Alloy Constituents Research Articles

Formal Relationship Between the Firearm “Memory Effect” and the Decay Time of the GSR Particles Present on the Shooter’s Hands

Background/Objectives: The Scanning Electron Microscope (SEM), combined with an Energy Dispersive Spectrometer (EDS), has been, for over fifty years of practical experience and research in the field, the analytical system of choice for the investigation and analysis of Gun Shot Residues (GSRs). However, the interpretation of analytical results has profoundly changed in recent decades. Specifically, the criteria for evaluating particles presumptive of contamination of a possible discharge have evolved, assessments regarding possible primary/secondary transfer phenomena have been refined, and the retention times of particulate matter on various types of surfaces involved during the discharge have been revalued. The purpose of this study is to provide a formal representation that links together the firearm memory effect, namely the formation of composite characteristic GSRs resulting from the use of the same Firearm but with ammunition having different metallic alloy constituents and different primer mixtures, and the decay time. Methods: The deduced mathematical model is based on experimental results reported in the scientific literature listed below, and it has been elaborated with a series of non-contradictory assumptions, each of which plays a specific role in the mathematical formalism used. Results and Conclusions: This model, although not yet validated through rigorous experimentation, represents a valuable tool in investigations related to the firearm memory effect when forensic specialists have collected GSR samples from the hands of the alleged shooter within four hours of the shooting.

Influence of pH on Indium Deposition Rates: A Comprehensive Electrochemical Analysis

Abstract Binary indium-tin (In-Sn) and ternary indium-tin-bismuth (In-Sn-Bi) alloys hold significant promise for reducing soldering temperatures in electronic assembly. However, traditional metallurgical methods are unsuitable for fabricating micro-solder joints, making alloy electroplating essential for fine-pitch interconnects. The co-electroplating of alloy constituents is often hindered by substantial differences in reduction potentials. Therefore, sequential electroplating followed by high-temperature reflow emerges as a more practical solution. Nonetheless, challenges persist, particularly due to the limited understanding of indium (In) deposition kinetics and its strong dependence on pH. This study investigates the influence of pH on In plating rates and overall deposition kinetics. The thickness and cross-sectional morphology of electroplated In films are analyzed across a pH range of 2.2–3.3, with plating conditions optimized to identify the most effective parameters. Structural properties, uniformity, and potential oxide inclusions in the electroplated films are assessed using X-ray diffraction and differential scanning calorimetry. Plating at pH 2.9 in a solution of 0.12M In₂(SO₄)₃ and 0.70M Na₂SO₄ produces the highest deposition rate and the most structurally homogeneous layers. Deviations from this optimal pH inevitably promote side reactions that markedly reduce deposition rates and compromise film quality.

Microstructural and Oxidation Effects of Nb Additions to U3Si2

U3Si2 is a long term, accident-tolerant nuclear fuel candidate for light-water reactors because of its superior thermal conductivity and increased uranium density when compared to traditional uranium dioxide (UO2). While reducing internal thermal stresses and increasing efficiency, U3Si2 exhibits energetic oxidation during certain off-normal and accident scenarios, which include coolant or steam exposure. To mitigate this, Nb is investigated as an alloy constituent to enhance corrosion resistance and increase mechanical strength. The work presented investigates the response of Nb-alloyed U3Si2 to steam atmospheres. A thermogravimetric analysis is conducted in flowing steam to T > 1000 °C to assess oxidation resistance. The phase characterization of as-melted, thermally annealed and post-oxidation compositions with up to 12 vol% Nb by powder X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy is reported.

