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This research assesses the thermophysical and ultrasonic characteristics of the intermetallic compound Ni3Ti, which has a hexagonal crystalline structure. The selected material exhibits many noteworthy characteristics, including the shape memory effect, a high melting point, extremely elastic qualities, etc. The Lennard-Jones potential model has been used to calculate the higher-order elastic constants. The mechanical properties of the material, which provide details regarding its stability and intrinsic qualities, are computed using the second-order elastic constants. Additionally, we have computed the thermal conductivity at 300 K, specific heat, ultrasonic velocities, and Debye temperature. Ultimately, the ultrasonic attenuation is determined using all of the available parameters. The obtained results agree with the data available in the literature. [ABSTRACT FROM AUTHOR]

In the current study, conventional and underwater friction stir welded aluminum–magnesium joints to decrease heat input and control the formation and morphological properties of brittle intermetallic compounds (IMC) were investigated. The joining was incorporated by Zn interlayer and TiC nanoparticles to the interface of joints by providing a novel groove design on the adjacent side of magnesium to hinder nanoparticle dissipation during the welding process. The implemented rotation speeds were varied within 850–950 rpm under a constant traverse speed of 45 mm/min to achieve optimized joining parameters and sound joints with acceptable metallurgical bonding and mechanical interlocking. It was found that the changing of heat input plays the most significant effect on microstructure evolution, wettability, nanoparticle distribution, and IMC formation (Al3Mg2 and Al12Mg17). The joined sample produced at 950 rpm and 45 mm/min underwater friction stir welding (UWFSW) process reached the best microstructure evolution and mechanical properties. It was shown that the TiC particles play a significant role in the microstructure modification and enhanced mechanical properties of weld samples while the Zn foil interlayer plays a vital on avoiding the formation of Al-Mg IMC phases. Mg-Zn and Mg-Al-Zn IMCs, residual Zn, Al and Mg solid solution were observed as the most common phases in the boarded interfaces instead of the formation of the hard and brittle Al-Mg IMCs. The refinement microstructure, presence of thin IMCs, uniform distribution of nanoparticles, and controlled heat input in the stir zone (SZ) were shown as the fundamental reasons for a noticeable improvement in the mechanical properties of dissimilar weld samples by UWFSW. Also, brittle fracture mode was detected for most joint samples, while relative ductile fracture mode was also observed. [ABSTRACT FROM AUTHOR]

There has been significant interest in developing new catalytic systems to convert linear chain alkanes into olefins and aromatics. In the case of higher alkanes (≥C6), the production of aromatic compounds such as benzene‐toluene‐xylenes is highly desirable. However, as the length of the carbon chain increases, the dehydrogenation process becomes more complex, not only due to the challenges of C−H activation but also the need for selectivity towards the desired products by the possibility of side reactions such as isomerization and cracking. Here, we present a detailed analysis of the dehydroaromatization of n‐hexane, n‐heptane, and n‐octane, using PtSn intermetallic nanoparticles supported on SBA‐15 as the catalyst. Through in situ spectroscopic and kinetic analysis, we have probed the reaction kinetics and catalyst deactivation, and provided a mechanistic understanding of the dehydroaromatization process on the surface of the PtSn intermetallic nanoparticles. Introducing Sn has been shown to be crucial not only for enhancement of catalytic activity, but also for higher aromatics selectivity and stability on stream. Furthermore, the analysis of dehydroaromatization reaction rates of reactant and possible intermediates indicates that the dehydroaromatization of n‐hexane to benzene likely proceeds through initial dehydrogenation steps followed by ring closing. [ABSTRACT FROM AUTHOR]

The two-way shape memory effect with reversible compressive strain up to 5.1% and high cyclic stability is obtained for Ni44Fe19Ga27Co10 (at.%) single crystals by stress-induced martensite aging at 398 K for 1–3 h, under 650 MPa. 100 cycles of thermal treatment at temperatures not exceeding aging temperature, do not affect the temperature of the martensite formation, and reversible strain reduces merely by 0.4%. Thermal cycling with aging overheating significantly decreases reversible strain down to 1% due to the austenite stabilization. [ABSTRACT FROM AUTHOR]

The random forest (RF) algorithm is considered as a powerful statistical classifier that is more popular in other fields but is relatively unknown in HEA(s)’s prediction phase. In this research, Random Forest (RF) technique is used to investigate phase selection principles effectively utilizing a large experimental case study on 401 distinct HEAs, comprising 174 SS , 54 IM , and 173 S S + I M phases. The accuracy of the proposed method is almost 10% higher than SVM and KNN for classifying HEA(s). Moreover, the precision of the proposed method is similar to ANN. Experimental results indicate the validity and reliability of the RF-based diagnosis method. [ABSTRACT FROM AUTHOR]

