Metal Dilution Research Articles

Low [O/Fe] Ratio in a Luminous Galaxy at the Early Cosmic Epoch (z > 10): Signature of Short Delay Time or Bright Hypernovae/Pair-instability Supernovae?

Abstract We present an [O/Fe] ratio of a luminous galaxy GN-z11 at z = 10.60 derived with the deep public JWST/NIRSpec data. We fit the medium-resolution grating (G140M, G235M, and G395M) data with the model spectra consisting of BPASS-stellar and Cloudy-nebular spectra in the rest-frame UV wavelength ranges with Fe absorption lines, carefully masking the other emission and absorption lines in the same manner as previous studies conducted for lower-redshift (z ∼ 2–6) galaxies with oxygen abundance measurements. We obtain an Fe-rich abundance ratio [ O / Fe ] = − 0.37 − 0.22 + 0.43 , which is confirmed with the independent deep prism data as well as by the classic 1978 index method. This [O/Fe] measurement is lower than that measured for star-forming galaxies at z ∼ 2–3. Because z = 10.60 is an early epoch after the Big Bang (∼430 Myr) and the first star formation (likely ∼200 Myr), it is difficult to produce Fe by Type Ia supernovae (SNe Ia), which requires sufficient delay time for white-dwarf formation and gas accretion. The Fe-rich abundance ratio in GN-z11 suggests that the delay time is short or that the major Fe enrichment is not accomplished by SNe Ia but by bright hypernovae (BrHNe) and/or pair-instability supernovae (PISNe), where the yield models of BrHNe and PISNe explain Fe, Ne, and O abundance ratios of GN-z11. The [O/Fe] measurement is not too low to rule out the connection between GN-z11 and globular clusters (GCs) previously suggested by the nitrogen abundance but rather supports the connection with a GC population at high [N/O] if a metal dilution process exists.

Mapping radial abundance gradients with Gaia -ESO open clusters. Evidence of recent gas accretion in the Milky Way disk

Recent evidence from spectroscopic surveys points towards the presence of a metal-poor, young stellar population in the low-alpha , chemically thin disk. In this context, the investigation of the spatial distribution and time evolution of precise, unbiased abundances is fundamental to disentangle the scenarios of formation and evolution of the Galaxy. We study the evolution of abundance gradients in the Milky Way by taking advantage of a large sample of open star clusters, which are among the best tracers for this purpose. In particular, we used data from the last release of the Gaia -ESO survey. We performed a careful selection of open cluster member stars, excluding those members that may be affected by biases in spectral analysis. We compared the cleaned open cluster sample with detailed chemical evolution models for the Milky Way, using well-tested stellar yields and prescription for radial migration. We tested different scenarios of Galaxy evolution to explain the data, namely, the two-infall and the three-infall frameworks, which suggest the chemical thin disk is formed by one or two subsequent gas accretion episodes, respectively. With the performed selection in cluster member stars, we still find a metallicity decrease between intermediate-age ($1<$ Age/Gyr $<3$) and young (Age $<1$ Gyr) open clusters. This decrease cannot be explained in the context of the two-infall scenario, even by accounting for the effect of migration and yield prescriptions. The three-infall framework, with its late gas accretion in the last 3 Gyr, is able to explain the low metallic content in young clusters. However, we have invoked a milder metal dilution for this gas infall episode relative to previous findings. To explain the observed low metallic content in young clusters, we propose that a late gas accretion episode triggering a metal dilution would have taken place, extending the framework of the three-infall model for the first time to the entire Galactic disk.

