Metallurgical Studies Research Articles

DEVELOPING A NUMERICAL MODEL TO OPTIMISE THE LASER-BEAM-WELDING PARAMETERS FOR JOINING TITANIUM TUBES

In this work Nd:YAG laser beam welding (LBW), which requires a low heat input, was applied to join grade-2 titanium tubes. The pulse duration and pulse energy were varied according to a two-factor three-level central composite face-centred (CCFC) design to join grade-2 titanium tubes. A numerical model was developed to correlate LBW process parameters and ultimate tensile strength (UTS). Validation of the developed model was done using the analysis of variance. Pulse duration has a more significant impact compared to pulse energy. The highest and lowest values of each process parameter produced a weak UTS, which was less than 338 MPa. The change in the UTS for each process parameter was analysed with metallurgical studies of the joints. Optimised process parameters for improved UTS were identified and reported.

Wire arc direct energy deposited multiphase steel through in situ micropowder alloying: mechanical and metallurgical studies

Purpose This study aims to investigate the effect of copper and titanium micropowder addition on the mechanical and metallurgical properties of additively manufactured low-carbon steel, aiming to produce a modified (multiphase) steel with ferritic low-carbon steel using in situ micropowder addition during wire arc direct energy deposition (WA-DED). Design/methodology/approach A robotic arm equipped with a GMA welding source deposited ER70S6 filler wire on AISI S235 substrate steel using WA-DED. Cu and Ti micropowders were interspersed between layers for microstructural modifications. Microscopy, spectroscopy, diffraction and mechanical testing were used to evaluate the properties of the deposited samples. Findings Incorporating Cu and Ti micropowders significantly enhanced the yield and tensile strength of the deposited material, showing an 83% increase in yield strength and a 33% increase in tensile strength. Microstructural analysis identified key phases such as ferrite, pearlite, bainite, retained austenite and martensite/austenite, with Cu and Ti acting as grain refiners. Nanoscaled Cu precipitates contribute to enhanced low-temperature toughness and a 150% improvement in impact strength at −30°C. Originality/value This study presents a novel approach to overcome the limitations of the available alloys (filler materials). This can be achieved by introducing in situ micropowder alloying during the WA-DED process. The micropowder addition allows altering the properties of the deposited material without changing the parent filler material itself, achieving the desired composition. With this approach, there is no need to manufacture the filler material with the preferred alloy composition separately and then carry out the deposition process.

A Metallurgical Study of Micro Plasma Arc Welded Joint of Austenitic Stainless-steel Blank

A Metallurgical Study of Micro Plasma Arc Welded Joint of Austenitic Stainless-steel Blank

Metallurgical study of manganese lump ores from Minas Gerais, Brazil

Metallurgical study of manganese lump ores from Minas Gerais, Brazil

Microstructure and mechanical assessment of Inconel 625 and AISI 904L dissimilar joints using high-density welding technique for pressure vessels

The dissimilar bimetallic joints of 5 mm thick Inconel 625 and AISI 904L were accomplished through the high-density fiber laser welding (LBW) process. The metallurgical investigation ensured the micro-segregation of Mo and Nb in the dendritic and inter-dendritic regions along with the formation of secondary topologically closed packed (TCP) phases. In addition to the metallurgical studies the Kernal average misorientation (KAM), Schmid factor (SF), and nucleation of the new grains were investigated through Electron backscattered diffraction (EBSD) analysis. The tensile strength opined the occurrence of failure on the 904L side, away from the weld seam ensuring that the joints have a higher strength. The notch tensile showed a higher strength of 678 ± 4 MPa in the weld zone than that of the 904L base alloy. The Charpy V notch studies showed a drastic decrease in the impact toughness with 38 ± 2 J as compared to the base alloys under sudden impact loading at room temperature (RT).

