Major Alloying Elements Research Articles

Characterization of Sodium Thermal Insulation Reaction Product and its Effect on Fatigue Crack Growth in 316 LN Austenitic Steel

Though sodium is the most preferred coolant for fast breeder reactors due to excellent heat transfer capabilities, its high chemical reactivity poses a concern during accidental leaks. Despite defense in depth in various levels for protecting the sodium leaks in the heat transport circuits, small undetected leaks may lead to localized degradation of structural material due to deposition of reaction products in the leak zone. Experiments have been conducted by exposing SS-316 LN specimens to sodium–glass wool interaction zone at 300 °C in air to study the influence of reaction products on chemical composition and crack growth properties. Post-exposure X-ray diffraction analysis of the samples revealed presence of silicates and aluminates of sodium in the outer layers, and complex ternary and quaternary oxides of sodium, iron, chromium and nickel in the inner layers. Scanning electron microscopy analysis revealed deposition of oxides on the exposed surface. Elemental analysis of the samples carried out by energy-dispersive spectroscopy indicated leaching of major alloying elements like chromium, nickel and iron to a depth of about ~ 25 µm from the exposed surface. Room-temperature fatigue crack growth studies on the exposed specimen shown considerable reduction in crack initiation (threshold) fracture toughness range ΔKth.

Novel Mn and Si alloyed complex phase steel for automotive applications

Automotive industries require materials with higher strength, plasticity and crashworthiness, aiming for 3rd generation of advanced high strength steels (AHSS) with medium Mn, Si and minor alloying elements. In this investigation, 3rd generation AHSS were synthesized using a vacuum arc melting furnace with manganese (Mn) and silicon (Si) as major alloying elements as well as minor additions such as Cr, Al, Ni, etc. The steels thus developed were characterized using FE-SEM, XRD, microhardness tester, universal testing machine (UTM) and 3-dimensional Atom Probe Tomography (APT). The alloy steels after casting and homogenization were subjected to hot rolling at 1100 °C, with rolling exit temperature 900 ± 50 °C. The FE-SEM micrographs in SE mode revealed a complex phase microstructure with martensite, ferrite, bainitic ferrite and retained austenite in the specimens obtained after rolling and air cooling. The microhardness of the developed alloys is found in the range of 395–502 VHN in the hot-rolled and air cooled condition of the specimen. The tensile strength of alloys was measured to be in the range of 1412–1614 MPa with elongation of 12.12 %–18.92 %. The analysis of fracture surfaces after tensile tests for developed alloys revealed that Alloy 1 (Fe-4Mn-1.5Si) had dimples indicating ductile fracture while Alloy 2 (Fe-6Mn-1.5Si) has a mixture of dimples and facets, and Alloy 3 (Fe-8Mn-1.5Si) has lower dimples but larger facets, confirming quasi-ductile fracture with a lower ductility limit of 12.12 %. Atom Probe Tomography was performed to study the complex phase structure at nanoscale through re-distribution of carbon and other alloying elements. 3D APT revealed the presence of very fine retained austenite film of thickness ∼4–5 nm and carbon content of 6–8 at.%. This complex phase microstructure obtained after hot rolling and normalizing is made of very fine bainitic ferrite with film type retained austenite providing TRIP effect, in addition martensite and ferrite resulting in high strength.

Synergic investigation of microstructure, precipitation, and micro-segregation on Inconel 825 weldments: A comparative study between GTAW and EBW

