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The effect of 2MeV energy electrons with fluences from $0.5\times 10^{17}$ to $4.0\times 10^{17}$ electron/cm² on the crystal structure, surface morphology, absorption spectrum, band gap, Raman spectrum and microhardness of ZnS crystal was investigated. The crystal structure of ZnS is face-centered cubic with space group F-43m. Upon irradiation with a fluence of $4\times 10^{17}$ electron/cm², the unit cell parameter decreased by 0.0195Å, and the coordinates of the Zn${}^{+2}$ ions were changed. Irradiation with fluences ranging from $0.5\times 10^{17}$ to $4\times 10^{17}$ electron/cm² increased crystallite size from 20nm to 28nm. The study of the surface morphology of the ZnS single-crystal revealed that irradiation caused a reduction in both the width ($R_a$) and height ($R_z$) of the surface roughness. The band gap of the ZnS single-crystal decreased from 3.521 to 3.506eV when irradiated with fluence electrons from $0.5\times 10^{17}$ to $2.5\times 10^{17}$electron/cm². Raman spectrum observations showed an increase in the longitudinal optical (LO) mode peak (350cm${}^{-1}$) intensity following the irradiation of ZnS single-crystal with electrons. The microhardness of the ZnS single-crystal showed an exponential increase by 20% when irradiated with fluences from $0.5\times 10^{17}$ to $2.5\times 10^{17}$electron/cm².

The machinability of aluminum alloy (Al-6082) has the scope of enhancement by integrating Friction Stir Processing (FSP) with tool geometry, tool shape and different tool materials. In this research, the role of tool pin shape has been studied by experimenting on various tool shapes (square, hexagonal and octagonal) with the aim of machinability improvement. In FSP, the tool rotation speed is 930rpm and tool travel speed is 26mm/min. The specimens have undergone tensile, microhardness and microstructure testing using optical microscope and scanning electron microscopy. The percentage elongation has been increased from 15% to 29% in the case of the octagonal-shaped tool pin; similarly, the (Vickers’) microhardness value is 14.6% higher than the square- and hexagonal-shaped tool pins. Among these tool pin shapes, the octagonal-shaped tool pin succeeded in providing the best-in-class machinability performance on Al-6082 T6 alloy with FSP. It may unveil the newer scopes of FSP on Al-6082 for automotive components assembly and other similar applications.

This study examined the microstructural, mechanical, and corrosion behaviors of a multidirectional-forged (MDF) Mg–Zn–Ca alloy. The results showed significant grain refinement of the alloy after 5 passes of the MDF process from 378$\mu$m to 23$\mu$m. X-ray diffraction analysis (XRD) revealed the presence of finer Mg₇Zn₃ phases and $\alpha$-Mg and Ca₅Zn₃ phases after the MDF process and peak shift and broadening. Higher hardness ($76.46\pm 3$) was noticed in the MDF 3 pass sample due to grain refinement; further hardness slightly decreased due to texture softening. Moreover, the results of the in vitro corrosion experiments conducted in SBF solution showed that the corrosion current densities of the alloys move in a noble direction as the number of MDF passes increases. MDF 3 pass sample (0.00523mm/y) showed the lowest degradation rates compared to the as-cast sample (0.01154mm/y), attributed to refining and redistributing the second phases.

Laser-based surface enhancement techniques improve metals’ mechanical properties. Laser Hardening (LH) and Laser Shock Peening (LSP) techniques are effective particularly well with low-alloy steel made of 34Ni-Cr-Mo6, which is a type of steel alloy that is put to use in a wide variety of fields because it possesses excellent levels of both strength and toughness. For specific applications, the laser can be shaped into line or spherical beams. On the other hand, typical industrial requirements of low alloy steel components like 34Ni-Cr-Mo6 are enhanced hardness and mechanical strength with minimum or no distortion. A 3 kW high power fiber laser with a flat top-hat beam of dimension $30\times 1$mm and a circular beam of Ø6mm are employed in this study. Investigation into the effects of repeated LSP on the microstructures and residual stress of 34Ni-Cr-Mo6 low alloy steel was also done. LSP treatment is carried out at 6.36GWcm${}^{-2}$ Laser Power Density (LPD) with different laser impacts, i.e. single and double, by keeping 0% overlap along the scanning direction and perpendicular directions, respectively. The shock-peened samples were characterized in terms of residual stress measurements and microstructural evolution using different characterization techniques. A substantial improvement in compressive residual stress was observed at the hardened cross-section i.e. $\sim -260$MPa and at shock peened surface $\sim -620$MPa respectively as compared to the as-received sample ($\sim -100$MPa). LH samples showed a better result in terms of microhardness values when compared to shock peened samples i.e. for LH, the microhardness values at the cross-section were $\sim 710\pm 40$HV${}_{0.5}$ nearly 2.5 times increase in hardness. Extreme plastic deformation was found by microstructural examination of cross-sections of LSP-treated areas. Hardness was nearly marginally improved in multiple times LSP-treated samples compared to unpeened ones as a result of LSP.