Metallurgical and mechanical study of T6 heat-treated SiC particle-reinforced A356-aluminium matrix composite

Metallurgical and mechanical study of T6 heat-treated SiC particle-reinforced A356-aluminium matrix composite

Mechanical properties of CO2 laser beam butt-welded plates of Hastelloy c-276

In the current investigation, thermo-mechanical analysis is carried out for Hastelloy C-276 using laser beam welded butt joints. The Gaussian heat source model is used for transient thermal analysis, and the maximum temperature at the weld area resulted in residual stresses within safe limits. To validate, the experimentation was carried out with CO2 Laser beam welding using an L4 orthogonal array. Sample 2 had the least-residual stresses in the weldment, and the mechanical and metallurgical properties studies were carried out. The residual stress distribution was measured using X-ray diffraction and was acceptable within the yield limits of the material. Finite Element Analysis (FEA) and experimental residual stresses were compared; the FOS was 2.088, and the remaining samples were more than 2.0 compared to the base material tensile strength. Tensile tests confirmed that the strength of the weld zone is higher than that of the parent metals.

Process intensification of metal solvent extraction studies using a miniaturized solvent extraction plant

This study examines the potential of a miniaturized solvent extraction plant (MSXP) to improve the efficiency and reproducibility of laboratory and pilot-scale metallurgical studies that typically require extended testing periods. The MSXP has been designed to replace conventional solvent extraction (SX) apparatus and aims to reduce start-up time, time to reach equilibrium, and overall test time. Two copper solvent extraction (Cu-SX) research campaigns were conducted to test the functionality, ease of operation, modularity, and reproducibility of the MSXP. The first campaign quantified the extraction efficiency and net copper transfer, while the second campaign operated the MSXP in a semicontinuous countercurrent flow configuration with three extraction and two stripping stages. The main variables studied in the first campaign are the number of stages (1-3), volumetric flow rates (O/A, 1-3), and organic phase residence time in the micro-contactor (0.7-2.4 min). The results demonstrate that the MSXP can work with very low stage efficiencies (48%), while achieving high copper recoveries (> 90%). At the stripping circuit level, we show that the MSXP can operate at superior stage efficiencies (> 100%), with low copper recoveries (30%–55%). The reproducibility evaluation also demonstrates high statistical confidence (< 6% CV) in the obtained process values. The MSXP offers great flexibility in net copper transfer and can be used to benchmark and emulate a wide range of Cu-SX systems. Experimental Cu-SX campaigns can be run in about 60 min while investing roughly US$1.4/h on reagents, which is significantly lower compared to typical campaigns that can last from days to weeks to reach reliable research outcomes and require about US$62/h for reagents. The potential of MSXP extends to more elaborate solvent extraction systems, specifically those designed to purify energy-critical elements like lithium, nickel, cobalt, or rare-earth elements. This study demonstrates the promise of process intensification approaches for improving the efficiency of laboratory and pilot-scale SX studies, which can help in reducing time, reagents, and energy consumption while improving the reproducibility of results.

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.

Regional characteristics of iron manufacturing techniques and the related issue of the supply system on Han’s southern Frontiers: A metallurgical study of iron implements from Chenzhou, Hunan

Southern Hunan is known to be one of the few iron manufacturing regions in the Han period. The study of iron implements from this region should yield important evidence concerning the regional iron-making techniques used and the local iron industry. We provide a detailed account of the technological aspects of iron implements yielded from Chenzhou, a major node on the traffic routes entering the broader southern frontiers. Our analysis focuses on the metallographic features and chemical compositions of inclusions in the examined objects. The results reveal that cast iron and related annealing or decarburization techniques were commonly used. Most implements were made using solid-state decarburization of cast iron, along with malleable cast iron and fined iron. This technological profile is similar to other case studies in the literature, but also highlights regional characteristics such as the relatively sparse presence of fined iron. Based on this observation, we discuss various factors that could have contributed to this situation. In a broader context, the analysis of this collection can contribute to the further investigation of the regional characteristics of the Han period iron industry.