Inconel 825, a Ni–Fe–Cr alloy highly regarded for its exceptional corrosion resistance and high-temperature strength. This investigation studies the effect of heat input, precipitation, and micro segregation of Inconel 825 weldments and compares the effectiveness of two welding techniques: gas tungsten arc welding (GTAW) and electron beam welding (EBW). The findings indicate that increasing heat input generally enhances weldment quality by reducing the lack of penetration. However excessive heat input in GTAW leads to root cracking and solidification cracking; while EBW demonstrates better control over undercut and maintains consistent weld quality even at higher heat inputs. Both GTAW and EBW samples exhibit dendritic grain morphologies with distinctive grain boundaries. Precipitates, such as Al4C3 and TiN, are observed in both processes, contributing to improved mechanical properties. While GTAW weldments show some degree of segregation for Mo, Cu, Ti, and Al, EBW weldments demonstrate negligible segregation for major alloying elements but micro-segregation of Ti and Al. EBW weldments additionally showcase higher average hardness, superior tensile strength, and ductility compared to GTAW weldments. This can be attributed to lower heat input, faster cooling rates, and a reduced rate of elemental segregation. Fractographic analysis reveals the presence of voids and micro-voids, indicating a ductile mode of failure for both GTAW and EBW samples. These void characteristics vary based on the heat input and microstructural features.

In situ chemical analysis of duplex stainless steel weld by laser induced breakdown spectroscopy

The high corrosion resistance and good mechanical properties of duplex stainless steel (DSS) are due to its special chemical composition, which is a balanced phase ratio of ferrite (α) and austenite (γ). Many industrial applications require the integration of DSS components. For this, Gas tungsten arc welding (GTAW) is an excellent choice, as it allows an automated operation with high reproducibility. However, when the weld pool solidifies, critical ratios of α- and γ- phases can occur, which lead to solidification cracking, increased susceptibility to corrosion, and a decrease in ductility and critical strength. Previous studies have shown that these defects can be caused by the accumulation of manganese and chromium in the heat affected zone (HAZ), requiring ongoing monitoring of this accumulation. A suitable method for such monitoring is laser-induced breakdown spectroscopy (LIBS), which can be used in two operating modes: calibration using standard reference samples and calibration-free. Unlike conventional quantitative LIBS measurements, which require reference samples to generate a calibration curve, calibration-free LIBS (CF-LIBS) allows chemical compositions to be determined solely from the emission spectrum of the plasma. Numerous publications show that CF-LIBS is a fast and efficient analytical method for the quantitative analysis of metal samples. In this work, CF-LIBS is applied to spectra obtained during GTAW DSS welding and the result is compared with those obtained by PLS analysis. A good correlation was found between both types of analysis, demonstrating the suitability of the CF-LIBS method for this application. The CF-LIBS method has a significant advantage over conventional LIBS due to the rapid in situ measurement of concentrations of major alloying elements without calibration procedure. This, combined with fast feedback and appropriate adjustment of welding parameters, helps prevent welding defects.

Abnormal Grain Growth and Pseudoelasticity of Industrially Processed Fe–Mn–Al–Ni Shape Memory Alloy Joined by Metal Inert Gas Welding

The effect of metal inert gas welding on the microstructure, abnormal grain growth and the pseudoelastic properties of industrially processed Fe–Mn–Al–Ni shape memory alloy sheets were studied. Square-butt welds were manufactured using similar filler material. The influence of alternating mean arc linear energy on the microstructure of the individual zones is shown. A correlation between the process parameters, the associated heat input, the grain morphology and the α/γ-ratio could be deduced. As the mean arc linear energy increases, the α/γ-ratio in the fusion zone and the heat-affected zone increases. To evaluate the influence of the welding process on abnormal grain growth, a post-weld cyclic heat-treatment was carried out. Although no loss of major alloying elements in the fusion zone was observed after welding, metal inert gas welding has a significant effect on grain growth upon cyclic heat treatment. While abnormal grain growth occurred in the base material, a polycrystalline microstructure characterized by significantly smaller grain sizes was visible in the former fusion zone. Incremental strain tests revealed severe plastic deformation near the grain boundaries in the former fusion zone. However, the grain boundaries of the bamboo-like grown grains in the base material turned out to be more critical for structural failure.

