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The persistence of pharmaceuticals and personal care products (PPCPs) in water has been a cause for concern for several years. Many studies have successfully used TiO2/UV photocatalysis to remove these compounds from water. In order to optimize these systems for large-scale water treatment, the effects of the reaction matrix, methods to improve energy efficiency, and methods for easy catalyst separation must be considered. The following study examines the photocatalytic degradation of a cocktail of 18 PPCPs using a porous titanium–titanium dioxide membrane and the effect of solution pH on kinetic rate constants. The addition of methanol to the reaction—commonly used as a carrier solvent—had a significant effect on kinetic rate constants even at low concentrations. Solution pH was also found to influence kinetic rate constants. Compounds had higher kinetic rate constants when they were oppositely charged to the membrane at experimental pH as opposed to similarly charged, suggesting that electrostatic forces have a significant effect. The controlled periodic illumination of UV–LEDs was also investigated to increase photonic efficiency. The dual-frequency light cycle used did not cause a decrease in degradation for many compounds, successfully increasing the photonic efficiency without sacrificing performance.

Conventional electrospark deposition (ESD) processes used in industry are well suited to the coating and repair of small areas for the purpose of hardfacing, corrosion resistance, or dimensional restoration. Although significant advances have been made in the range of materials that can be processed, the comparatively slow deposition rate limits the potential applications of a traditional manually operated ESD process. In this study, an automated ESD system was demonstrated for the application of Ni-based superalloy (Inconel 718) coatings on Ni- and Fe-based substrates. A preliminary study was used to determine the influence of process parameters on an automated system, with capacitance, voltage, electrode force, and electrode travel speed parameters chosen to provide higher deposition rates while maintaining high deposition quality. A comparison of Inconel 718 and 316L stainless steel substrates found that the influence of substrate composition on coating hardness and coating composition was limited to the first 40um. These results pave the way for ESD of larger-area coatings and longer-duration repairs without the need for human operators.

Metal additive manufacturing processes can produce geometrically complex and lightweight components. While conventionally manufactured components are frequently assembled to form larger parts, additive manufacturing can be used to print an entire part without needing any assembly. However, additive manufacturing processes are frequently limited in the size of the part they can produce, and it is often more economically favourable to conventionally manufacture larger or simpler geometries, such as large sheets. In this study, we demonstrate the use of a resistance joining process to facilitate the assembly of additive manufactured components. Projections are designed into additive manufactured parts to allow for joining with a conventional metal sheet. Joint performance is evaluated as a function of design choices, including the type of infill, part thickness, and proximity to adjacent joints, as well as the resistance joining process parameters. High strength joints capable of withstanding an applied torque of up to 80 Nm were obtained and functional parts were assembled to a conventionally manufactured sheet as a demonstration of the process. Incorporating projections for resistance joining into the design stage of additive manufactured parts has the potential to facilitate the use of additive manufactured components in larger assemblies and broaden the adoption of additive manufacturing in industry.

Studies on the detrimental effect of liquid metal embrittlement cracks on resistant spot weld joint strength have shown conflicting results. To help understand the cause of these discrepancies, thi...

Ceramic-reinforced metal matrix composites (MMCs) display beneficial properties owing to their combination of ceramic and metal phases. However, the properties are highly dependent on the reinforcing phase composition, volume fraction and morphology. Continuous fiber or network reinforcement morphologies are difficult and expensive to manufacture, and the often-used discontinuous particle or whisker reinforcement morphologies result in less effective properties. Here, we demonstrate the formation of a co-continuous ceramic-reinforced metal matrix composite using solid-state processing. Binder jet additive manufacturing (BJAM) was used to print a nickel superalloy part followed by post-processing via reactive sintering to form a continuous carbide reinforcing phase at the particle boundaries. The kinetics of reinforcement formation are investigated in order to develop a relationship between reactive sintering time, temperature and powder composition on the reinforcing phase thickness and volume fraction. To evaluate performance, the wear resistance of the reinforced BJAM alloy 625 MMC was compared to unreinforced BJAM alloy 625, demonstrating a 64 % decrease in the specific wear rate under abrasive wear conditions.

It is well known that the reprogrammable device is one of the important needs for circuit design. In this paper, nanolayered TiO2 and maple leaves (ML) are combined to form a functional layer (TiO2...