Metallurgical and mechanical study of the effect of FSW parameters on dissimilar joining of St37 and AZ31

Metallurgical and mechanical study of the effect of FSW parameters on dissimilar joining of St37 and AZ31

Advances in Analytical Techniques and Applications in Exploration, Mining, Extraction, and Metallurgical Studies of Rare Earth Elements

The use of analytical techniques is important and critical in all areas related to REE, such as basic fundamental research, exploration, mining, extraction, and metallurgical activities at different stages by different industries. At every stage of these activities, rock, ore, minerals, and other related materials have to be analyzed for their REE contents in terms of elemental, isotopic, and mineralogical concentrations using different analytical techniques. Spectacular developments have taken place in the area of analytical instrumentation during the last four decades, with some of them having shrunk in size and become handheld. Among laboratory-based techniques, F-AAS, GF-AAS, ICP-OES, and MP-AES have become very popular. Because of high sensitivity, fewer interference effects, and ease of use, ICP-MS techniques, such as quadrupole ICP-MS, ICP-MS/MS, ICP-TOF-MS, MH-ICP-MS, HR-ICP-MS, and MC-ICP-MS, with both solution nebulization as well as direct solid analysis using laser ablation sample introduction methods, have become more popular for REE analysis. For direct analysis of solids, INAA, XRF, and LIBS techniques, as well as LA-based ICP-MS techniques, are being extensively utilized. The LIBS technique in particular requires little to no sample preparation. TIMS, SIMS, and SHRIMP techniques are being used for isotopic as well as dating REE depots. Portable analytical techniques, such as pXRF, pLIBS, and Raman spectrometers are able to perform in situ analysis even in the field, helping to make fast decisions during exploration studies. At present, hyperspectral remote sensing techniques including handheld, drone, and satellite-based techniques have become very popular in REE exploration studies because of their ability to cover larger areas in a limited time and, thus, became very cost-effective. Deployment of microanalytical devices/sensors mounted in remotely operated vehicles (ROV) is being successfully utilized in detecting REE-rich deposits in the deep oceans. Providing updated in-depth information on all these important aspects with suitable examples, especially from the point of view of REE research studies is the focal point of this review article.

Experimental investigations on surface morphology and metallurgical studies of additive manufactured stainless steel features finished by electrolytic ionic interactions

The laser powder bed fusion (LPBF) technique is used for fabricating complex features compared to traditional manufacturing processes. Besides several advantages, LPBF features have high surface roughness, which necessitates finishing processes. The electrochemical finishing process is widely used for reducing surface roughness using electrolytic ionic interactions. This reduction can be affected by several parameters in the experimental work. However, the most significant parameters (voltage, finishing time, and temperature) were chosen for the one-factor-at-a-time technique and optimized by central composite rotatable design (CCRD) to investigate the surface roughness reduction. The surface roughness model was validated by performing a confirmation test at optimized process parameters and achieved the optimal Ra of 0.245 µm from the initial Ra of 11.763 µm.

Advancement of extreme environment additively manufactured alloys for next generation space propulsion applications