A lightweight multi-material combination of steel and aluminium alloy is becoming a novel approach towards environmentally sustainable transport systems. However, the joining of steel/Al is difficult due to the formation of brittle and hard intermetallic compounds (IMC) at the interface. Hence, there is an immense need to critically review the metallurgical challenges of IMC formation for steel/Al dissimilar RSW and summarise its significance and current scenario for controlling IMC formation and growth. This article presents the review of past research works that focus on controlling the formation and growth of IMC for steel/Al dissimilar resistance spot welding during the last decade. It also includes IMC formation mechanism, advanced characterisation techniques, significance of IMC thickness and effect of process parameters on IMC formation. Fe2Al5 is the most brittle and dominant IMC formed at the interface, which affects the soundness of the welded joint. Application of third-party interlayer at the interface, directly or by an auxiliary process, is observed as an effective approach for controlling the growth of IMC. Though this interlayer does not prevent the formation of IMC, it will reduce the growth or brittleness of IMC by changing its chemical configuration. [ABSTRACT FROM AUTHOR]

Additive manufacturing (3D printing) is one of the most promising methods for creating complex metal parts and structures. It has already become a widespread industrial method in the production of coatings or various details of constructions and mechanisms made of pure metals and alloys. In this work, the mechanisms of the formation of intermetallic compounds based on nickel, aluminum and chromium by a dual-wire electron beam additive manufacturing were studied. The microstructure, phase composition, and microhardness of the intermetallic material strongly depend on the ratio of NiCr and Al wires deposited during the electron-beam melting. The intermetallic material based on the NiAl phase was obtained by the deposition of wires in the equal ratio NiCr:Al = 1:1. In the material obtained with a wire ratio of NiCr:Al = 3:1, ordered Ni3Al(Cr) and disordered Ni3Cr(Al) intermetallic compounds are predominantly observed, but the fraction of the Ni3Cr-based phase prevails. The microhardness of the NiAl-based alloy turns out to be higher (5.1 GPa) than that of the Ni3Al(Cr)-based material (4.3 GPa). These intermetallic alloys are developed for the production of intermetallic coatings using electron beam additive manufacturing method. [ABSTRACT FROM AUTHOR]

γ-TiAlNb intermetallic compound is a highly promising material for aircraft structural components. A 46Ti-46Al-8Nb intermetallic compound was prepared and subjected to three different heat treatments. The changes in phase composition, microstructure, and hardness of the as-cast samples and heat-treated samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and Rockwell hardness. Subsequently, the material was designed for milling of thin-wall structures, with a focus on side milling. The milling process was investigated under different axial and radial cutting depths, and the variations in multi-directional cutting forces were analyzed, taking into consideration the surface quality of the machined parts. The results indicate that the γ-TiAlNb intermetallic compound possesses high hardness and brittleness. With increasing heat treatment temperature, the content of TiAl phase significantly decreases, while the content of AlTi3 phase increases notably. The β-Ti phase containing Nb remains nearly unchanged and is mainly located at grain boundaries. Heat treatment can enhance the machinability of the TiAlNb intermetallic compound. A heat treatment process involving a 1-hour hold at 1200 °C followed by furnace cooling results in reduced Rockwell hardness, lower milling forces in three directions and improved surface quality. [ABSTRACT FROM AUTHOR]

Maraging steels achieve the highest strength limit when aged around 480 °C. Some research has been carried out on this treatment at temperatures different from 480 °C to improve the toughness and magnetic properties of this metal. This research uses Mössbauer spectroscopy, X‐ray diffraction (XRD), hardness measurements, and transmission electron microscopy (TEM) to investigate the phase transformation process of solution‐treated Maraging‐300 steel specimens aged at 520, 560, and 600 °C. The results indicate that the precipitation of intermetallic compounds, which are responsible for the improvement of mechanical properties, occurs similarly to precipitation at the temperature of 480 °C within the first hour of ageing. The coexistence of precipitates and the austenitic phase is detected, and a crystalline/magnetic transition zone is suggested in the material for longer times and higher ageing temperatures. [ABSTRACT FROM AUTHOR]