The transportation industry is facing increasing pressure to lightweight vehicles and improve fuel economy. One option is the use of low-density aluminum alloys rather than steels. However, adoption of aluminum alloys is hampered by challenges during the welding of aluminum to steel. Here, an electrospark deposition AA4043 interlayer is applied for the dissimilar resistance spot welding of an aluminum alloy (AA5052) to a galvanized dual phase steel (GI DP600). A minimum 30% tensile lap-shear strength increase is obtained using this interlayer. This manufacturing technique has the potential to allow for greater adoption of aluminum alloys in vehicle lightweighting applications.

In this work, C-doped TiO2 nanorods were synthesized through doping carbon black into hydrothermally synthesized solid-state TiO2 nanowires (NWs) via calcination. The effects of carbon content on the morphology, phase structure, crystal structure, and photocatalytic property under both UV and solar light by the degradation of methylene blue (MB) were explored. Besides, the photoelectrochemical property of C-TiO2 was systematically studied to illustrate the solar light degradation mechanism. After doping with C, TiO2 NWs were reduced into nanorods and the surface became rough with dispersed particles. Results showed that C has successfully entered the TiO2 lattice, resulting in the lattice distortion, reduction of band gap, and the formation of C–Ti–O, which expands TiO2 to solar light activation. Comparing with P25 and anatase TiO2 NWs, doping with carbon black showed much higher UV light and solar light photocatalytic activity. The photocatalytic activity was characterized via the degradation of MB, showing that Kap was 0.0328 min–1 under solar light, while 0.1634 min–1 under UV irradiation. The main free radicals involved in methylene blue degradation are H+ and OH•–. Doping with carbon black led to the reduction of photocurrent in a long-term operation, while C-doping reduced the electron–hole recombination and enhanced the carrier migration.

One of the most effective ways to improve reactive wetting of dual phase (DP) steels during galvanizing process is annealing under relatively high oxygen partial pressure. This annealing process can lead to internal oxide formation rather than external ones. Since these oxides are mostly observed in grain boundaries (GBs), their presence could influence GB-related phenomena such as liquid metal embrittlement (LME) cracking during further manufacturing processes such as resistance spot welding (RSW). The present work has shown that internal oxides located at GBs assisted LME crack formation during RSW of DP steel. Two types of LME cracks were observed in the shoulder and center of the weld. It has been shown that at the initial stages of welding time, LME cracks initiate in the shoulder of the nugget by the Zn diffusion into oxide-bearing GBs. As welding time continues, higher temperatures and tensile stresses are applied to the steel sheets which allow center cracks to be formed more easily due to the presence of oxides which degrade the GBs.

To accurately model the resistance spot welding (RSW) joint in finite element analysis (FEA), the constitutive behavior of materials in various weld regions such as heat-affected zone (HAZ) should be measured. Due to the sharp temperature gradient through RSW specimens, microstructural and corresponding mechanical properties of weld regions are different. Additionally, the size of RSW is small; hence, it is challenging to directly measure the stress–strain curve of materials. In this regard, hardness-scaling and ball-indentation techniques are among the popular methods to in-directly measure the stress–strain curve of these materials. However, the effectiveness of these two techniques on predicting the stress/strain distribution and failure behavior of resistance spot welded advanced high strength steels (AHSS) is not clear. In the present work, the stress–strain curves obtained through hardness-scaling and ball-indentation techniques have been compared. The stress/strain distribution and failure behavior of the resistance spot welded AHSS specimen have been simulated by the stress–strain data obtained using the two methods. The simulation results have been compared with experimental analysis. The results showed that both methods can accurately predict the failure location. With the comparison of FEA results with experiment analysis, it was shown that the ball-indentation method provides slightly better predictions of failure behavior compared to the hardness-scaling method. However, the harness scaling method is a simple and convenient technique, which can be implemented as a qualitative analysis for the failure behavior of RSW joints.

Scripta materialia 206, 114219 (2022). doi:10.1016/j.matdes.2021.109533, In this work, laser welding of a rolled CoCrFeMnNi high entropy alloy to 316 stainless steel was per- formed. Defect-free joints were obtained. The microstructure evolution across the welded joints was as- sessed and rationalized by coupling electron microscopy, high energy synchrotron X-ray diffraction, me- chanical property evaluation, and thermodynamic calculations. The fusion zone microstructure was com- posed of a single FCC phase, and a hardness increase at this location was observed. Such results can be attributed to the formation of a new solid solution (arising from the mixing of the two base materials). Moreover, the incorporation of carbon in the fusion zone upon melting of the stainless steel also aids in the strengthening effect observed. The welded joints presented good mechanical properties, with fracture occurring at the fusion zone. This can be ascribed to the non-favourable, i.e., large grain size, microstruc- ture that developed at this location., Published by Elsevier Science, Amsterdam [u.a.]