Effect of welding parameters on microstructure and mechanical properties of dissimilar AISI 304/ductile cast iron fusion welded joints

Problems associated with dissimilar fusion welding are mainly originated from the differences in melting points, coefficients of thermal conductivity and thermal expansion, …etc., and carbon content when welding dissimilar ferrous materials. In this study, the problems associated with dissimilar fusion welding of stainless steel AISI304 with ductile cast iron DCI grade A536 were investigated. Using shielded metal arc welding (SMAW) process, various welding parameters were studied to investigate the successful/accepted dissimilar welded joint(s). Welding electrodes and welding techniques were the main studied parameters. Microstructural and mechanical investigations were carried out for welded joints under different welding parameters. Tensile, impact and hardness tests coupled with optical and scanning electron microscopic examinations with EDX analysis were made for metallurgical and mechanical evaluations of welded joints. This extensive study could solve the problem of dissimilar welding between ductile cast iron and 304 stainless steel. The main results showed that joints welded by ENiCrFe-3 electrode in root pass and ENiFe-CI in filling passes were the successful dissimilar welded joints with 422 MPa tensile strength which represents 104% of annealed DCI base metal and without any changes in toughness properties, where toughness at HAZ of DCI was 18 J. High Ni content in weld metal increased the strength, ductility and reduced the weld metal dilution.

Structural Consequences of Different Metal Compositions in the Doped Spin‐Crossover Crystals [FezM1−z(bpp)2][BF4]2 (M = Ni, Zn; bpp = 2,6‐Bis{pyrazol‐1‐yl}pyridine)

Variable temperature crystallographic characterization of [FezZn1‒z(bpp)2][BF4]2 (bpp = 2,6‐bis{pyrazol‐1‐yl}pyridine; z = 0.88, 0.72 and 0.27) and [FezNi1‒z(bpp)2][BF4]2 (z = 0.83, 0.72 and 0.32) is presented. Comparison with previously published data confirms the isothermal unit cell volume change during spin‐crossover (ΔVSCO) behaves differently in the Zn‐ and Ni‐doped crystals. For the FeZn crystals, the relationship between ΔVSCO and z is continuous for z ≥ 0.3 but is steeper than expected, so ΔVSCO ≈ 0 for z = 0.27. In contrast ΔVSCO in the FeNi materials shows only a small variation between 0.83 ≥ z ≥ 0.46, before decreasing more strongly at higher dilution. ΔVSCO in each FeZn crystal is smaller than for its FeNi analogue with a similar composition. As well as the dopant ion ionic radius, the smaller ΔVSCO for the Zn‐doped materials reflects their T½ values, which are lower than for their FeNi counterparts. The contribution of T½ to this behavior is especially evident at high metal dilution.

Metallographic and Extraction Replica Methods for Characterization of Tungsten Heavy Alloy: H13 Clads

Tungsten heavy alloys are used in demanding high pressure die casting applications due to their high temperature strength, high thermal conductivity, and low thermal expansion. High cost limits applications to small sintered die inserts and manual gas tungsten arc weld repairs. A new tungsten heavy alloy consumable, Anviloy wire, was developed for automated cladding of hot work tool steel dies. Literature regarding characterization of tungsten heavy alloy die steel clads was lacking. Understanding base metal dilution effect on clad microstructure is critical but required new sample preparation methods. An Anviloy wire-H13 clad was made using hot wire gas tungsten arc cladding and analyzed with metallography. Samples were found to have grain boundary M6C carbide phase as-welded with the help of an alkaline sodium picrate etchant. An isothermally aged arc crucible melted sample of the same composition was characterized using metallography, scanning electron microscopy, and transmission electron diffraction. The clad representative arc crucible melted sample was subjected to isothermal aging at 725°C for 100 hours. Isothermal aging resulted in precipitation of a high volume fraction of intermetallic platelets. Using a new carbon extraction replica sample preparation method involving two chemical polishing steps, transmission electron diffraction of precipitates indicated they were mu phase intermetallic.