The National Aeronautics and Space Administration (NASA) has been involved in the development and maturation of metal additive manufacturing (AM) for space applications since the late 2000's. Several efforts have focused on the understanding of AM processes through material characterization and testing, standards development, component fabrication, and infusion into propulsion development and flight applications. NASA matured commonly used aerospace alloys from various alloy families (Nickel, Copper, Stainless and Steel, Aluminum, and Titanium-based) through detailed AM process and heat treatment characterization, in addition to mechanical and thermophysical testing. While these alloys are actively used in many propulsion applications, there is a need for ongoing AM optimized alloys using integrated computational materials engineering (ICME) and process development for high performance applications. The applications targeted are liquid rocket engines; advanced propulsion systems; and in-space propulsion with high heat fluxes, high pressure, and/or that use propellants that can degrade alloys (e.g., hydrogen). This paper highlights the characterization and physical properties of the more common AM alloys using laser powder bed fusion (L-PBF) and laser powder directed energy deposition (LP-DED) processes. Additionally, this paper discusses some of the ongoing novel alloy development and maturation using AM for use in these harsh environments, such as GRCop-42, GRCop-84, NASA HR-1, GRX-810, and C-103. The results from these processes demonstrated that AM could enable rapid development, and that optimized alloys could be developed using ICME, yielding higher performances. These alloys have undergone modeling, fundamental metallurgical evaluations, heat treatment studies, detailed microstructure characterization, and mechanical testing campaigns. This, combined with direct application-specific component fabrication and hot-fire testing, enabled the increase of the Technology Readiness Level (TRL) through high duty-cycle testing. A background and overview of these novel AM-enabled alloys and AM processing developments including metallurgical and mechanical property studies is presented here. The latest advancement in the parallel component development and hot-fire testing and future developments for these alloys is also discussed.

Metallurgical, erosion, and sensitization performance of TiAlN monolayer and TiAlN/TiN multilayer ceramic coatings on AISI 304 boiler steel

In the present work, TiAlN monolayer and TiAlN/TiN multilayer ceramic coatings were deposited on AISI 304 austenitic stainless steel by plasma arc physical vapor deposition (PAPVD) process. The metallurgical, erosion, and sensitization performance of these coatings were compared with uncoated 304 boiler steel. Metallurgical studies depicted formation of Al and Ti nitrides on monolayer and multilayer coated steel surfaces, which resulted into higher nitriding at the surface and dense coating formation on boiler steel substrate. Multilayer film exhibited comparatively lesser porosity, lower surface roughness, and higher hardness than monolayer coated and uncoated steel. The erosion performance was evaluated at 30° and 90° besides 2 g/min and 3 g/min flow rates of Al2O3 erodent material for coated and uncoated steel substrate. Multilayer coated 304 steel possessed lower erosion wear rate as evaluated through lesser weight loss before and after erosive wear, smaller crater formation, and minimal adherence of erodent material along with lesser Fe content on eroded surface relative to monolayer coated and uncoated steel. Multilayer coated steel thermally aged at 750° for 24 h had least degree of sensitization (DOS) compared to monolayer coated and uncoated aged boiler steel. Although monolayer coated steel performed better than uncoated one in erosion and sensitization performance but multilayer coating performance was best among all coated and uncoated steel used for present study. Thus, it was established that TiAlN/TiN multilayer coating on AISI 304 boiler steel has improved its metallurgical, erosion, and sensitization performance.

Investigation on post processing techniques oriented towards strength improvement of 3D printed SS316L

Additive manufacturing has its roots in all manufacturing sectors, right from conventional lathe tool to nose plate of rockets. Additive manufactured components provide better strength than cast products but have lower strength than forged components. 3D printed components always require post processing to improve the strength. Strength can be enhanced by heating, followed by modified cooling techniques. At some points, electron beam and laser source increase the strength of the component. Shot blasting and shot peening improve the fatigue life of the component. This study focuses on the post processing of 3D printed Stainless Steel (SS) 316L material. Various parameters involved in 3D printing of SS316L have an influence on the final product. SS316L material finds its application in automotive and aerospace industries with different property requirements. Subsequent to 3D printing, post processing is also very important to meet the required mechanical and physical properties. Post processing includes laser peening technique to improve the strength as observed during mechanical testing that includes hardness and residual stresses analysis. Metallurgical study that includes microscopy, FESEM with EDS mapping shows the change in microstructural arrangement which contributes to the improvement in strength. Surface profile as observed in the final product, has higher value compared to that of the as-built specimens.