Advanced high strength steels (AHSS) used in automotive structural components are commonly protected using zinc coatings. However, the steel/zinc system creates the potential for liquid metal embrittlement (LME) during welding. Recent studies have examined the impact of the welding electrode geometry on LME cracking severity and found there to be some effect, but did not explore the responsible mechanisms for the changes. This work shows that a radius tip electrode provides minimal cracking while a truncated cone shape showed severe LME, particularly in the shoulder region. Thermo-mechanical simulations showed the significance of the thermal contact at the outer region of the electrode/sheet interface (weld shoulder). It was observed that when the water-cooled electrode presses into the steel during the welding, causing a contact between the steel surface and the electrode sidewall, a sudden local cooling of the weld shoulder occurs. This cooling causes contraction and tensile stresses on the material surface, leading to LME. Additionally, the magnitude and location of heat transfer between the steel and electrode is controlled by the thermal contact conductance.

Surface oxide formation from the high alloying contents in advanced high strength steels is detrimental to their Zn coating quality. Selective oxidation by annealing is used in steel production to improve the wettability of Zn to steel surfaces in the continuous hot-dip galvanizing process. Internal (sub-surface) oxides formed in the annealing process suppress surface oxide formation. However, the effect of internal oxides on resistance spot welding has not been thoroughly investigated. In this study, internal oxides were found to cause the weld lobe to shift towards higher welding current by promoting shallow surface melting early in the weld cycle. Molten metal at the contact surface reduces contact resistance and heat input, delaying nugget growth. Dynamic resistance profile and heat input analysis results further confirm the surface melting mechanism in annealed samples.

Advanced high-strength steels (AHSS) used in automotive structural components are commonly protected from corrosion using zinc coatings. However, the steel/zinc system creates the potential for liquid metal embrittlement (LME) during welding. Although adjustments to the welding process have been studied, the present literature has not examined the use of variable input currents for LME reduction. In this work, a ramp down welding current showed LME severity decreased by 60% compared to a standard constant current. Reductions in both crack size and number of cracks were observed for high currents (Imax + 20%). A numerical model of the resistance spot welding process was constructed, which showed when welding with a ramp down welding current, the electrode-to-sheet interface spends less time at an LME-sensitive temperature compared to the standard welding current. Furthermore, it avoids a large jump in tensile stress when the electrodes are removed.

An applied energy density approach defined as the ratio of laser power and scanning velocity is often used as a guideline for selecting appropriate process parameters in laser powder bed fusion (LPBF). In this study, amongst the many variables related to input energy, we investigate the effectiveness of laser energy density (LED) on the melt pool geometry and microstructure of Hastelloy X single tracks produced by fixed LED values at different laser powers and scanning velocities. The results reveal that for a fixed LED, the higher laser power has a higher effect on the melt pool depth. In addition, compared to the scanning velocity, laser power has a higher influence on the melt pool geometry. Moreover, it is proposed that the finer cell structure observed in the melt pool of high laser power is due to the higher cooling rates. Finally, the higher number of new grains observed in melt pools created with higher laser power and fixed LED are likely due to the grain detachment caused by the increase in the partially melted particles.

Nanoporous materials exhibit promising applications in energy storage, catalysis, and sensing. They are typically synthesized by dealloying, a costly and environmentally detrimental technology, valid only within a narrow compositional range of alloys. Surmounting these disadvantages, we assembled nanoporous silver materials via bottom-up nanoscale joining of nanowires, a technique also suitable for other metals. Furthermore, the resulting nanoporous materials exhibit an unprecedented, near-ideal compressive yield strength (∼2.6 GPa). Such an ultra-high strength, however, does not belong to the nanoporous materials composed of nanowires with the minimum length in our samples, challenging the smaller-is-stronger tenet. According to molecular dynamics simulations, such a strength degradation as nanowires shorten is attributed to the internal compressive stress arising from the five-fold twins within nanowires. Such internal stress maximizes at the center and diminishes near free surfaces, making the center part harder to compress than that adjacent to the free surfaces. The volume fraction of the latter increases as the nanowire shortens, diminishing the overall Young's modulus. For nanowires having aspect ratios smaller than six, a reduced Young's modulus lowers the yield strength since the yield strain is independent of aspect ratios. However, if the aspect ratio exceeds six, compression induces bending, reducing both yield strength and yield strain. Overall, this work not only provides new physical insights on the structure-mechanical property relationship for nanoporous silver, but also paves a new way for bottom-up synthesizing nanoporous metals with ultra-high compressive strength efficiently, economically, and environmental-friendly.