Effect of laser beam wobbling and welding speed in X80 steel wire-fed laser root welds

A wobble laser was combined with a wire feed during laser root welding of X80 pipeline steel. The enlarged laser irradiation area and molten pool resulting from the laser beam wobbling provided a better gap-bridging ability, which is critical during laser welding of thick pipes. Applying laser beam wobbling enabled better control of filler metal dilution, which determined the weld metal microstructure and mechanical properties. In the present work, more bainite along with reduced acicular ferrite was formed in the wobble laser weld, due to the effect of dilution resulting from increased base material melting during wobbling beam, along with an inhomogeneous fusion zone microstructure. The instrumented indentation testing was utilized for the first time to distinguish the local yield strength variation of different regions of the fine weld zones, allowing one to verify if the weld metal strength meet the target value in industrial standards. As the productivity being improved when the welding speed increased from 1.0 to 1.5 m/min, the presence of more low temperature transformation products generated with a faster cooling led to a 26 HV higher hardness and a 70 MPa higher yield strength in the upper region of the fusion zone.

Estimation of solidification cracking susceptibility in Al–Si–Cu alloy weld: effects of anisotropic permeability and deformation orientation

Weld solidification cracking susceptibility (SCS) was evaluated using an analytical model developed considering the anisotropic permeability (i.e., permeability which is different in directions parallel and perpendicular to the primary dendrite arms) and deviation of the imposed deformation from the normal direction with respect to the primary dendrite arm (ϕ). The model was investigated for Al–Si–Cu alloys in the solid fraction range from 0.87 to 0.94. Low Si- high Cu content alloys showed the maximum SCS due to variation in the physical properties of weld pool, i.e., viscosity, solidification range and solid fraction as a function of temperature. Decrease in deviation of the deformation direction (ϕ) led to increase in the SCS. Using the anisotropic permeability as a function of the primary dendrite arm spacing (λ1) led to a change in the peak position of shrinkage pressure depression towards the high Si-high Cu content alloys. Arc oscillation imposed a dual impact on the SCS of weld: (i) increased the SCS by enhancement of the base metal dilution, i.e., adding more Cu into the weld pool and (ii) decreased the SCS by refining the weld microstructure and twisting the grain boundaries which in turn changed the deformation direction on the grain boundaries. Results of the weldability test on Al–Cu sheets welded using Al–Si filler metal were in good agreement with the model prediction.

Electro-Elastic Modeling of Thermal Spin Transition in Diluted Spin-Crossover Single Crystals.

Spin-crossover solids have been studied for many years for their promising applications as optical switches and reversible high-density memories for information storage. This study reports the effect of random metal dilution on the thermal and structural properties of a spin-crossover single crystal. The analysis is performed on a 2D rectangular lattice using an electro-elastic model. The lattice is made of sites that can switch thermally between the low-spin and high-spin states, accompanied by local volume changes. The model is solved by Monte Carlo simulations, running on the spin states and atomic positions of this compressible 2D lattice. A detailed analysis of metal dilution on the magneto-structural properties allows us to address the following issues: (i) at low dilution rates, the transition is of the first order; (ii) increasing the concentration of dopant results in a decrease in cooperativity and leads to gradual transformations above a threshold concentration, while incomplete spin transitions are obtained for big dopant sizes. The effects of the metal dilution on the spatiotemporal aspects of the spin transition along the thermal transition and on the low-temperature relaxation of the photo-induced metastable high-spin states are also studied. Significant changes in the organization of the spin states are observed for the thermal transition, where the single-domain nucleation caused by the long-range elastic interactions is replaced by a multi-droplet nucleation. As to the issue of the relaxation curves: their shape transforms from a sigmoidal shape, characteristic of strong cooperative systems, into stretched exponentials for high dilution rates, which is the signature of a disordered system.

Nanoarchitectonics of CuNi bimetallic nanoparticles in ionic liquids for LED-assisted synergistic CO2 photoreduction