Unraveling the leverage effect in phases stability and mechanical properties of Al-Zn-Mg-Cu alloy

In order to further improve the comprehensive performance of advanced aluminum (Al) alloys, especially 7xxx Al-Zn-Mg-Cu alloys, tuning the relative ratios between major alloying elements (Zn, Mg, Cu) while maintaining the total alloying amount has been widely adopted. However, the specific influence of these relative element ratios on various properties has yet to be well understood. In this work, the leverage effect of those alloying element pairs (Al:Cu, Mg:Zn, Cu:Mg, and Cu:Zn) on the phase stability and mechanical properties of Al-Zn-Mg-Cu alloy is systematically investigated by means of first-principles calculations, cluster expansion, and quasi-harmonic Debye model. The tradeoffs in formation energy, elastic strength, and anisotropy are unraveled when the element pairs deviate from the equal ratio (1:1), indicating a strong leverage effect in element pairs. Among those element pairs, Al:Cu and Cu:Mg are the major lever in phase stability, in which the stable phase reversed on the two sides of 1:1; while the Mg:Zn lever dominates the elastic strength and anisotropy. Cu:Zn, on the other hand, has less impact on material properties. The underlying mechanism of those leverage effect is analyzed by the bonding electron density and lattice distortion around the major alloying elements. Our results are in good agreement with experimental observations and clarify the controversaries of those element pairs on the material properties. The weight of each lever could provide a practical guidance to the optimization of the alloy composition of 7xxx Al-Zn-Mg-Cu alloys, and also shed lights on the development of other advanced alloy systems.

Industrially produced 2.4 GPa ultra-strong steel via nanoscale dual-precipitates co-configuration

An ultra-high strength martensitic steel, strengthened by the dual-precipitation of NiAl and M2C nano-particles, has been successfully developed and produced on an industrial scale. It has achieved a remarkable tensile strength of 2467 MPa and exhibited ductility approaching 10%. The precipitation configurations of NiAl and M2C nano-particles during ageing at 510 °C for durations ranging from 0.5 to 10 h were characterized using atom probe tomography. The results indicate that the preferential precipitation of NiAl, facilitated by minimal lattice misfit and low interfacial energy, promotes the uniform nucleation of M2C particles within the matrix while restricting their growth. As a result, both types of precipitates maintain a high number density. With increasing ageing time, the distribution density of the precipitates decreases, their size increases and the increase in yield strength gradually decreases. Furthermore, the addition of element cobalt effectively reduces the diffusivity of other major alloying elements, synergistically inhibiting the growth of NiAl and M2C particles. The dual precipitates co-configuration provides a substantial hardening effect (1046 MPa at 510 °C for 220 min) compared to the individual hardening effect of M2C observed in AerMet100 steel.

Ti-Al-based alloys with Mo: high-temperature phase equilibria and microstructures in the ternary system

ABSTRACT Molybdenum is one of the major alloying elements in TiAl-based alloys for high-temperature structural applications developed over the last decades. This is due to its stabilising effect on the (βTi) phase at high-temperatures, which crucially improves the hot-workability of such alloys. For further alloy development, an exact knowledge of the phase equilibria in the Ti–Al–Mo system is essential. However, there are still uncertainties and inconsistencies related to the ternary phase diagram. In this study, a series of ternary alloys was produced and heat-treated between 700 and 1300 °C. Composition, structure, and thermal stability of the phases were analysed and the resulting phase equilibria were established by applying a combination of scanning electron microscopy (SEM), electron probe microanalysis (EPMA), differential scanning calorimetry (DSC), and high-energy X-ray diffraction (HEXRD). From these results, a series of partial isothermal sections is obtained illustrating the phase equilibria in the Ti-rich part of the Ti–Al–Mo system.

Microstructural and Nanoindentation Investigation on the Laser Powder Bed Fusion Stainless Steel 316L.