In this study, the tribological behavior of Tungsten Inert Gas (TIG) welded Inconel 617 alloy has been studied using the Pin-on-disc tribometer. TIG welding was performed after imparting surface coatings to the Inconel 617 alloy which was coated with a blend of Silicon dioxide (SiO₂) and Titanium dioxide (TiO₂) in different proportions. Three samples were prepared by varying the coating composition and weld current. The Coefficient of Friction (COF), wear depth ($\mu$m) and hardness of the samples were estimated. Microstructure analysis and X-ray diffraction (XRD) analysis were also carried out on the samples. The wear depth of the Inconel 617 substrate, as well as weld bead samples 1, 2, and 3, were 2055.1, 415.39, 463.17, and 560.68 $\mu$m respectively. The COF for the Inconel 617 substrate and weld bead samples 1, 2, and 3 were determined as 0.384, 0.491, 0.471, and 0.455 respectively. By analyzing the results of the wear test, it was observed that ‘sample 1’ welded at the lowest heat input of 4.32 kJ/mm, exhibited superior tribological characteristics including reduced wear (415.39 $\mu$m) and an increased COF (0.491) compared to the other samples. The enhanced tribological performance could be attributed to factors such as the presence of carbides like TiC and notably the higher hardness (284.12HV) exhibited by ‘sample 1’.

Urea-doped barium tartrate (UBT) crystals were developed using the method of an aqueous solution. The crystal structure was determined through XRD analysis. Optical transmittance studies were conducted to analyze multiple linear optical parameters such as transmittance, band gap, refractive index, absorption coefficient and more. Vickers microhardness testing was performed to assess mechanical properties like hardness and yield strength. The efficiency of Second harmonic generation (SHG) was calculated for the harvested crystal. Laser damage threshold (LDT) testing was completed as well. Nonlinear optical characteristics were analyzed by applying the Z-scan method. Electronic polarizability was calculated for the UBT crystal.

Nanocrystalline pure metals with grain size below 10nm are very difficult to prepare. Alloying enables the production of such a fine grains, even down to an amorphous state. In this work, Ni-Mo nanocrystalline coatings were electrodeposited from a citrate-ammonia base solution using a direct current (DC) technique. The grain sizes were estimated from X-ray line broadening. Mo content of the coatings was determined by energy dispersive X-ray analysis (EDS). The results showed that the grain size decreased when the Mo content of alloy was increased through reducing the bath pH. The microhardness measurements showed an increase in hardness with decreasing the pH, a maximum hardness of 820 Vickers was obtained for the coating deposited at pH9 with a 17 wt% Mo. Although, at pH values lower than 9, alloys with higher than 17wt% Mo were obtained, a softening effect was observed despite the decrease in grain size which is the result of transition from a nanocrystalline to amorphous structure.

Microstructural characterization of as-cast and extruded experimental alloys as (A) Mg-6.86Li-3.02Al-1.12Ce-0.7Ca (B) Mg-8.15Li-3.07Al-1.12Ce-0.72Ca (C) Mg-10.54Li-3.54Al-1.23Ce-0.94Ca are researched in this paper. The results show that the as-cast specimens of (A) and (B) are composed of α (Mg) phase, β (Li) phase, rod-like and bulk Al₂Ce compound. On the other hand, β phase (Li), bulk and rod-like Al₂Ce compound, Al²Ca compound at boundaries are observed in the as-cast (C) alloy. The addition of Ce and Ca also shows in the microstructure the presence of Al-Ce-Ca phase, a solid solution of Ca in Al2Ce compound. In the extruding alloys, the microstructure is refined and the β phase has the effect of coordination during deformation. The long rod-like and the bulk compounds become short rods and fine clumps distributing evenly in the extruding direction after extruding process. The microstructure of extruded Mg-10.54Li-3.54Al-1.23Ce-0.94Ca alloy testified the existence of eutectic structure.