New Electrochemical Approach for Synthesis of Nanoporous Silver

Cu-Ag alloy films were electrodeposited on Au substrates to serve as precursor alloys for synthesizing finely-structured nanoporous Ag (NPS) structures. Two innovative approaches, surface limited redox replacement (SLRR) and defect mediated growth (DMG) along with overpotential deposition (OPD), were comparatively utilized to fabricate Cu-Ag alloy films. The electrolyte for these novel approaches contained Pb2+ ions to serve either as a sacrificial metal to be replaced by the co-depositing Cu and Ag (in SLRR) or as mediating metal to facilitate the 2D growth of both alloy constituents (in DMG). The resulting alloy films from both approaches displayed superior uniformity and miscibility compared to the OPD alloy, as evidenced by electrochemical scanning electron microscopy (SEM) and X-ray diffraction characterization routines. In a subsequent step, NPS structures were generated through the de-alloying of as-deposited Cu-Ag alloys, as illustrated by SEM imaging that revealed ligament and pore sizes with a thickness in the ballpark of 40 nm. Also, surface area measurements done by a Pb underpotential deposition assay suggested a surface enhancement ratio nearly five times higher than that of flat Ag. Furthermore, various de-alloying potentials were assessed to determine the optimal de-alloying potential for the best outcome of the de-alloying process.

Mo-Re-W alloys for high temperature applications: Phase stability, elasticity, and thermal property insights via multi-cell Monte Carlo and machine learning

The increasing demand for materials capable of withstanding high temperatures and harsh environments necessitates the discovery of advanced alloys. This study introduces a computational routine to predict solid-state phase stability and calculates elastic constants to determine high temperature viability. With it, machine learning models were trained on 1,014 Mo-Re-W structures to enable a large compilation of elastic and thermal properties over the complete Mo-Re-W compositional domain with extreme resolution. A series of heat maps spanning the full compositional domain were generated to visually present the impact of alloy constituents on the alloy properties. Our findings identified a balanced (Mo,W) + Re blend as a promising composition for high temperature applications, attributed to a strong and stable (Mo,W) matrix with high Re content and the formation of strengthening (W,Re) precipitates that enhanced mechanical performance at 1600 oC. Several Mo-Re-W compositions were manufactured to experimentally validate the computational predictions. This approach provides an efficient and system-agnostic pathway for designing and optimizing alloys for high-temperature applications.

Fully Consolidated Deposits from Oxide Dispersion Strengthened and Silicon Steel Powders via Friction Surfacing

Abstract The objective of this work is to study the ability of friction surfacing to deposit metal alloys that are difficult to process with traditional methods. Creep and neutron irradiation resistant oxide dispersion strengthened (ODS) materials cannot be produced via conventional casting route due to insolubility of the oxidic and metallic alloy constituents, causing unintended inhomogeneous oxide dispersion and material behavior. Increasing silicon content of Iron-Silicon (Fe-Si) improves electromagnetic properties but embrittles the material significantly and the fusion based manufacturing methods unable to process this steel. The solid-state nature of the friction surfacing process offers a potential alternative processing route to enable wider usage of difficult to process alloy systems. Both ODS and Fe-Si materials are available in powder forms. While the existing literature in friction surfacing focuses on depositing composites by incorporating small quantities powders through holes in consumable rod, this is a first study that shows a large charge of powder can be converted to a homogeneous fully consolidated deposit in friction surfacing. A novel methodology is used that incorporates the high portion of powder feedstock into hollow consumable friction surfacing rods (up to 35% volume fraction). It was found that fully consolidated deposits can be produced with powder feedstocks using proposed methodology. A recrystallized, homogeneous, equiaxed microstructure was observed in Fe-Si 6.8 wt% and a new generation FeAlOY ODS alloy deposits processed with hollow stainless-steel friction surfacing rods. Both powder and rod material plasticize and deposit without bulk intermixing.

Fabrication of three-dimensional bicontinuous porous aluminum by vapor phase dealloying

The development of lightweight, high-specific-surface-area, and exceptionally tough porous aluminum (Al) through dealloying has been consistently captured the attention of the porous metal field. However, widely employed dealloying approaches such as electrochemical dealloying (ECD) and liquid metal dealloying (LMD) face limitations in constructing porous metals with high chemical reactivities. In this study, we employed an emerging vapor phase dealloying (VPD) method, utilizing the differences in saturated vapor pressures among alloy constituents to selectively remove elements with high vapor pressures under optimized temperature and vacuum conditions. The VPD process, characterized by its chemical-free nature and the application of high temperatures, rapidly produces porous Al with varying ligament sizes from the MgZnAl system. The resulting porous Al, distinguished by its crack-free structure and substantial ligament size, exhibits remarkable toughness. The successful fabrication of porous Al using the VPD method effectively bridges the existing gap in generating porous metals with low melting points and high chemical reactivity through ECD and LMD methods. This advancement holds significance for broadening the range of systems and application fields for porous metals.