Electro-spark deposition (ESD) is a technique whereby material is deposited from the ESD applicator towards a substrate via an electro-spark phenomenon. One potential use for this technique is to repair minor damages on turbine blades made of Ni-based superalloys, such as IN718. To better understand the effect of the processing parameters on the quality of the deposition, in terms of defect formation and the microstructure during the ESD process, a systematic study was carried out. In this work, IN718 deposited using ESD with different pulse energy, achieved by varying the voltage and capacitance, were systematically investigated in terms of its microstructure. It has been observed that increasing pulse energy in the ESD process promotes the formation of defects and inter-metallic phases that may be undesirable in the process of repairing or coating of components. The presence of inter-metallic particles in a certain amount and distribution is believed to increase the susceptibility for cracking of the deposited layers.

Laser welding/brazing of AA5182 Al to ZEK100 Mg in a lap joint configuration was performed by using a Ni interlayer. The stick-out width of Ni interlayer (WNi) had significant effects on the weld a...

Advanced high-strength steels used in automotive structural components are commonly protected using zinc coatings. However, the steel/zinc system creates the potential for liquid metal embrittlement during welding. Although liquid metal embrittlement cracks are known to form, the current literature does not include crack location when assessing crack severity. In this work, TRIP1100 joints showed that LME cracks decreased strength from 7.8 to 42.2%, depending on location, between the coated (cracked) and uncoated (non-cracked) condition. Liquid metal embrittlement cracks in critical locations were observed to propagate until fracture from lap shear testing. However, cracks in non-critically loaded areas were not part of the fracture path and did not result in a significant loss in strength. This shows LME crack location can be controlled to improve joint performance and vehicle safety. In addition, a model of lap shear testing in a cracked sample showed how the presence of a crack can affect the internal stress field depending on its location.

Advancements in additive manufacturing have facilitated its adoption in the aerospace industry, where a lower production volume for high-valued components is required. However, the poor surface quality of additively manufactured parts is detrimental to component lifespan and requires additional post-processing steps. Here, we address surface roughness and near-surface porosities in binder-jet additively manufactured Inconel 625 parts using an electrospark deposition (ESD) technique. Localized surface melting and material transfer from the ESD electrode results in a near-surface region with increased density (from 62.9% to 99.2%) and increased hardness (from 109 HV to 962 HV). The use of an AA4043 aluminum alloy electrode forms a nickel aluminide intermetallic coating when deposited on Inconel 625, with the potential for use in applications that require resistance to high temperature oxidation.

Zinc-coated advanced high-strength steels (AHSS) used in the automotive industry are vulnerable to liquid metal embrittlement (LME) during welding. In this work, a “crack index” is used to link LME crack distributions in resistance spot welds to the weld performance. Other commonly used LME metrics, such as maximum crack length, are unable to predict an effect on weld performance. Because both crack size and location have been established as critical characteristics for loss in weld strength, both of these factors must be taken into account when characterizing LME severity. The crack lengths measured in LME-affected welds were observed to fit a lognormal distribution; therefore, the lognormal median is used as the parameter to account for crack size. Long cracks are more likely to adversely impact mechanical performance. Number of cracks can be used to account for the probability that a crack will be found in a critical location. These parameters are multiplied together and divided by the sheet thickness to produce the crack index. A large crack indicates that LME cracks in the weld are likely to impact the mechanical performance of the weld. A simpler version of the crack index may be calculated using the normal median.