Intermetallic compounds (IMCs) have attracted significant attention in recent years due to their unique properties and potential applications in various fields, particularly in catalysis. This review aims to provide an in-depth understanding of IMCs, including their synthesis methods, structural characteristics, and diverse catalytic applications. The review begins with an introduction to IMCs, highlighting their distinct features and advantages over traditional catalyst materials. It then delves into the synthesis techniques employed to prepare IMCs and explores their structural properties. Subsequently, catalytic applications of the IMCs are introduced, focusing on the key reactions and highlighting their superior catalytic performance compared to conventional catalysts. Future perspectives for, and challenges to, the catalysis of IMCs are then proposed. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The alloys of the Ti–Zr–Mn system based on the C14-type Laves phase are considered as ones of the most promising materials for safe storage and transportation of hydrogen. These alloys have appropriate parameters for activating the processes of absorption and release of hydrogen, a low cost, and a fairly high cyclic stability. In this work, the microstructure and phase composition of the starting alloys and the crystal structure of the hydrides synthesized from them are studied. Possible ways to reduce the cost of the final products are shown. The fact that changing the method of the alloy fabrication does not significantly affect its hydrogen absorption properties is shown. On the example of the considered alloys, it is shown that, as expected, alloying with an element with a larger atomic radius that forms a stable chemical compound with hydrogen results in an increase in the hydrogen capacity. This is explained by both the increased radius of the tetrahedral interstitial sites, where hydrogen atoms are located after dissolution, and the higher total amount of the element interacting with hydrogen.

Evolution mechanism of interfacial multi-layer intermetallic compounds (IMCs) and their impact on failure behavior in Al–Au wire bonding after thermal storage and thermal cycle process are investigated. Microstructural analysis shows that multi-layer IMCs form between the Al wire and barrier layer. After thermal storage and thermal cycle process, the Au8Al3 layer transforms into AuAl2, and Au pad transforms to a thicker layer containing Au2Al and AuAl. Thermodynamic analysis indicates that Au8Al3, Au2Al, AuAl, and AuAl2 have increasing stability. Small-size, equiaxed AuAl2 grains form due to high stored energy, while large-size, columnar Au2Al and AuAl grains result from slower reaction rate and limited recrystallization. The stack-like formation of AuAl2 grains is attributed to the balance between driving force and interfacial energy resistance. During thermal storage, thicker IMC layers cause cracking between IMC layers and Au pad, and micro voids form near the IMC layers/barrier layer interface due to Kirkendall effect. Thermal stress results show that plastic deformation of the Al layer slightly affects the thermal stress in other layers during the thermal cycle process. The cyclic stress at the interface with initial cracks ranges from −157 MPa to 114 MPa, facilitating crack propagation. Additionally, micro void grows under cyclic thermal input, weakening interface adhesion. Therefore, bond strength decreases and frequency of bonding lift-off with cracking along the IMC layers/barrier layer interface increases after thermal storage and thermal cycle process. These results provide the guidance for regulating the interfacial IMCs and predicting the thermal stress in Al–Au wire bonding.

Cu pillar bump (CPB) technology as the representative advanced packaging technology possesses the characteristics of miniaturization and high density, thus playing an important role in the reliability of electronic devices. However, the brittle intermetallic compound (IMC) layer in the joints evidently affects the service performance and reliability of CPB joints. Thus, the influence of IMC layer thickness and microstructure needs to be carefully evaluated. In this study, the reliability of CPB joints with different IMC layer thickness under the condition of isothermal storage and room-temperature electromigration was tested, and the effect of initial IMC thickness of joints on the reliability was revealed. The full-IMC joints have the best isothermal storage reliability while the half-IMC joints perform the worst. Meanwhile, the thin-IMC joints own the best electromigration reliability but the full-IMC joints show the worst because that the initial voids in full-IMC joints accelerate the failure caused by electromigration.

Due to the demand for high-performance electronic products, there has been a rapid development in three-dimensional integrated circuit (3D IC) packaging technology. The 3D stacking relies on microbumps and through silicon vias (TSVs) to connect multiple Si dies vertically. These high-performance electronic products usually need to consume high power, combined with limited heat dissipation due to dense packing, resulting in the issue of Joule heating. The problem of Joule heating impacts the reliability of products. This study investigated the factors contributing to Joule heating of microbumps and its subsequent reliability issues through experimental methods and finite element analysis (FEA) simulations. Joule heating was quantified by measuring the temperature increase at stable states using the temperature coefficient of resistance (TCR) equation. We first observed that environmental temperature influences Joule heating. Higher oven temperature can exacerbate the Joule heating effect and lead to higher temperature increase under the same current density. We also examined the effect of intermetallic compound (IMC) formation on Joule heating, with a 12.5% increase in heat generation after IMC formation. Furthermore, the adverse effect of voids induced by sidewall wetting during high-temperature storage (HTS) on Joule heating using FEA was demonstrated. Additionally, we discovered severe Joule heating to cause thermomigration (TM) in the microbumps at a system level. Finally, we proposed structural optimization of the microbump to mitigate Joule heating and enhance reliability.