Copper permalloys for fluxgate magnetometer sensors

Abstract. Fluxgate magnetometers are commonly used to provide high-fidelity vector magnetic field measurements. The magnetic noise of the measurement is typically dominated by that intrinsic to a ferromagnetic core used to modulate (gate) the local field as part of the fluxgate sensing mechanism. A polycrystalline molybdenum–nickel–iron alloy (6.0–81.3 Mo permalloy) has been used in fluxgates since the 1970s for its low magnetic noise. Guided by previous investigations of high-permeability copper–nickel–iron alloys, we investigate alternative materials for fluxgate sensing by examining the magnetic properties and fluxgate performance of that permalloy regime in the range 28 %–45 % Cu by weight. Optimizing the alloy constituents within this regime enables us to create fluxgate cores with both lower noise and lower power consumption than equivalent cores based on the traditional molybdenum alloy. Racetrack geometry cores using six layers of ∼30 mm long foil washers consistently yield magnetic noise around 4–5 pT/Hz at 1 Hz and 6–7 pT/Hz at 0.1 Hz, meeting the 2012 1 s INTERMAGNET standard of less than 10 pT/Hz noise at 0.1 Hz.

Exploring Elemental Powder Approach for Making Al and Ti Containing High-Entropy Alloys by Powder Bed Fusion

This research aimed to produce high-entropy alloys (HEA), namely Mn–Fe–Co–Ni + 5Al and Mn–Fe–Co–Ni + 5Al + 5Ti, through the Powder Bed Fusion technique using elemental powders. Alloy composition has been selected to achieve a HEA matrix with strengthening intermetallic precipitates. Thermo-Calc software has been used to predict solidification behavior and phase stability for non-equilibrium conditions. The experiment involved the execution of an additive manufacturing process with a laser working in point-by-point exposure mode to produce samples using varying laser power and exposure time. The samples underwent investigation via macroscopic examination, porosity analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and hardness testing. Results have shown that processing parameters and alloy constituents directly influenced processability and sample traits. What is more, a high-energy laser beam introduction to the material during the process has helped mitigate the formation of large Ti or Al oxides. In addition, EDS analysis indicated that higher Volumetric Energy Density values enhanced the uniformity of chemical composition, indicating that homogeneity can be achieved by selecting appropriate melting parameters. The results clearly show that these alloys can be successfully (by means of porosity and homogeneity) manufactured from elemental powders via the powder bed fusion technique.

Properties of radiation-induced point defects in austenitic steels: a molecular dynamics study

Austenitic steels are recognized as excellent structural materials for pressurized water reactors due to their outstanding mechanical properties and radiation resistance. However, compared to the widely studied FeCrNi series of steels, little is known about the radiation resistance of FeCrNiMn steel. In this study, the generation and evolution of radiation-induced defects in FeCrNiMn steel were investigated by molecular dynamics simulations. The results showed that more defect atoms were produced in the thermal spike stage, but fewer defects survived at the end of the cascades in FeCrNiMn compared to pure Fe. Point defect properties were analyzed by molecular statics, and the formation energies of defects in FeCrNiMn were lower than those of pure Fe, while the migration energies were higher. Compared to FeCrNi, FeCrNiMn had smaller migration energies and a larger overlap of vacancy and interstitial migration energies. The low vacancy formation energies and widely overlapping migration energies suggested that the number of point defects in the thermal spike stage was higher, but the possibility of recombination was greater. Additionally, Mn exhibited the smallest interstitial formation energies and migration energies. The difference in defect migration energies revealed that vacancy and interstitial defects migrate through different alloy constituent elements. This study revealed the underlying mechanism for the excellent irradiation resistance of FeCrNiMn.

Optimizing Structural and Mechanical Properties of an Industrial Ti-6246 Alloy below β-Transus Transition Temperature through Thermomechanical Processing.

