused on 316L stainless steel (316L SS) and AlCuMg alloys due to their widespread engineering applications. AlSi10Mg, an alloy widely used in the automotive industry is expected to benefit from this hybrid combination but has not been investigated before. Thus, this study aims to investigate the microstructural features and hardness of the nanostructured AlSi10Mg attained by the hybrid L-PBF/HPT technique via transmission electron microscopy (TEM) and Vickers microhardness (HV) measurements, respectively. The results showed novel microstructures, including nano-scale grain sizes (< 200 nm), nano-sized Mg2Si precipitates (~200 nm), and dense dislocation networks. The average hardness value was determined as 230 ± 20 HV, homogeneously distributed throughout the disk surface as indicated by the low deviation (error bar). The microstructures of L-PBF/HPT-synthesised AlSi10Mg are different and significantly refined than conventionally cast AlSi10Mg, which contributed to the two- to four-fold hardness (typical HV values of as-cast AlSi10Mg ranges from 60 – 68 HV) increase via grain boundary and dislocation strengthening mechanisms.

Stabilization of durable tetragonal phase and barrier regions in y-123 ceramic systems with partial substitution mechanism

This study examines the impact of Tb and Zn doping on the Y-123 superconducting system by analyzing crack propagation mechanisms through Vickers microhardness measurements. The measurements are conducted at various application forces ranging from 0.245 N to 2.940 N. The microhardness measurements are used to determine the role of impurity addition on Vickers hardness, modulus of elasticity, brittleness index, fracture toughness, and yield strengths. It is found that impurity ions serving as strong barrier regions improve the surface residual compressive stress sites and interactivity between the adjacent layers. Similarly, the sensitivity to the external forces reduce significantly with the substitution mechanism due to the induced new slip systems and ionic bond formations. Accordingly, all the mechanical performance properties are recorded to increase significantly with the impurity ions. Especially, the replacement of Zn by Cu ions in the Y-123 matrix exhibits higher resistance to failure, mechanical strength, and stabilization of the durable tetragonal phase. Accordingly, Zn/Cu substitution in Y-123 ceramics paves the way for the applications of ceramic compounds in the fields of heavy-industrial technology and industrial power systems. All the ceramic materials also exhibit indentation size effect feature based on the recovery mechanism. Additionally, load-independent microhardness parameters are semi-empirically modeled by Meyer's law, Hays-Kendall, indentation-induced cracking, elastic–plastic deformation, and proportional sample resistance model for the first time. According to the comparisons, the IIC model is identified as the most suitable for interpreting the real microhardness results of newly produced Y-123 ceramic matrices.

Influence of Copper Addition on the Mechanical Properties and Corrosion Resistance of Self-Hardening Secondary Aluminium Alloy AlZn10Si8Mg

Aluminium alloys have a wide range of applications, mainly due to their advantageous strength-to-weight ratio, denoted as specific strength and corrosion resistance. In recent decades, there has been a notable surge in the usage of recycled alloys, attributed to their reduced production costs and emissions. One of the conditions for secondary production is the optimal sorting of used scrap. Once the aluminium scrap has been melted, it is tough to reduce the content of the various additives. Copper is the primary alloying element in some aluminium alloys, which leads to an increased amount of copper in the aluminium scrap. Therefore, it is important to investigate its effect on the properties of aluminium alloys in which it is not commonly present. For this reason, this paper is concerned with the influence of copper on the microstructure and properties of the secondary aluminium alloy AlZn10Si8Mg. Specifically, it compares two melts of self-hardening AlZn10Si8Mg alloys differing in copper content (0.019% and 1.72%). A complex quantitative and metallographic analysis by optical and electron microscopy has been performed. Mechanical properties were investigated by tensile test, Brinell hardness, and Vickers microhardness measurements. The corrosion resistance of the individual melts was verified by the Audi test.

Microstructure, Hardness and EIS Evaluation of Ti-15Zr-5Nb Dental Alloy

Ti alloys have been widely used in biomedical applications due to their special properties. They have specific properties such as biocompatibility, biofunctionality and high corrosion resistance, which enable them to function inside the human body. Among them, Ti-6Al-4V is probably one of the most widely used alloys for implants. However, aluminum and vanadium ions have been reported to cause problems and adverse reactions in the human body over long periods. Thus, in the present study, Ti–15Zr–10Nb alloy synthesized by high vacuum melting was manufactured and characterized by different techniques. The phase composition was determined by XRD. This showed the presence of α and β phases in the alloy, consistent with the microstructural study. From a microstructural point of view, the alloy shows lamellar and acicular structures with α-grain boundaries. Vickers microhardness measurements showed an increased hardness compared to Ti-CP. Furthermore, the electrochemical behavior was evaluated using HCl as an electrolyte. The obtained results were compared to Ti-CP tested in the same electrochemical condition. The studies indicated that Ti-CP presents a nobler electrochemical behavior than Ti-15Zr-5Nb. Thus, despite the very good corrosion properties of Ti-15Zr-5Nb in a simulated oral environment and Ringer’s solutions, the present study reveals that the Ti-15Zr-5Nb alloy has lower corrosion resistance in aggressive media when compared to Ti-CP.