An efficient and robust photocatalysts have been developed by combining bimetallic CuNi nanoparticles and TiO2. Simple co-reduction of CuCl2.2H2O and NiCl2.6H2O in 1-n-butyl-methylimidazolium tetrafluoroborate (BMIm.BF4) ionic liquid affords small sized (4–5 nm) bimetallic CuNi NPs. Low-Energy Ion Scattering (LEIS) and magnetic measurements analyses reveals that the NPs are alloyed nanostructure-having Ni enriched surface. CuNi NPs decorated on P25-TiO2 remarkably promote the generation of CH3OH and syngas as compared to their monometallic counter-parts using 1200 mW LEDs of 450 nm (visible) light irradiations in an optofluidic microreactor. The system continuously produces CH3OH with a rate of 102.1 μm.g−1.h−1 (AQY 0.90%) and syngas (H2 118.8 and CO 24.6 μmol.g−1.h−1), represents a high yield and quantum efficiency. Where as, its counter-part, Ni/TiO2, generate CH3OH with a rate of 37.0 μm.g−1.h−1, H2 200.0 μmol.g−1.h−1 and CO 15.1 μmol.g−1.h−1 having 0.33, 0.59 and 0.1% AQY, respectively. The presence of Cu in CuNi NPs significantly boosts the catalytic performance via metal dilution and synergistic effect, causes the red shift and increases the conductivity, while Ni increases the band gap, thereby achieving a record high CH3OH rate generation.

The effect of filler metal on microstructure and mechanical performance of GTAW inconel 625 at room and elevated temperature

The aim of this study was evaluating the influence of ER321 and ERNiCr-3 filler metals on the mechanical performance of the Inconel 625 gas tungsten arc welded joints at room and elevated temperature and correlating with the microstructure. Optical and scanning electron microscopy was conducted to characterize microstructure features at the fusion and the interfaces. Microhardness measurements, tensile test, Charpy impact test, and creep rupture test were applied to the weldments to investigate the effect of filler metal on mechanical properties of the joints. Creep rupture test was performed at 600 °C under load stresses of 150, 200 and 300 MPa. At high stress levels (300 MPa), nucleation and coalescence of voids accelerates and a ductile fracture with dimple morphology for both filler metals was seen. At lower stress level of 150 MPa, the creep deformation becomes dominant for both weldments and the voids which are mainly micro-creep voids get smaller in size and are located near the precipitates. A 100% increase in stress level (from 150 MPa to 300 MPa), reduces the creep rupture life of the ERNiCr-3 and ER321 welds by about 11 and 30 times, respectively. The results show that stringers of δ-Ferrite in inter-dendritic region of austenite appear in ER321 weldments along with some precipitates which are highly enriched in Ti and C. The formation of the unmixed zone with a different concentration gradient of the elements is observed at the Inconel 625/ER321 stainless steel interface. XRD pattern reveals the formation of (Fe2Mo) Laves phase in ER321 weld metal where the amount of Fe in the weld increases and Mo solubility decreases. ERNiCr-3 weldments show fully austenitic structure and some NbC precipitates. EDS analysis of ERNiCr-3 weld metal confirms high amount of Mo and Nb at the inter-dendritic region, whereas the dendritic core is depleted from Mo and Nb. By applying different filler metals, different fracture morphology was revealed under different loads. A non-uniform hardness profile and the minimum microhardness value of 120 HV were seen in the wide unmixed zone of ER321 weld metal due to its heterogeneous structure and also due to lack of weld metal dilution. It was shown that ER321filler metal does not give an appreciable tensile and impact properties comparing to ERNiCr-3 weldments. The tensile elongation was greater for ERNiCr-3 weldments (13.1%) than ER321 joints (10.2%) andthe average impact toughness of ERNiCr-3 weldments was about two times higher than ER321.

Applying Solidification Theory to Aluminum Weldability and Consumable Development

One defect encountered in the fusion zone when welding aluminum alloys involves solidification cracking (i.e., the tearing apart of grain boundary liquid films at the trailing edge of the weld pool). This problem can often be mitigated by the proper selection of filler metal. Two key engineering examples, one aerospace and one maritime, where this has occurred were examined in terms of alloy development to achieve optimum mechanical properties while maintaining weldability. Specifically, base metal/filler metal systems susceptible to cracking were examined in terms of filler metal dilution. A mechanism for crack growth was presented based upon critical strain rate. Conditions needed for improved weldability through grain refinement were defined based upon the columnar-to-equiaxed solidification theory.