This study aims to investigate the effect of hot deformation on commercially available Ti-6246 alloy below its β-transus transition temperature at 900 °C, knowing that the α → β transition temperature of Ti-6246 alloy is about 935 °C. The study systematically applies a thermomechanical processing cycle, including hot rolling at 900 °C and solution and ageing treatments at various temperatures, to investigate microstructural and mechanical alterations. The solution treatments are performed at temperatures of 800 °C, 900 °C and 1000 °C, i.e., below and above the β-transus transition temperature, for 9 min, followed by oil quenching. The ageing treatment is performed at 600 °C for 6 h, followed by air quenching. Employing various techniques, such as X-ray diffraction, scanning electron microscopy, optical microscopy, tensile strength and microhardness testing, the research identifies crucial changes in the alloy's constituent phases and morphology during thermomechanical processing. In solution treatment conditions, it was found that at temperatures of 800 °C and 900 °C, the α'-Ti martensite phase was generated in the primary α-Ti phase according to Burger's relation, but the recrystallization process was preferred at a temperature of 900 °C, while at a temperature of 1000 °C, the α″-Ti martensite phase was generated in the primary β-Ti phase according to Burger's relation. The ageing treatment conditions cause the α'-Ti/α″-Ti martensite phases to revert to their α-Ti/β-Ti primary phases. The mechanical properties, in terms of strength and ductility, underwent an important beneficial evolution when applying solution treatment, followed by ageing treatment, which provided an optimal mixture of strength and ductility. This paper provides engineers with the opportunity to understand the mechanical performance of Ti-6246 alloy under applied stresses and to improve its applications by designing highly efficient components, particularly military engine components, ultimately contributing to advances in technology and materials science.

Ni‐Alloyed Copper Iodide Thin Films: Microstructural Features and Functional Performance

To tailor electrical properties of often degenerate pristine CuI, Ni is introduced as alloy constituent. Cosputtering in a reactive, but also in an inert atmosphere as well as pulsed laser deposition (PLD), is used to grow thin films. The Ni content within the alloy thin films is systematically varied for different growth techniques and growth conditions. A solubility limit is evidenced by an additional phase for Ni contents , observed in X‐Ray diffraction and atomic force microscopy by a change in surface morphology. Furthermore, metallic, nanoscaled nickel clusters, revealed by X‐Ray photoelectron spectroscopy and high‐resolution transmission electron microscopy (HRTEM), underpin a solubility limit of Ni in CuI. Although no reduction of charge carrier density is observed with increasing Ni content, a dilute magnetic behavior of the thin films is observed in vibrating sample magnetometry. Further, independent of the deposition technique, unique multilayer features are observed in HRTEM measurements for thin films of a cation composition of . Opposite to previous claims, no transition to n‐type behavior was observed, which was also confirmed by density functional theory calculations of the alloy system.

A Study On Stress Management Among Employees Towards Alloy Industries With Reference To Coimbatore

In order to boost strength or corrosion resistance, two or more metallic components are mixed to form an alloy, which is a type of metal. A metallic material composed of two or more elements is called an alloy, sometimes known as a compound or a solution. Although the non-metal carbon is an essential part of steel, the constituents of alloys are normally metals. Alloys are often created by melting the mixture of components. According to customer specifications and drawings, Alloys Industries manufactures and exports a variety of machined and un-machined castings made of Carbon Steel, Stainless Steel, Low Alloy Steel, Heat Resistant Steel, Martensitic Stainless Steel (CA6NM), Precipitated Hardened Steel (CB7Cu-1), Nickel Alloy, and Duplex Stainless Steel. The phrase "stress managements" is broad and includes training, facilitation, and education about the effects that stress has on an individual or group. The study of stress management fosters and encourages the development of coping mechanisms. Employees' physiology and psyche are stressed out by organisational elements such management-labor relations, working conditions, resource distribution, the role of trade unions, employee behaviours, etc. The working practises and policies of an organisation are among its most important influencing variables. This study examined the occupational stress experienced by Alloy Industries in Coimbatore, employees in great detail.