Additive manufacturing (AM) of stainless steel is more difficult than other metallic materials, as the major alloying elements of the stainless steel are prone to oxidation during the fabrication process. In the current work, specimens of the stainless steel 316L were made by the powder laser bed fusion (P-LBF) additive manufacturing process. These specimens were investigated by electron microscopy and micro-/nano-indentation techniques to investigate the microstructural aspects and the mechanical properties, respectively. Compositionally, a similar wrought stainless steel was subjected to identical investigation, and used as a benchmark material. The microstructure of the P-LBF-processed alloy shows both equiaxed and elongated grains, which are marginally smaller (3.2-3.4 μm) than that of the wrought counterpart (3.6 μm). Withstanding such marginal gain size refinement, the increase in shear stress and hardness of the L-PBF alloy was striking. The L-PBF-processed alloy possess about 1.92-2.12 GPa of hardness, which was about 1.5 times higher than that of wrought alloy (1.30 GPa), and about 1.15 times more resistant against plastic flow of material. Similarly, L-PBF-processed alloy possess higher maximum shear stress (274.5-294.4 MPa) than that of the wrought alloy (175.9 MPa).

The application of EET in high-entropy alloy

High-entropy alloy with multi-principal elements is a novel design concept for the field of alloy, which breaks through the traditional alloy development frame based on “one or two major alloy elements”. High entropy alloy composed of different metallic elements (generally ≥ 5) can present different novel properties by changing mole ratios or elements. In this work, the valence electron structure of high entropy alloys with compositions near Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 was studied using the Empirical Electron Theory of Solid and Molecules (EET). The predicted results agree well with the experimental data. Results shows that EET can be used to forecast the HEAs’ properties and design the constituent of HEAs.

Roles of major alloying elements in steels and alloys on corrosion under biomass hydrothermal liquefaction (HTL) conversion

Hydrothermal liquefaction (HTL) is a promising thermochemical technology to convert wet biomass and biowaste streams into bioenergy products. Significant knowledge gaps exist due to reactors’ corrosion damage. This study investigated the roles of alloying elements (Cr, Fe, Ni and Mo) on corrosion in simulated HTL environments via thermodynamic calculation and autoclave tests. Cr acts as the dominant alloying element, and the tested Fe-based steels and Ni-based alloys with Cr content over about 16% exhibit satisfied resistance to the HTL environments. Influences of alloying elements Ni and Mo are different depending on Cr content in the steels and alloys.

Feasibility of a Low-Power, Low-Resolution Laser-Induced Breakdown Spectroscopy Instrument for Analysis of Nickel Alloys: Quantification of the Major Alloying Elements and Classification.

A simple cost-effective laser-induced breakdown spectroscopy (LIBS) instrument was used for quantification of major elements in several nickel alloys and also sorting them. A compact low-power diode-pumped solid-state laser and a miniature low-resolution spectrometer were assembled for the LIBS instrument. Material properties of the nickel alloys depend mainly on the composition of the major elements, Ni, Cr, and Fe, ranging from a few to ∼60 wt%. The emission peaks at 547.7 nm, 520.4 nm, and 438.1 nm for Ni, Cr, and Fe, respectively, were chosen for this analysis. The analytical performance was found to be enough for the quantification of Ni, Cr, and Fe in the nickel alloys. Limits of detection and accuracy were estimated to be a few weight percent (wt%) and measurement precisions were less than 10% in terms of relative standard deviation. The calibration performance of this intensity-based method was compared with that of the "ratio method" which is used in conventional optical emission spectroscopy analyses. The comparison indicates that the intensity-based method is more appropriate with the low-performance LIBS instrument that detects emission peaks of only a few major elements. Also, multivariate modeling of the six different nickel alloy samples based on the emission peak intensities of Ni, Cr, and Fe was performed using k-nearest neighbors (KNN) and linear discriminant analysis (LDA). The KNN and ordinary LDA models showed 95.0% and 98.3% classification correctness for the separate test data set, respectively. To improve classification performance further, the two-step LDA model was trained. In this approach, the two closest sample classes responsible for the decrease in the classification correctness were separately modeled in the second step to exploit their difference effectively. The two-step LDA model showed 100% correctness in classifying the test objects. Our results indicate that such a low-performance LIBS instrument can be effectively utilized for quantitative analysis of the major elements in the nickel alloys and their rapid identification or sorting in combination with an appropriate multivariate modeling algorithm.