A metal matrix composite coating reinforced by ZrC-ZrB₂ particulates has been successfully fabricated utilizing the in situ reaction of Zr, B₄C and Fe pre-placed mixed powders by gas tungsten arc welding (GTAW) cladding process. Various volume fraction of ZrC-ZrB₂ particulates composite coatings were produced through cladding different weight ratios of Zr+B₄C (30%, 50%, 70%) to improve the wear resistance of AISI1020 steel substrate. The Microstructure of the coating was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrum (EDS), meantime microhardness and wear resistance at room temperature of the composite coating were examined by means of Microhardness Tester and Wear Tester, respectively. The results show that the main phases of the composite coating obtained by GTAW are ZrC, ZrB₂ and α-Fe, ZrC exhibits hexahedron and petal shapes, ZrC-ZrB₂ compound presents acicular and clubbed forms. With the increase of content of Zr+B₄C, the maximum volume fraction of ZrC-ZrB₂ particulates can reach 16.5%, microhardness is up to 1300HV, and wear resistance is about twenty times higher than that of AISI1020 steel substrate.

Experiments and numerical simulations were conducted to investigate flow behaviour of the specimen made of commercially pure aluminum alloy (AA1050) during multi-pass equal channel angular pressing (ECAP) for route A up to four passes. Influence of processing conditions on friction and flow behaviour was investigated by measuring load variations, microhardness distributions and microstructure changes depending on the number of passes. It was carefully simulated by employing the finite element technique by tracing the local deformation, determining the load requirement and comparing the local strain with microhardness distributions. Change of the grain size depending on the number of passes was monitored by transmission electron microscopy. The present work clearly showed flow characteristics of the deformed specimen at the central and surface regions due to the effect of the number of passes for the multi-pass ECAP.

Specimens of nanocrystalline pure gold were prepared by the gas deposition method. The formation of helium bubbles in the specimens and their annealing behavior were studied in order to confirm their effect on thermal stabilities of grain size and mechanical properties. The specimens with 10-25nm mean grain size were analyzed by transmission electron microscopy and X-ray diffraction methods. Spherical helium bubbles, about 5nm in diameter, were formed, the same as in the case of helium ion implantation. After annealing at 573K for 1h in vacuum, most of the bubbles had not disappeared and some were trapped at the grain boundaries. Larger numbers of bubbles were trapped at grain boundaries in the specimens with high thermal stability than for low thermal stability specimens. Helium bubbles trapped at grain boundaries can be considered as local barriers to grain growth and to contribute to thermal stability of mechanical properties.

In this work the purpose is, in addition to the determination of microhardness, to get some information about the effect of heat treatment on the microstructure of the magnetic Nd₁₅Fe₇₇B₈ alloy. For this study we have used an optical microscope and an electronic microprobe. The results show that the structure of the Nd₂Fe₁₄B phase, which confers good mechanical and magnetic properties on the alloy, is well tetragonal, as mentioned in several works. The morphology, the concentration and the quantity of this phase depend on the temperature of annealing. The microhardness of the phase has an average value between those of the other involved phases.

This paper discusses the optical and mechanical properties of triglycine sulphate (TGS) and MgCl₂ added TGS single crystals (McTGS) grown from aqueous solution at room temperature using slow evaporation solution growth technique. The grown crystals were characterized by powder X-ray diffraction technique and the cell parameter values are found to be a = 9.405 Å, b = 12.623 Å and c = 5.721 Å; β = 110.347° with V = 637.001 ų. UV-Vis-NIR study shows the direct type transition is involved in these materials and indirect, phonon energy gap of McTGS crystals have also been calculated, and these values are less than the TGS crystals. Refractive index and real and imaginary part of the dielectric constant have been discussed for grown crystals. The value of interband optical transition and oscillator energy has been determined by analyzing refractive index with incident energy. Vickers microhardness test was used to determine hardness number, fracture toughness, brittleness index, yield strength and types of crack formed in the crystals.

Zn and Zn–Bi coatings were electroplated on mild steel substrate by direct and pulse current (PC) techniques. The effects of Bi and deposition method on the phase, microstructure and mechanical properties of Zn-based coatings have been studied. Results showed that the crystal orientation and microstructure of Zn–Bi coatings were different compared to the pure Zn coating. By adding a small amount of Bi solution into Zn electrolyte, the microhardness of Zn–Bi coatings was increased by two times, and the wear volume loss was also decreased. Finer grain size and smoother surface can be achieved by utilizing PC deposition, resulting in better mechanical properties compared to the direct current (DC) deposition.

Copper (Cu) is widely used as electrical conducting and contacting material. However, Cu is soft and does not have good mechanical properties. In order to improve the hardness and wear resistance of Cu, sol-enhanced Cu–Al₂O₃ nanocomposite coatings were electroplated by adding a transparent Al oxide (Al₂O₃) sol into the traditional electroplating Cu solution. It was found that the microstructure and mechanical properties of the nanocomposite coatings were largely influenced by the Al₂O₃ sol concentration. The results show that the Al₂O₃ nanoparticle reinforced the composite coatings, resulting in significantly improved hardness and wear resistance in comparison with the pure Cu coatings. The coating prepared at the sol concentration of 3.93 mol/L had the best microhardness and wear resistance. The microhardness has been improved by ~20% from 145.5 HV (Vickers hardness number) of pure Cu coating to 173.3 HV of Cu–Al₂O₃ composite coatings. The wear resistance was also improved by ~84%, with the wear volume loss dropped from 3.2 × 10^-3 mm³ of Cu coating to 0.52 × 10^-3 mm³ of composite coatings. Adding excessive sol to the electrolyte deteriorated the properties.