The microstructure details of the interface, mechanical properties and failure mechanism of laser welding-brazing (LWB) steel-Al joints with various welding parameters were comparatively investigated. The emergence of ternary Fe–Al–Si intermetallic compounds (IMCs) was observed in the interfacial area of the joints prepared utilizing ER4047 filler. In contrast, only the binary Fe–Al IMCs were formed in the interfacial area of the joints prepared employing ER5356 filler. With the same laser tilt angle, the IMCs layer of the joints prepared with ER4047 was thinner than that of the joints prepared with ER5356, implying the rapid growth of the IMCs welded via the ER5356 filler. The tensile strength exhibited by the former surpassed that of the latter. Employing the same filler metal, the average thickness of the IMCs layer of the joints with laser tilt angle of 10° was smaller than that of the joints with laser tilt angle of 20°. The strength of the joints with smaller tilt angle was better than that of the ones with bigger tilt angle. The tensile test outcomes revealed that there existed failure competition among the Al alloy base metal (Al-BM), weld metal (WM) and interface structure. If the interface structure was Fe–Al IMC with high brittleness, the cracks propagated along the interface, and finally fractured at the interface. If the interface structure was Fe–Al–Si IMC with good toughness, the crack propagation in the interface region could be hampered. In this case, the joint was prone to occur via WM failure or even Al-BM failure modes.

Effects of Si and Mg as main elements on interface reaction between tool steel and molten Al alloy at 700°C were investigated. Pure aluminum and Al-10mass%Mg alloy showed relatively simple interfacial layers, whereas thicker, multi-layered reaction bonds were found in the diffusion couple of A380 alloy. The diffusion of a large amount of Fe into Al matrix throughout the interfacial layer led to the formation of Al-Fe based intermetallic particles in the Al base metals. The diffusion couple of Al-10mass%Mg alloy showed a similar intermetallic layer as that of pure Al, indicating that 10mass%Mg in the Al melt rarely affected the formation of Al-Fe intermetallic layers. However, A380 alloy showed much expanded soldering area and increased thickness of intermetallic layers. Based on the phase diagram calculated, the solubility of Fe in liquid Al increased significantly with increasing Si content up to apploximately 5mass%, while, in the case of 10mass%Mg addition, the Fe solubility gradually decreased with increasing Mg content. Al-10mass%Mg alloy also showed the same tendency as that of pure Al in the formation and distribution of intermetallic compounds. However, in the Al-12mass%Si alloy, two types of Al-Fe-Si ternary compounds are present on the Al-rich side.

This study investigates the microstructural evolution and growth behavior of intermetallic compound (IMC) layers in the Cu/(Sn-yAg, y = 0.29–2.00 wt%) system during isothermal aging within the temperature range of 433–473 K. Through systematic variations in Ag content, aging temperature, and time, the fundamental mechanisms governing IMC formation and growth in Cu/(Sn–Ag) solder joints are elucidated. The results demonstrate that IMC growth kinetics follow a power-law relationship, with IMC layer thickness increasing systematically with annealing time. The addition of Ag significantly influences IMC nucleation and growth, with higher Ag content correlating with faster growth rates. Furthermore, the temperature dependence of IMC growth rates is investigated, revealing higher temperatures leading to increased growth rates, indicative of boundary diffusion-controlled growth. By calculating activation enthalpies, values of 36.4 kJ/mol for Sn-2.00Ag and 30.2 kJ/mol for Sn-0.50Ag were obtained, providing quantitative insights into the faster growth rate of intermetallic compound thickness in the Cu/(Sn-2.00Ag) diffusion couple within the experimental temperature range. These findings offer valuable insights into factors affecting the reliability and performance of solder joints in electronic packaging applications.