Bulk Recycling of Ni-Cr-Mo Dental Alloy - A Sustainable Approach

Many dental alloy manufacturers instruct not to recast alloys, but the dental laboratories reuse the casting surplus for economic reasons. It is a controversial topic in dental practice, so the present study attempts to assess the effects of recasting Ni-Cr-Mo alloys. Three sets of alloy pellets were recast. The first set was melted and allowed to solidify. The second and third sets were recast two times and three times, respectively. The elemental composition of all the recast samples was analysed using ED-XRF (Energy Dispersive X-ray Fluorescence) spectrometer. The variation in the chemical composition for the number of recasting was reported. It was observed that the recasting for one time doesn't change the elemental composition to a considerable extent. However, further increase in the number of recasting two and three times, the depletion of the major alloying elements (Ni, Cr, and Mo) was notable. Hence, the current study intends to calculate the exact amount of the depleted elements after each recast. Also, to have a theoretical analysis of the elements necessary for making a master alloy that can be added during the recasting to avoid changes in elemental composition. Moreover, the microstructure of the recast samples was observed using an optical electron microscope (OEM). No drastic variation in the microstructure was observed for the alloy with several melting and solidifying cycles, except for the orientation of the dendritic arm. Furthermore, to confirm the mechanical strength of the recast alloy Vickers microhardness test was conducted. The average microhardness of the base Ni-Cr-Mo alloy was 216 HV, and recasting once does not affect the hardness value. However, the three-time recast alloy showed only a 9% decrement. Finally, it can be concluded that the number of recasting can be as many times provided depleted elements are added in exact proportion after each recast. The current research suggests recycling dental alloys in bulk outside a dental clinic, and a dentist should responsibly segregate different base metal alloys and promote sustainable dentistry.

Effect of Functionally Graded Material (FGM) Interlayer in Metal Additive Manufacturing of Inconel-Stainless Bimetallic Structure by Laser Melting Deposition (LMD) and Wire Arc Additive Manufacturing (WAAM).

Bimetallic structures manufactured by direct deposition have a defect due to the sudden change in the microstructure and properties of dissimilar metals. The laser metal deposition (LMD)-wire arc additive manufacturing (WAAM) process can alleviate the defect between two different materials by depositing the functionally graded material (FGM) layer, such as a thin intermediate layer using LMD and can be used to fabricate bimetallic structures at high deposition rates with relatively low costs using WAAM. In this study, the LMD-WAAM process was performed, and the microstructure of the fabricated bimetallic structure of IN625-SUS304L was investigated. The microstructure of the FGM zone of the LMD-WAAM sample was mainly fine equiaxed dendrite morphologies. In contrast, coarse columnar dendrite morphologies constituted the WAAM zone. The composition of the major alloying elements of the LMD-WAAM sample gradually changed with the height of the deposited layer. The microhardness of the LMD-WAAM sample tended to increase with an increasing Inconel content. In the case of the LMD-WAAM sample, the fracture occurred near the interface between 25% IN625 and 0% IN625; in the WAAM sample, the final fracture occurred in SUS304L near the interface. The tensile strength of the LMD-WAAM samples was inversely proportional to the laser power. The results showed that the LMD-WAAM samples had 8% higher tensile strength than the samples fabricated using only WAAM.