Investigation of micro structural and mechanical properties of friction surfacing on low carbon steel by using stainless steel grades

Friction coating is an advanced manufacturing process that has been developed and successfully marketed over the past decade. This process is used to prevent and resist corrosion in coatings and to regenerate worn structural elements. Currently, process parameters for producing new materials or substrate geometries are selected through experimentation, requiring long-term development work. The effect of transverse velocity on coating geometry, interfacial bonding properties, and mechanical properties is investigated. We changed the lateral speed, and the rotational speed and determined the axial load. Metallurgical studies were performed by light microscopy, scanning electron microscopy (SEM), and mechanical tests including bending and micro testing. The coatings are formed by cracks and have a fully austenitic structure. Speed is affected by bond integrity and film thickness. A solid metallurgical interface with 100% bond integrity has been developed for advanced food coatings. The higher the transverse speed, the thinner the layer, and the higher the bond strength.

Pseudo-random time modulation technique for neutron diffraction instruments on compact accelerator-driven neutron sources

Time modulation methods are routinely used on neutron scattering time-of-flight instruments, which exploit the time structure of neutron pulses for energy determination. In the past, complex time modulation methods were proposed, either to maximize the neutron flux which can be used, or to increase the energy resolution of the measurements. In this article, we explore the possibilities offered by such methods and in particular random modulation using statistical choppers to improve the performances of the DIoGENE scattering instrument installed around the IPHI-neutron CANS source at Saclay. We conclude that when the source is operated in continuous mode, the implementation of a statistical chopper is very efficient to perform either metallurgical studies such as strain scanning or phase transition studies. Random modulation techniques may be easily and efficiently implemented because the high capacity of modern computers enables high-speed data processing from large surface pixelated detectors.

Effect of different volume ratios of SiC and TiO2 reinforcement particles on mono and hybrid surface composites of AA7075-T651 through friction stir processing

In the present work, the different volume ratios of silicon carbide and titanium dioxide particles were incorporated with AA7075-T651 to improve the surface properties using multipass friction stir processing. The metallurgical study of the friction stir processed samples was examined through optical microscopy and field emission scanning electron microscopy with energy-dispersive X-ray analysis. In addition, the microhardness, wear, and corrosion properties were measured and analyzed. The results revealed that the increased amount of SiC particles caused uniform particle dispersion and was devoid of cluster-rich regions within the matrix. The increased volume of SiC particles exhibited a smaller grain size due to higher grain refinement. The sample with 100% SiC showed superior mechanical, tribological, and corrosion properties. The microhardness of sample with 100% SiC was increased by 13.60% compared to base metal, it was also better compared to other composite samples. Similarly, the coefficient of friction, wear rate, and corrosion resistance properties were reduced by 43.24%, 14.98%, and 75%, respectively.

Effect of variation of WC reinforcement on metallurgical and cavitation erosion behavior of microwave processed NiCrSiC-WC composites clads

Components operating in fluid handling systems most frequently experience cavitation erosion. The coatings/claddings fabricated by microwave irradiation method can remarkably improve cavitation erosion. In the present work, WC reinforced NiCrSiC based metal matrix composite clads with varying weight percentage of WC particles were developed on SS 316 steel using microwave heating method. The metallurgical and microstructural study of composite clads were analyzed using SEM/EDS, XRD and porosity, microhardness was also investigated. Cavitation erosion behavior of the claddings were evaluated using vibratory cavitation erosion tester. The failure mechanism due to cavitation erosion was explored using SEM study. The relationship of cavitation erosion behavior with variation in weight percentage (10%, 20%, and 30%) of reinforced particles in the composite clad was also explored. It has been observed that with an increase in the weight percentage of WC particles, the cavitation erosion rates decreased drastically initially (37.9%) and, but later significant change was not observed (4.89%, 2.44%). Eroded surface study revealed that with increase in the weight percentage of WC reinforcement the mode of damage changes from ductile to brittle. Further it was studied that the pits, crater, micro-cracks, and plastic deformation were the primary wear mechanisms.