Microstructural and mechanical characterization of parallel layered WC- NiCr weld overlay on 080 M40 steel substrate prepared using additive manufacturing

080 M40 Medium carbon steel has potential applications in axles, shafts, bolts, studs, spindles, automotive components and many more. In high friction applications these steels possess better wear resistance, and after weld overlay, they can exhibit superior properties. Additive manufacturing (AM) is an advanced method in which material in the form of powder or wire is used to form a desired shape. Laser Metal Deposition (LMD) is an AM method which is used in industrial application to recreate, repair and produce corrosion resistance weld overlay on a part. In comparison with conventional overlay techniques such as Plasma Transfer Arc (PTA), Metal Inert Gas (MIG) & Tungsten Inert Gas (TIG); Laser weld overlays are faster techniques which can make thin sections with good metallurgical bond and with high productivity and flexibility. Apart from that it has also advantage of low heat affected zone, minimum metal dilution, and can produce thin layers with good aesthetics. In this paper, 080 M40 steel samples were used as substrate and WC- NiCr powder was weld overlayed using LMD method. Such kind of weld overlays will be had potential application in the field of mining. The weld overlay was deposited in parallel layered fashion and effect of set of parameters like feed rate, dilution, size of the bead and processing speed were used to produce weld overlays of 1 mm thickness. metallurgical, micro structural and mechanical properties of these weld overlay materials have been investigated. These properties are very important in the processing of mining tools as well as other parts produced using the LMD process and also for other future applications. Further effect of laser processing parameters on the resulting properties of these steels weld overlays are discussed.

STUDIES ON EFFECT OF Nb SEGREGATION AND FORMATION OF SECONDARY PHASES OF Ni–Cr–Mo CLAD ON 316L SUBSTRATE BY COLD METAL ARC TRANSFER PROCESS

In current scenario, there is an ever increasing demand for alloys with increased wear resistance under severe working conditions. Ni–Cr–Mo alloy is suitable for surface modification and repairing applications. The Ni–Cr–Mo alloy clad region had cellular-dendrite with Laves phase and complex nitrides/carbides (MX) distributed in the interdendritic regions. Microindentation hardness variation was observed on the interdendritic regions as compared to that of dendritic regions. A new solidification path is confirmed through EDS analysis. Ni, Fe and Cr segregate to the dendritic area, whereas Nb and Mo segregate to the interdendritic region. Ni–Cr–Mo microstructure evolution was studied by optical microscope (OM), scanning electron microscope (SEM) and atomic force microscope (AFM). The Laves and G phases were identified in the Ni–Cr–Mo clad region, confirming superior resistance to corrosion. Pin-on-disc abrasion wear technique confirmed that cladding with low base metal dilution possesses better wear resistance. The mechanism of wear depends on load applied and sliding time. EBSD analysis revealed random texture and grains have same crystallographic orientation across the interface boundary line due to epitaxial growth.

Application of Taguchi method and ANOVA analysis for optimization of process parameters and exothermic addition (CuO-Al) introduction in the core filler during self-shielded flux-cored arc welding