Assessment on structural integrity of aluminium alloy AA6061 water tank used in satellite launch vehicles

AA 6061 is an age-hardenable aluminium alloy with 1wt% magnesium and 0.6wt% silicon as major alloying constituents and is used for manufacture of toroidal water tanks of earth storable liquid rocket engines of ISRO’s launch vehicles. These water tanks are used for storing water to generate steam in gas generator as well as for cooling various components of liquid rocket engine. As a part of the developmental efforts of a new source for fabrication of water tanks, a qualification test procedure was laid down, wherein a quarter portion of the water tank, namely the test article, is designed, fabricated and subjected to series of acceptance and qualification tests, including proof pressure test, cyclic pressure tests with intermediate non-destructive tests. These were finally followed by burst testing of the test article for conforming structural design margins and quality standards adopted for realizing the hardware. A burst test is a destructive test, performed to determine the overload capacity of the pressure vessels depicting margin of safety with respect to its mechanical strength limit. This work highlights the detailed manufacturing processes viz. forming, machining and welding including heat treatment of shells, metallurgical analysis carried out on the parent and weld specimens as well as results from proof pressure and pressure cyclic tests. Further, fractographic studies were carried out on the burst tested hardware, wherein specimens collected from different locations of the burst tested hardware were analyzed using optical scanning electron microscopy, to locate the origin of crack initiation and nature of the failure.

Unconventional Synthesis of Metal (Ni, Co, Ag) Antimony Alloy Particles.

Bimetallic alloy materials attract interest owing to their properties and stability compared to pure metals, especially alloys with nanoscale dimensions. Metal antimony (MSb) alloys, specifically NiSb, are widely used for charge storage applications due to their high stability. Most synthetic approaches to form these materials require drastic conditions (e.g., high temperatures, potent reducing agents, and extended reaction times), limiting control over the final morphology. The other viable approach is a galvanic replacement that uses unstable materials as precursors. In this work, we present a new and facile method to prepare several MSb (M = Ni, Co, Ag) alloys with shape control by reacting Sb2S3 particles with a metal(M)-sulfide single source precursor in trioctylphosphine (TOP) under mild conditions. Furthermore, we explore the role of TOP as a reducing agent and demonstrate how both alloy constituents are crucial for mutual stabilization. Electrochemical studies are also performed on these NiSb particles, showing their ambipolar nature and allowing their utilization as the active ingredient in the demonstrated high-energy-density symmetric supercapacitor.

Development of CoCr0.65FeNi-BSiC as a self-fluxing high-entropy alloy for thermal spraying

Self-fluxing alloys are used as thermal spray coatings for superimposed tribological and corrosive stresses. Subsequent fusing of self-fluxing alloy coatings forms a gas- and liquid-tight and strongly adherent coating. These alloys have been generally composed of one property defining main element and minor alloying elements such as Cr, Si, B and C. However, high-entropy alloys (HEAs) promise a significant improvement of the coating properties by solid solution strengthening and allow fulfilling increased application requirements. The current study focuses on the development of a self-fluxing HEA for thermal spraying using a novel CoCr0.65FeNi matrix with the alloy constituents B, Si and C. The CoCr0.65FeNi-BSiC powder was produced by gas atomization. Bulk material was produced in an arc furnace and by spark plasma sintering as a reference condition. The coatings were deposited using powder flame spraying. After fusing, the coating exhibits a closed porosity and good metallurgical bonding. The microstructure, phase formation, and wear behavior of the thermally sprayed CoCr0.65FeNi-BSiC self-fluxing HEA system in conjunction with the commercially available alloy Ni600 were analyzed. The fused CoCr0.65FeNi-BSiC coating exhibited a similarly high sliding wear resistance as the fused Ni600 coating. The high wear resistance and formation of a dense coating confirm the potential of this new development approach.

Differences in Oxidation Behavior of Conventionally Cast and Additively Manufactured Co-Base Alloy MAR-M-509

AbstractHigh-temperature oxidation behavior of conventionally cast and additively manufactured (AM) Co-base alloy MAR-M-509 was compared in the present study. The specimens were exposed in air at 1000 °C and characterized by means of scanning electron microscopy equipped with energy/wavelength dispersive x-ray spectroscopy (EDX/WDX) and electron backscatter diffraction as well as transmission electron microscopy. Substantial differences in the oxidation processes of two alloy versions were observed. Faster oxidation of the cast alloy was mainly induced by (1) oxidation of coarse primary carbides, (2) internal oxidation and nitridation processes and (3) incorporation of other alloy constituents (e.g., Co, Ni, W) into the Cr-oxide scale. AM specimens, in contrast, formed a more homogeneous, thinner and better adherent external oxide scale. The results are discussed in terms of differences in the chemical composition and alloy microstructure, including the grain size distribution in the material and the morphology of the strengthening precipitate phases.