Contribution of EBSD for the Microstructural Study of Archaeological Iron Alloy Artefacts from the Archaeological Site of Loiola (Biscay, Northern Spain)

Iron palaeometallurgy was carried out on three artefacts, classified as nails and excavated from the archaeological site of Loiola (La Arboleda, Biscay, northern Spain), to investigate Roman manufacturing techniques. Energy Dispersive Spectroscopy (EDS) coupled with Environmental Scanning Electron Microscopy (ESEM) and micro-Raman spectroscopy were used to obtain elemental composition and structural characterization of mineral phases. Metallurgical properties and crystallographic texture were studied by combining microscopic methods such as optical microscopy (OM), Electron Backscatter Diffraction realized in environmental mode (EBSD) and measurements of local Vickers microhardness. The three artefacts had different microstructures, distinguished by a large gradient of carbon content, although important segregations (inclusions) were observed in all of them. Two pearlite-rich artefacts showed a high density of structural defects (geometrically necessary dislocations and large crystallographic orientation gradients in pearlitic ferrite, curved pearlitic cementite) resulting from a high level of plastic deformation that occurred during the manufacturing process. The third artefact consisted of pure ferrite without structural defects. This one was clearly manufactured differently from the two others, so it probably had another functionality.

Experimental and theoretical investigation on the SR method grown semi-organic Piperazinium Tetrachlorozincate Monohydrate (PTZM) single crystal for optoelectronic applications

Efficient semi organic nonlinear optical (NLO) Piperazinium Tetrachlorozincate monohydrate (PTZM) [C4H12N2][ZnCL4]·H2O single crystals have been grown by slow evaporation solution technique (SEST) and Sankaranarayanan-Ramasamy (SR) method using water as solvent. Single crystal X-ray diffraction (SXRD) analysis reveals the unit cell parameters of the grown crystal. The morphology of the grown crystal was identified by the single crystal XRD analysis. The electrical properties, dielectric constant, dielectric loss and piezoelectric (d33) coefficient were determined. The etch pit density of PTZM crystal has been calculated by using the chemical etching analysis. The laser damage threshold (LDT) analysis was investigated by Nd: YAG laser and the wavelength of laser is 1064 nm. The mechanical stability of the grown PTZM crystal was studied using Vickers microhardness measurement. Utilizing quantum chemical calculations, the PTZM compound is analyzed for vibrational properties, HOMO and LUMO characteristics, NBO interactions, and the determination of first-order hyperpolarizability. The nonlinear susceptibility and first-order hyperpolarizability results provide compelling evidence and affirm the PTZM molecule’s potential as a strong candidate for nonlinear optical (NLO) applications.

Influence of intermetallic phase (TiFe) on the microstructural evolution and mechanical properties of as-cast and quenched Ti–Mo–Fe alloys

This study presents the phase analysis, microstructural characteristics, and mechanical property evaluation of the as-cast and quenched Ti–15Mo–xFe alloys with high iron content ranging from 4 to 12 weight percent. All the four alloys were produced in a vacuum-arc melting furnace. Heat treatment in the form of solution treatment was performed in a muffle furnace at a temperature of 1100 °C, with 1-h holding time and the samples were rapidly quenched in ice-brine. X-ray diffractometer (XRD) was used to analyses the phases present in each alloy whereas the optical microscope (OM) was employed to track the microstructural evolution and percentage porosity. The mechanical properties of the alloys were evaluated using a tensile test and compression test method while the micro-Vickers hardness measurements were conducted to evaluate hardness of the alloys. The XRD patterns of as-cast showed peaks belonging to the β and α″ phases and intermetallic B2 TiFe phases. The as quenched XRD peaks illustrated β phase only and Fe·Ti·O2 phases. The as-cast OM micrographs revealed equiaxed β grains, substructures, dendritic structure, and pores forming around the grain boundaries. The quenched OM showed only β equiaxed grains with pores throughout the grain boundaries. The tensile properties such as ultimate tensile strength (UTS) and elastic modulus (E) of as-cast TMF0 were 264 MPa and 79 GPa respectively and these properties changed upon quenching to 411 MPa and 66 GPa respectively. The elastic modulus of TMF1 in as-cast condition was 74 GPa. The UTS and E of TMF1, TMF2, and TMF3 in as-cast and quenched conditions were not recorded due to the fragility of the samples that failed prior to yielding any useful data. The compressive strength in as-cast and in quenched condition decreased with an increase in Fe content. The micro-Vickers hardness in as-cast and quenched conditions showed a similar trend with hardness increasing slightly upon quenching for TMF0, TMF1, and TMF3 alloys but slightly decreased in the case of TMF2. The fracture surfaces of all the as-cast and quenched alloys were comprised of ductile and brittle fracture.