The main factors affecting the mechanical properties of the deposited metal in arc hardfacing are primarily the chemical composition and the cooling rate. The latter depends on the filler materials composition, hardfacing condition (mode), and hardfacing technology, determining the geometric parameters and parameters of the welded bead shape, the amount of deposited metal dilution with the base metal, and the amount of the introduced heat. The goal of this work is to analyze the effect of exothermic addition introduction to the core filler and the effect of welding condition on weld bead morphology, thermal indicators, and mechanical properties of the deposited metal. The deposited metal of the Fe-C-Cr-Cu-Ti-V-Al alloying system was used. The Taguchi technique was adopted as the experimental plan design, as follows: the orthogonal array L9 (3 ^ 4) and signal-to-noise ratio (S/N). The analysis of variance (ANOVA) was also applied for determination of the variables contribution to the dependent parameters. Application of the Taguchi method is simpler, more efficient, and quicker. It requires fewer experiments to determine the optimal values of the studied variables. Microstructural studies using an optical microscope were additionally performed for individual samples of the weld metal with the best mechanical properties, for each of the experimental flux-cored wires. We determined that introduction of CuO-Al exothermic addition of to the core filler had a significant effect on such indicators of the weld bead morphology as the weld reinforcement height and the weld reinforcement form factor (WRFF). Introduction of exothermic addition (CuO-Al) to the core filler had a significant effect on the welding current (I), heat input rate (HIR), and microhardness. The arc voltage (Р(Ua) = 45.8 %) had the greatest influence on the microhardness value, while the percentage of exothermic addition in the core filler (P (EM) = 26.9%) and the wire feed rate (P (WFS) = 21.5%) had a smaller effect. It was shown that it is important to take into account complex parameters, such as dilution variation and weld reinforcement form factor (WRFF) for the geometric characteristics of the weld bead and heat input rate (HIR) for heat indicators in order to optimize hardfacing conditions and composition of the core filler (introduction of exothermic addition). According to the results of the article, the value is the most correlated with the average values of microhardness.

Bimetallic RuNi nanoparticles as catalysts for upgrading biomass: metal dilution and solvent effects on selectivity shifts

Core–shell RuNi catalysts are prepared from organometallic complexes and PVP as stabilizers under one-pot conditions. The synergistic effect between Ru and Ni activity in furfural hydrogenation depends on the nanoparticle composition.

Direct comparison of Cold Metal Transfer to laser hot-wire cladding for AISI 4340 structural steel repair

Repair, rather than replacement, of large, high-value structural components can reduce overall operating costs, with wire-based cladding techniques preferable due to their relatively high deposition rates. Two such techniques, laser hot-wire cladding and Cold Metal Transfer, are particularly attractive for their low heat input, which reduces distortion, filler metal dilution and thermal effects on the substrate. However, literature studies on the use of these techniques for structural steel repair are limited, with no studies offering a direct comparison of their performance. In the present work, laser hot-wire cladding is directly compared to Cold Metal Transfer for the repair of AISI 4340 structural steel. Simulated repairs using the same base/filler metal and joint geometry are characterised in terms of distortion, microstructure, tensile and impact properties. The results show that, despite having similar laser and arc energies, the two techniques resulted in significantly different properties, generally due to differences in process efficiencies.

Spin transition properties of metal (Zn, Mn) diluted Fe(phen)2(NCS)2 spin-crossover thin films

We report here the effect of metal (Zn and Mn) dilution on the spin transition of Fe(phen)2(NCS)2 thin film spin-crossover (SCO) complex. The SCO complexes are deposited on glass and indium-tin-oxide (ITO) coated glass by dip-coating technique. The growth of the films is clearly confirmed by the appearance of the sharp optical absorption band at 521–540 nm corresponding to 1A1g to 1T1g ligand field absorption of the SCO complex. Although the microstructure of the films remains unaffected by metal dilution, substitution of Fe(II) by either Zn(II) (diamagnetic) or Mn(II) (paramagnetic) results in subtle changes in the bonding environment of the host metal as inferred form X-ray diffraction and Raman studies. The high spin to low spin (or vice versa) transition can be triggered either by electric field or magnetic field as revealed in the measured current (I)–voltage (V) profile or magnetization data of the films. The data further shows the effect of metal dilution on the spin transition temperatures(T1/2), produced hysteresis loop width and loop area, which are the crucial parameter for fabricating spin-based room temperature switching devices.