Effects of Ferro-Silicon addition, heat-treatment and plastic deformation on corrosion resistance of 6063 Aluminum Alloy

6063 aluminium alloy is widely used in architectural applications such as window and door frames because of its nice appearance and acceptable strength. Its major alloying elements are magnesium and silicon. Not many studies focused on the influence of plastic deformation and the alloy content on post-processing quality and corrosion resistance of the alloy have been published. Considering the influence that variation in chemical composition could have on the properties of the alloy, this work aims to investigate the effects of Ferro-Silicon addition, heat-treatment and cold rolling on post-processing quality and corrosion resistance of 6063 Aluminium Alloy. 5000 g of Aluminium 6063 alloyed with 500 g of ferrosilicon was produced. Cast samples from the alloy were homogenized at 350 ºC before cold rolling in the range of 10%, 15%, 20%, 25%, and 30% reduction. The corrosion behaviour of the produced alloy was evaluated using a potentiodynamic test in a 3.5wt % sodium chloride solution. The results show that the addition of FeSi and cold- rolling results in improved mechanical properties but has little effect on corrosion resistance. Heat-treatment has not caused significant impact in corrosion resistance and mechanical properties of the alloy.

Role of Thermo-Mechanical Treatment on Creep Deformation Behaviour of Reduced Activation Ferritic Martensitic Steel

<div class="section abstract"><div class="htmlview paragraph">To enhance the microstructural and mechanical properties of Reduced Activation and Ferritic-Martensitic (RAFM) steel thermo mechanical treatment (TMT) was performed on as received Normalised and Tempered steel (N+T). The RAFM with 9Cr-1W-0.06Ta major alloying elements steel was used in the study in N+T and TMT conditions. The refinement in microstructure and precipitates was observed in TMT steel in comparison to N+T steel. There is a drastic improvement in mechanical properties such as hardness, tensile properties are observed without losing the ductility. The creep deformation behaviour of thermo-mechanical treated steel and N+T steel were studied at different stress levels at 823 K. The comparative creep rupture and strain properties were studied, and various creep deformation regimes were also analysed for both the conditions of steel. The rate of exhaustion of primary creep (r), minimum creep rate and time spent in primary and tertiary creep regime, rate of acceleration of tertiary creep and time to reach the onset of tertiary creep. Microstructural studies on Optical and Scanning electron microscopy and transmission electron microscopy results were correlated with the mechanical properties of steels. On a whole, a comparative investigation was performed on various reasons for drastic improvement in tensile and creep rupture properties of TMT steel than the steel in N+T steel and necessary microstructural investigation support is considered.</div></div>

Heterogeneous microstructure of duplex multilayer steel structure fabricated by wire and arc additive manufacturing

Wire and arc additive manufacturing (WAAM) is suitable for fabricating multimaterial dense structures in various additive manufacturing technologies. Watanabe et al. [1] reported that a unique two-stage stress–strain curve was observed during tensile testing of a duplex multilayer steel structure fabricated by WAAM. The material behavior was explained by the transformation-induced plasticity, which was attributed to a decrease in the austenite phase observed after testing using X-ray diffraction at three representative points of the tensile test specimen. However, the deformation mechanism was unclear from the viewpoint of the composite structure mechanics. In this study, the heterogeneous microstructure of the steel structure was investigated for the duplex layer region to infer the relationship between the material response and underlying deformation mechanism. The distributions of the phase and major alloy elements indicated that the layers melted and mixed during WAAM, and the multilayer structure subsequently changed compared to the design layout. The WAAM structure was composed of two dual-phase layers containing different volume fractions of the martensite phase. Hence, the austenite phase in the martensite-rich layer initially deformed and then transformed to the martensite phase during tensile testing. Consequently, the strength of the martensite-rich layer was recovered to the micromechanically estimated level and the two-stage stress–strain curve was generated. Thus, this paper presents the potential of multimaterial WAAM for controlling microscopic heterogeneities and their material responses by adjustment of the process parameters. • Unique two-stage stress–strain curve obtained from WAAM duplex multilayer structure. • Deformation mechanisms investigated from microscopic heterogeneities viewpoint. • The multilayer structure differs from the design layout because of melt–mixing. • Strain-induced transformation in martensite-rich layer led to two-stage response.