Microstructure and properties study of Mg2-xYxNi0.9Co0.1 (x = 0, 0.1, 0.2, 0.3) hydrogen storage alloys

To enhance the hydrogen storage performance of Mg-Ni system alloys, multi-elemental alloys incorporating Y element, namely Mg2-xYxNi0.9Co0.1 (x = 0, 0.1, 0.2, 0.3), were synthesized through ball milling and sintering. The microstructures of Mg2-xYxNi0.9Co0.1 (x = 0, 0.1, 0.2, 0.3) alloys were characterized using XRD and SEM/EDS techniques, and the hydrogen storage properties of Mg2Ni0.9Co0.1 and Mg1.7Y0.3Ni0.9Co0.1 alloys were evaluated via the Sieverts method. At a sintering temperature of 500 °C, the Y element existed in the form of Y/Y2O3 phases and displayed no reactivity with other alloy constituents. The addition of Y enhanced the activation performance of Mg-Ni system alloys, because it takes 2 times for Mg1.7Y0.3Ni0.9Co0.1 alloy to complete activation, while Mg2Ni0.9Co0.1 needs 3, albeit causing a slight reduction from 3.6 wt% to 3.2 wt% in the hydrogen storage capacity when Y replaced Mg. The enthalpy of hydrogen desorption of Mg1.7Y0.3Ni0.9Co0.1 alloy was 57.4 kJ mol−1 H2, which was significantly lower than that of Mg2Ni0.9Co0.1 (68.0 kJ mol−1 H2) and Mg2Ni alloy (64.4 kJ mol−1 H2), indicating improved thermodynamic properties. Moreover, the apparent activation energy of Mg2Ni0.9Co0.1 (71.48 kJ mol−1 H2) was lower than that of Mg1.7Y0.3Ni0.9Co0.1 (83.62 kJ mol−1 H2), implying that the addition of Y reduced the kinetic properties.

Experimental study on phase relations in the Al-Mo-Nb ternary system

Aluminium alloying can improve the anti-oxidation property of the Nb/Mo-Si-based superalloy. Therefore, the Al-Mo-Nb ternary system is one of the important subsystems of the Al-alloyed multi-component system. The isothermal sections at 1200 and 1000 ℃ and the liquidus projection of the Al-Mo-Nb system were studied experimentally. The phase structures and the phase constituents of the as-cast alloys and the annealed alloys were analyzed and measured using X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) as well as electron probe micro-analysis (EPMA) techniques. Five three-phase regions and eleven two-phase regions in isothermal section at 1000 °C and six three-phase regions and twelve two-phase regions in isothermal section at 1200 °C were determined, and no ternary compound was observed. Fourteen primary solidification regions and eleven invariant reactions were deduced based on the study on the solidification processes of the as-cast alloys. The present experimental results can be used for the future thermodynamic assessment of the Al-Mo-Nb ternary system, and be helpful for the database development of the multi-components Nb/Mo-Si-based superalloy system.

Development of Zn–Mg–Ca Biodegradable Dual-Phase Alloys

In this paper, in order to achieve the development of a novel biodegradable dual-phase alloy in a Ca–Mg–Zn system, the establishment of the control strategy of degradation behavior of alloys composed of two phases was attempted by the control of alloy composition, constituent phases, and microstructure. By combining two phases with different dissolution behavior, biodegradable alloys are expected to exhibit multiple functions. For example, combining a suitable slow dissolving phase with a faster dissolving second phase may allow for dynamical concavities formation during immersion on the surface of the alloy, assisting the invasion and establishment of bone cells. Without the careful control of the microstructure, however, there is a risk that such dual-phase alloy rapidly collapses before the healing of the affected area. In this study, ten two-phase alloys consisting of various different phases were prepared and their degradation behaviors were examined. Consequently, it was found that by combining the IM3 and IM1 intermetallic phases with the compositions of Ca2Mg5Zn13 and Ca3Mg4.6Zn10.4, the expected degradation behavior can be obtained.