In this work, we report for the first time the electrochemical oxidation as a technique to improve the electrical performances of carbon-based resistive switching devices. The devices obtained through the anodic oxidation of carbon-structures possess superior electrical performances i.e. a 3-level memory behavior and an ON/OFF ratio two order of magnitude higher than the non-oxidized carbon-based devices. It is demonstrated that the chemical composition of the carbon structures (i.e. percentage of oxygen groups, sp2 and sp3 carbon atoms) plays a key role in the improvement of the carbon-based devices. The electrochemical oxidation allows the possibility to control the oxidation degree, and therefore, to tailor the devices electrical performances. We demonstrated that the resistive switching behavior in the electrochemically oxidized devices is originated from the formation of conductive filament paths, which are built from the oxygen vacancies and structural defects of the anodic oxidized carbon materials. The novelty of this work relies on the anodic oxidation as a time- and cost-effective technique that can be employed for the engineering and improvement of the electrical performances of next generation carbon-based resistive switching devices.

In this study, we evaluated the effectiveness of UV-LED-irradiated TiO2 in removing 24 commonly detected PPCPs in two water matrices (municipal wastewater effluent and Suwannee River NOM–synthetic water) and compared their performance with that of ultrapure water. Relatively fast removal kinetics were observed for 29% and 12% of the PPCPs in ultrapure water and synthetic surface water, respectively (kapp of 1–2 min−1). However, they all remained recalcitrant to photocatalysis when using wastewater effluent as the background matrix (kapp &lt, 0.1 min−1). We also observed that the pH-corrected octanol/water partition coefficient (log Dow) correlated well with PPCP degradation rate constants in ultrapure water, whereas molecular weight was strongly associated with the rate constants in both synthetic surface water and wastewater. The electrical energy per order (EEO) values calculated at the end of the experiments suggest that UV-LED/P25 can be an energy-efficient method for water treatment applications (2.96, 4.77, and 16.36 kW h m−3 in ultrapure water, synthetic surface water, and wastewater effluents, respectively). Although TiO2 photocatalysis is a promising approach in removing PPCPs, our results indicate that additional challenges need to be overcome for PPCPs in more complex water matrices, including an assessment of photocatalytic removal under different background water matrices.

International audience; Polycrystalline Ni0.05Mo3Sb5.4Te1.6 thermoelectric (TE) material samples were mixed with NiSb nanoparticles (60–80 nm) in 0, 0.034, 0.074 and 0.16 vol fractions, then hot-pressed and their TE transport properties were characterized. There was a gradual increase in electrical conductivity with the addition of NiSb nanoparticles. The electrical conductivity (σ) of the 0.16 sample was increased by 163% compared to the NiSb-free sample. Except for the 0.16 sample, all samples showed alloy scattering (σ ~ T−0.5). With an increase in NiSb content, the Fermi energy appeared to be reduced, getting closer to the valence band edge. For all samples, the variation in lattice thermal conductivity with temperature (κl ~ T−0.27) was very similar, indicating that the mode of phonon scattering was the same in all samples.

This study reports the concept of a water/moisture-induced hygroelectric generator based on the direct contact between magnesium (Mg) alloy and oxidized carbon nanofibers (CNFs). This device generates an open-circuit voltage up to 2.65 V within only 10 ms when the unit is placed in contact with liquid water, which is higher than the reduction potential of magnesium. The average peak short-circuit current density is ∼6 mA/cm

Third-generation advanced high strength steels are typically given a zinc coating that provides excellent resistance to corrosion. During the resistance spot welding process, the melted zinc coating enables liquid metal embrittlement (LME) that causes cracking in the weld indent. In this study, LME in TRIP 1100 and TRIP 1200 steels was suppressed by placing aluminium interlayers added between the electrode and steel contact surface. Compared to welds exhibiting LME, TRIP 1100 with aluminium interlayers showed complete strength recovery while TRIP 1200 with aluminium interlayers resulted in a recovery of strength by 90%. Aluminium interlayers suppress LME by the formation of iron aluminides that hinder liquid zinc from coming in contact with the steel substrate, thus preventing LME.

A 2D C/C composite with a high porosity (low strength) and a 3D C/C composite with a low porosity (high strength) were investigated for dissimilar joining to Ti6Al4V via reactive spot welding. It was determined that infiltration of melted metal into the composite and formation of a continuous thin TiC layer at the interface of the joints were the dominant joining mechanisms. The 2D C/C composite with a flat surface was successfully joined to Ti6Al4V due to the infiltration of the melted Ti6Al4V into its porous content. On the other hand, it was necessary to drill rectangular grooves onto the surface of the 3D C/C composite to facilitate the infiltration of the melted Ti into the composite, which produced high-strength joints. Surface patterning was determined to be necessary to join the components with mismatching coefficients of thermal expansion. The strength of the 2D C/C composite and Ti6Al4V joints was found to be 7 MPa, while the maximum strength of the groove-patterned 3D C/C composite and Ti6Al4V joints reached 46 MPa.