Bead by bead study of a multipass shielded metal arc-welded super-duplex stainless steel

The present study aims at investigating bead geometry and the evolution of microstructure with thermal cycles in multipass shielded metal arc welding of a V-groove 13-mm type-2507 super-duplex stainless steel (SDSS) plate. The weld consisted of 4 beads produced with arc energies of 0.81–1.06 kJ/mm. The upper beads showed lower base metal (BM) dilution than the first bead. Thermal cycles were recorded with thermocouples, indicating that the cooling rate decreased in the as-deposited weld zone when adding a new bead. Ferrite fraction in the as-welded condition was lower for the upper beads. The austenite grain morphology in reheated passes varied depending on the local peak temperatures and the number of reheating passes. Sigma phase precipitated in a location reheated by the third and fourth passes that was subjected to a critical peak temperature for sigma precipitation. Ferrite content, measured using image analysis and Fisher FERITSCOPE technique, showed that the ferrite fraction moved toward 50/50% in the weld metal with an increasing number of reheating cycles. Finally, a schematic map showing an overview of the microstructure in the multipass SDSS weld was introduced.

Dissimilar Metal Joining of 304 Stainless Steel to SMA490BW Steel Using the Filler Metal Powders with a High-Entropy Design

High-entropy alloys having excellent properties are particularly suitable for the application as the filler metals in welding. In the present study, multi-component mixed powders of FeCoCrNiMn and CrFeNi2.4Al0.6, based on a high-entropy design, as well as the comparative 316L stainless steel powders, were used as the filler metals, to achieve the dissimilar welding between 304 stainless steel and SMA490BW steel by laser deposition welding. By comparative analysis of the microstructure and mechanical properties of three types of joints, the feasibility and weld-ability of the filler metal powders based on a high-entropy design were studied. It was found that the melting of base metal (BM) and weld metal dilution had an impact on the set high-entropy component in the weld zone. And high-entropy structures were achieved in the weld zone by using the powders of CrFeNi2.4Al0.6. Compared to the BM of SMA490BW steel, three types of joints presented a higher notched tensile strength and had a better corrosion resistance. The joint welded using the powders of CrFeNi2.4Al0.6 had the lowest hardness value in the weld zone, in which the joint was fractured during the notched tensile tests. The other two joints fractured near the notch in the SMA490BW steel side. Transgranular fracture and a typical dimple fracture were observed in the fractured joints. In this work, multi-component mixed powders of FeCoCrNiMn and CrFeNi2.4Al0.6, based on a high-entropy design, were used as the filler metals to achieve the dissimilar welding of 304 stainless steel to SMA490BW steel by laser deposition welding. And a detailed investigation of microstructures and mechanical properties of those dissimilar joints was carried out to explore the feasibility and weld-ability of the filler metal powders based on a high-entropy design.

Adding a Suite of Chemical Abundances to the MACER Code for the Evolution of Massive Elliptical Galaxies

Abstract We add a suite of chemical abundances to the MACER (Massive AGN Controlled Ellipticals Resolved) 2D code, by solving 12 additional continuity equations for H, He, C, N, O, Ne, Mg, Si, S, Ca, Fe, and Ni with sources from AGB stars and Type Ia and II supernovae with metal yields based on standard stellar physics. New stars, formed in Toomre unstable circumnuclear disks (of a size ≲150 pc), are assumed to have a top-heavy initial mass function with a power index of 1.65. The metal dilution effects due to cosmic accretion are also included. With a high resolution of a few parsecs in central regions, resolved black hole accretion, and active galactic nucleus (AGN) feedback, we can track the metal enrichment, transportation, and dilution throughout the modeled massive elliptical galaxy of velocity dispersion ∼280 km s−1. We retrieve the chemical composition of the broad absorption line (BAL) winds launched by the central AGN, synthesize the X-ray features of the hot ISM, and find that (1) the simulated metallicity in the BAL winds could be up to ∼8 Z ⊙, while that of the hot ISM in the host galaxy is ∼2.3 Z ⊙, matching well with SDSS observations of BLR gas; (2) the X-ray emitting hot gas is metal-enriched with a typical value ∼2.5 Z ⊙; (3) the circumunuclear cold gas disk, where the metals are condensed, further enriched, and recycled, plays a critical role in the metal enrichment; (4) the black hole accretion rate linearly correlates with the star formation rate in the circumnuclear disk, i.e., , but lagged in time by roughly 106 yr.