Development of friction stir powder deposition process for repairing of aerospace-grade aluminum alloys

This paper presents development of a novel friction stir powder deposition (FSPD) process for potential repairing applications of aerospace-grade aluminum alloy AA6061-T6. Powder form of the deposition material was thermo-mechanically processed at a temperature below its melting point. Influence of various process parameters on thermal cycles, deposition quality, deposition height, microstructure, and mechanical properties have been studied. Higher degree of deformation resulted in a dynamically recrystallized fine-grained microstructure which gave better mechanical properties. EDS study revealed uniform distribution of the major alloying elements throughout the deposition. Best quality deposition showed maximum microhardness and wear rate 0.84 and 1.07 times respectively than the substrate AA6061-T6 alloy. FSPD process is found to be capable of depositing maximum height of 0.45 mm, maximum deposition efficiency of 22% with an energy consumption of 73.7 J/mm 3 per unit deposition material consumption. Moreover, it used current in the range of 5-7 Ampere. This research shows that FSPD process can provide considerable cost and energy savings over fusion-based additive manufacturing processes making it a viable alternative for repairing aerospace-grade aluminum alloys. • Developed friction-stir powder deposition as a solid-state AM process for aerospace-grade Al alloys. • Max. deposition height: 0.45 mm; deposition efficiency: 22%; Avg. peak temperature: 293 °C. • Higher deformation gave dynamically recrystallized fine-grained microstructure. • Uniform distribution of alloying elements in the deposition. • Deposition microhardness and wear rate are 0.84 and 1.07 times than substrate AA6061-T6.

Exploring temperature-controlled friction stir powder additive manufacturing process for multi-layer deposition of aluminum alloys

This paper presents preliminary study on multi-layer deposition of aerospace grade Al 6061 alloy by novel friction stir powder additive manufacturing process. Minimum temperature of deposition was in-situ maintained using close loop temperature-controlled system for minimizing thermal gradient in the build direction. Maximum temperature during the deposition was monitored in-situ using pyrometer and thermal imaging camera. Use of a tool with circumferential and radial grooves and continuous external heating facilitated smooth three-layer deposition of Al 6061 alloy with 60% deposition efficiency and 417°C as maximum deposition temperature. Larger value of temperature at deposition zone improved material flowability and deposition quality. Microstructure of multi-layer deposition found to consist of fine sub-grains. Element analysis showed uniform distribution of major alloying elements in it. Phase analysis revealed Al along with Mg2Si hardening precipitates. Tensile strength and microhardness were close to the commercially available wrought AA6061-T4 alloy. It showed ductility with 16% elongation. The presented process is a viable alternative to fusion-based additive manufacturing processes for multi-layer depositions of aerospace grade and other lightweight alloys which are difficult-to-additively-manufacture.

Improvement of Exotic Material Verification Using XRF

While various common alloys, such as steels, titaniums, and more recently aluminums, have been tested and inspected using X-ray fluorescence spectroscopy (XRF) for decades, uncommon and niche alloys can produce surprising and unusual results. The ability to identify the base metal, major alloying elements, and trace materials in these alloys is critical to XRF testing and inspection procedures. Modern XRF instruments and software can quickly and easily characterize standard and common alloys, such as low-carbon steel, grade 5 titanium, and 6000 series aluminum; detected signals from the metals are generally discrete and strongly pronounced. Less common alloys, such as nickel superalloys and uraniums, present a greater analytical hurdle for rapid on-site testing, grading, and inspection. These exotic materials contain either weaker signals from the alloying elements or nonunique signatures, preventing accurate quantification. Standardization adjustments through software improvements increase the testing accuracy for these uncommon alloys, bringing their results in line with those from more traditional alloys. By modulating the detection energies of interest, the robust calculation can greatly surpass standard, out-of-the-box performance without the need for any inspector input. These improvements can provide greater inspection accuracy on a wider variety of rare and valuable alloys into the future.