Liquid metal embrittlement (LME) is one of the severe problems of Zn-coated steel in resistance spot welding (RSW). Hence, proper welding schedules for Zn-coated steel are of practical interest. RSW involves a complex interaction between electrical, thermal, and mechanical phenomena. Identification and integration of all these governing physics are almost impossible by performing simple experiments. Hence, phenomenological modeling of RSW has gained a significant attention in the recent past. The complexity of the physical process introduced by the dynamic nature of contact resistance brings challenges for the model. A simplified but effective modeling approach of RSW is proposed where attention is focused on the evaluation of the thermal field using the finite element (FE) method. The interaction of the mechanical and electrical field is performed by the dynamic variation of the contact area, stress concentration, and non-uniform current density distribution in a semi-analytical model. These internal variables of the model are incorporated through the scaling of the governing parameters by the dependence of the transient and converged temperature field within a time step. The transient-dynamic contact resistance is detached from the measurement of total resistance and mapped adaptively by the implicit scheme within a time step of the numerical model. The transient development of the nugget is investigated for dual-phase steel (DP980) with an interrupted test of the dynamic resistance curve. The FE model is validated with experimentally measured results at different process conditions. The characterization of the thermal history from the model relatively identifies the LME phenomena and suggests corresponding modification of the welding schedule.

Polypyrrole (PPy) is a conductive polymer that can be fabricated into various structures via in-situ polymerization for different applications. However, a kinetics study of its in-situ polymerization is needed for a better understanding of the mechanisms of pyrrole polymerization. This paper develops two different kinetics models based on existing PPy polymerization mechanisms. The most suitable mechanism is first identified by comparing the model results with experimental data. Then, in-situ polymerizations of PPy on electrospun fibrous polyacrylonitrile (PAN) templates were produced at temperatures ranging from 273 to 285 K. The results show that the overall reaction rate of the in-situ polymerization process in the presence of electrospun fibrous template is faster than that without the template. Further investigation confirms that the increase in the overall reaction rate is attributed to the enhanced reactions between oxidized pyrrole oligomers and neutral pyrrole monomers, as the corresponding reaction rate constant and activation entropy increased by 158.2-209.6% and 37.7%, respectively. The reason is that the considerable number of available reaction sites between oxidized oligomers and neutral monomers are created by the fibrous template. In addition, the composite membrane obtained from the in-situ polymerization exhibited well-developed fibrous nanostructure, good electrical conductivity (0.29 ± 0.04 S∙m-1), sufficient mechanical strength (UTS of 8.7 MPa) and relatively stable thermal properties (up to 250°C).

Simplifying the manufacturing of metal matrix composites (MMCs) will allow for their wider use in applications that require lower density, higher strength, and high wear resistance when compared to traditional metals. An in-situ method of MMC formation is proposed, using a binder jet additive manufacturing (BJ-AM) process with only Inconel 625 powder and a carbon-containing binder. Carbide formation occurs at elevated temperatures during sintering by combining Cr, Mo and Nb alloying elements in Inconel 625 and carbon from the binder. The core-shell morphology and composition of the final MMC is tuned by controlling the quantity of carbon in the system during the sintering step.

The degradation of high-temperature components in the aerospace industry becomes a greater concern with the use of higher operating temperatures and increased operating cycles. Although the repair of defects can extend component lifespans, welding often results in a heat-affected zone (HAZ) or fusion zone with reduced mechanical properties. Due to the low energy input of electrospark deposition (ESD), repaired components should be less susceptible to mechanical property deterioration. ESD of alloy 718 on solution-annealed and aged alloy 718 base metal is evaluated in the as-deposited and direct-aged condition. HAZ formation is measured at 80 µm on an annealed substrate and 40 µm on an aged substrate. Direct aging of depositions eliminates the heat-affected zone and introduces strengthening phases in the deposition that results in a hardness equivalent to that of the aged base metal. The yield strength of as-deposited and direct-aged alloy 718 depositions is equivalent to the annealed and aged base metal, respectively, whereas the ultimate strength is, respectively, 16 and 8 pct lower. Decreased ultimate strength is attributed to lower fracture toughness of brittle secondary phases and splat boundaries from the ESD process that remain after the direct aging heat treatment.