The band structure of Al${}_x$Ga${}_{1-x}$Sb semiconducting ternary alloys and their related properties such as elastic constants, microhardness, transition pressure to the first phase, acoustic wave velocities and melting temperature have been investigated. The calculations are performed using a pseudopotential approach within the virtual crystal approximation which includes the effect of compositional disorder as an effective potential. Generally, our results are found to be in good accord with the experimental results. The composition dependence of all features of interest showed a monotonic behavior and suggests that the stiffness, hardness and structural stability becomes better in Al${}_x$Ga${}_{1-x}$Sb for higher Al concentrations. The bulk sound speeds and melting temperature are found to become larger when increasing the Al content.

The microstructure, microhardness and wear property of electroplated Ni–ZrO₂ nanocomposite coatings with different ZrO₂ concentration were analyzed using SEM, microhardness and wear tests. It was found that in the composite coatings, incorporation of ZrO₂ particles improves the mechanical property of Ni coatings and the effect of ZrO₂ nanoparticles concentration on the surface morphology, microstructure and mechanical property of electroplated coatings was discussed. The mechanical properties of Ni–ZrO₂ coatings reach the optimum value when the ZrO₂ concentration is 10 g/L.

Titanium nitride (TiN) thin films have excellent physical and chemical properties, and are widely used as cutting tools, drills and die protective coatings. However, their limited hardness and corrosion resistance caused by the rough, loose, columnar structure will affect its application in extreme environments. TiN films with refined grains and nanostructure might solve this problem. In this paper, Co and Cr atoms were doped into TiN film to tailor its structure. The effects of Co and Cr content on the Ti(CoCr)N film structure, mechanical properties and corrosion resistance were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), microhardness tester and electrochemical corrosion tester. The results show that Co and Cr doping can disturb the columnar growth of TiN films, and lead to refinement of TiN grains. Compared to TiN films without Co and Cr doping, the hardness of Ti(CoCr)N with 2.7 at.% Co and 1.9 at.% Cr increases by about 37% to 31.3 GPa. And Ti(CoCr)N films with 2.7 at.% Co and 1.9 at.% Cr have the best corrosion resistance.

In order to obtain a laser-cladded coating with no cracking and good corrosion resistance, this paper investigated laser cladding of a mixture of 17-4PH stainless steel and Ni60 powders on ASTM 1045 steel substrate. The surface cracking, mechanical properties and corrosion resistance of the coatings were assessed by various characterization methods. The experimental results demonstrated that a crack-free coating can be obtained by adding 30% (or above) 17-4PH stainless steel into Ni60 alloy. The mechanical properties of the coatings were determined by adding 17-4PH, but stabilized at about 79% of pure Ni60 alloy, which is acceptable considering the benefit of elimination of surface cracking. Decrease in the mechanical properties were caused by the dilution of the strengthening elements and reduction of population of hard phases. Composite coating having 30% of 17-4PH also exhibited the smallest corrosion current, lowest corrosion potential and slowest corrosion rate, and therefore the best corrosion resistance.

This paper evaluates the feasibility of using SiC and TiC as reinforcement particulates for titanium metal matrix composites (Ti-MMC). The SiC and TiC particles were coated with titanium using a chemical coating technology in order to achieve a homogeneous mixing when they were mixed with pristine Ti. The Ti-MMC with these specially prepared reinforcements were fabricated by a conventional press and sinter route. The effects of sintering temperature in Ti matrix were investigated with respect to phase constituents, microstructure and tribology properties. No in situ phases were observed during sintering and the reinforcement and matrix show sufficient bonding, which acts as a major parameter to enhance hardness and wear resistance compared to pure Ti. All the composite samples had a high sintered density. The hardness of the composites increased with an increase in the sintering temperature. It was also noticed that with the increase in the temperature ranging from $1200^{\circ }$C to $1300^{\circ }$C, improvement in the mechanical and tribological properties of the developed titanium matrix composites could be observed. The highest hardness value $385\pm 20{\mathrm{\text{HV}}}_1$ was recorded for Ti-2 wt.% Ti-coated SiC composite when sintered at $1300^{\circ }$C for 3 h.