Mechanical properties of Ag-added DyBa2Cu3Oy superconducting melt-textured bulks prepared by the single-direction melt growth method

Ag-added DyBa2Cu3Oy superconducting melt-textured bulks were prepared using the newly developed single-direction melt growth (SDMG) method with different pre-heat-treatment conditions. Clearly distinct microstructures were observed depending on the pre-heat-treatment conditions and thickness of the bulks. Their mechanical properties were evaluated by use of Vickers microhardness measurements at varying applied forces. Vickers microhardness increases with an increase in the applied force for each sample, up to an importantly high value of ∼9 GPa at the saturated region, indicating all the prepared bulks demonstrate the untypical reverse indentation size effect (RISE) performance. In addition, the experimental results found from the saturation regions are examined by the mechanical methods such as Meyer's law, proportional sample resistance model, elastic/plastic deformation, Hays-Kendall (HK) approximation, and indentation-induced cracking (IIC) model. According to the mechanical modelling findings, the HK and IIC models are found as appropriate mechanical models describing the hardness values for all the studied bulks exhibiting RISE feature and the true values are suggested to lie between the estimated values of HK and IIC models.

Enhanced Microhardness and Corrosion Performance of Additively Manufactured Inconel 718 Specimens through Nanostructuring by Severe Plastic Deformation

Severe plastic deformation (SPD) processes, particularly high-pressure torsion (HPT) have been increasingly applied to metallic specimens fabricated by laser powder bed fusion (L-PBF) additive manufacturing (AM) for enhancing their mechanical and functional properties through nanoscale grain refinement (≤ 100 nm). In this study. L-PBF AM-fabricated Inconel 718 (IN 718) specimens are initially subjected to 10 HPT revolutions to produce nanosized grains. Subsequently, microstructural characterisation, as well as hardness and electrochemical tests are conducted to evaluate the evolution of microstructures, hardness, and corrosion performance of the as-received and HPT-processed specimens by using various microscopy, Vickers microhardness (HV) measurements, and corrosion performance, respectively. The results reveal an average grain size of ~ 46 nm, dense dislocation networks, and nanotwins after 10 HPT processing, which contribute to the two-fold hardness increase compared to the as-received condition. Such microstructures also contributed to the overall improved corrosion performance after 10 HPT processing, as quantified by the 83% and 73% reduction in corrosion rate and pitting potential, respectively.

Effect of nano-Al2O3 particle addition on Co–P–xAl2O3 nanocomposite plating electroplated on X65 steel

PurposeThe purpose of this study is to reveal the effect of nano-Al2O3 particle addition on the nucleation/growth kinetics, microhardness, wear resistance and corrosion resistance of Co–P–xAl2O3 nanocomposite plating.Design/methodology/approachThe kinetics and properties of Co–P–xAl2O3 nanocomposite plating prepared by electroplating were investigated by electrochemical measurements, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Vickers microhardness measurement, SRV5 friction and wear tester and atomic force microscopy.FindingsA 12 g/L nano-Al2O3 addition in the plating solution can transform the nucleation/growth kinetics of the plating from the 3D progressive model to the 3D instantaneous model. The microhardness of the plating increased with the increase of nano-Al2O3 content in plating. The wear resistance of the plating did not adhere strictly to Archard’s law. An even and denser corrosion product film was generated due to the finer grains, with a high corrosion resistance.Originality/valueThe effect of different nano-Al2O3 addition on the nucleation/growth kinetics and properties of Co–P–xAl2O3 nanocomposite plating was investigated, and an anticorrosion mechanism of Co–P–xAl2O3 nanocomposite plating was proposed.

Archaeometallurgical Study of a 16th–17th Century “Rapier” Sword Manufactured in Caino (Northern Italy)

AbstractA metallurgical study was performed on a 16th–17th century “rapier” sword manufactured in Caino (northern Italy). Metallographic investigations and Vickers microhardness measurements indicate that the rapier was forged by assembling via hammer-welding different hypoeutectoid and near eutectoid steel bars. The rapier blade was heat treated by slack-quenching to increase its hardness, especially near the blade tip, improving the thrusting performance. The chemical composition of slag inclusions was analyzed by scanning electron microscopy coupled with X-ray dispersive spectroscopy. Compositional data of slag inclusions were analyzed by a multivariate statistical strategy aimed to distinguish and classify slag inclusions on the basis of their origin. It was estimated that the temperature reached during the finery and forging processes was at least 1270 °C and 1160 °C, respectively.