The primary issue with joining an immiscible magnesium/iron system is the lack of a bonding medium. This research used an aluminium (Al) additive as a bonding medium to facilitate the formation of an interface layer. Immiscible AZ31 magnesium alloy and SPHC low-carbon steel were successfully joined by employing aluminium (Al) powder as an additive in the gap between them with friction stir welding (FSW). The extensive interfacial microstructural analyses confirmed that the aluminium-rich Fe2Al5 intermetallic compound (IMC) formed with a range of 20–25 nm in thickness at the interface between magnesium and iron resulted from the metallurgical reaction between the Al powder additive and base SPHC steel. This IMC phase served as a transitional layer, facilitating the metallurgical bonding between Magnesium and Iron. The tensile strength of the joint was significantly improved by 43%, from 126 MPa without the additive to 180 MPa using the aluminium additive. The formation of the following well-matched interface lattice sites between Fe and Fe2Al5 region was identified: (002)Fe2Al5//(110)Fe, [110]Fe2Al5//[1‾ 13]Fe. The intermetallic Fe2Al5 was composed of nanocrystalline and amorphous interface layers. Furthermore, the fracture of the joint occurred at the interface, indicating a brittle mode of fracture behaviour.

In this study, we investigated the brittle fracture behavior of Sn-3.0Ag-0.5Cu (SAC305) solder joints with a Direct Electroless Gold (DEG) surface finish, formed using laser-assisted bonding (LAB) and mass reflow (MR) techniques. Commercial SAC305 solder balls were used to ensure consistency. LAB increases void fractions and coarsens the primary β-Sn phase with higher laser power, resulting in a larger eutectic network area fraction. In contrast, MR produces solder joints with minimal voids and a thicker intermetallic compound (IMC) layer. LAB-formed joints exhibit higher high-speed shear strength and lower brittle fracture rates compared to MR. The key factor in the reduced brittle fracture in LAB joints is the thinner IMC layer at the joint interface. This study highlights the potential of LAB in enhancing the mechanical reliability of solder joints in advanced electronic packaging applications. [ABSTRACT FROM AUTHOR]

Bi-doped Sn–Ag–Cu (SAC) microelectronic solder is gaining attention for its utility as a material for solder joints that connect substrates to printed circuit boards (PCB) in future advanced packages, as Bi-doped SAC is reported to have a lower melting temperature, higher strength, higher wettability on conducting pads, and lower intermetallic compound (IMC) formation at the solder-pad interface. As solder joints are subjected to aging during their service life, an investigation of aging-induced changes in the microstructure and mechanical properties of the solder alloy is needed before its wider acceptance in advanced packages. This study focuses on the effects of 1 to 3 wt.% Bi doping in an Sn–3.0Ag–0.5Cu (SAC305) solder alloy on aging-induced changes in hardness and creep resistance for samples prepared by high cooling rates (>5 °C/s). The specimens were aged at ambient and elevated temperatures for up to 90 days and subjected to quasistatic nanoindentation to determine hardness and nanoscale dynamic nanoindentation to determine creep behavior. The microstructural evolution was investigated with a scanning electron microscope in tandem with energy-dispersive spectroscopy to correlate with aging-induced property changes. The hardness and creep strength of the samples were found to increase as the Bi content increased. Moreover, the hardness and creep strength of the 0–1 wt.% Bi-doped SAC305 was significantly reduced with aging, while that of the 2–3 wt.% Bi-doped SAC305 increased with aging. The changes in these properties with aging were correlated to the interplay of multiple hardening and softening mechanisms. In particular, for 2–3 wt.% Bi, the enhanced performance was attributed to the potential formation of additional Ag3Sn IMCs with aging due to non-equilibrium solidification and the more uniform distribution of Bi precipitates. The observations that 2–3 wt.% Bi enhances the hardness and creep strength of the SAC305 alloy with isothermal aging to mitigate reliability risks is relevant for solder samples prepared using high cooling rates. [ABSTRACT FROM AUTHOR]

TiAl-based alloys represent a novel class of lightweight, high-temperature structural materials that exhibit exceptional properties, including low densities, high specific strength, and remarkable thermal resistance. These properties make them exceedingly promising for supplanting nickel-based superalloy in the production of pivotal components for aerospace, marine, and automotive engines. Regrettably, like most intermetallic compounds, TiAl-based alloys are subject to certain shortcomings, such as room-temperature brittleness, deformation difficulties, and susceptibility to cracking, which present challenges for shaping these materials into intricate forms using traditional processing methods. In this regard, additive manufacturing (AM), with its high processing freedom and energy, has emerged as a revolutionary technology for the fabrication of complex structural components of TiAl-based alloys. However, AM TiAl-based alloys are still plagued by issues such as cracking, porosity, and uneven microstructure. Therefore, various post-processing techniques were employed to tune the microstructure, and thus enhance the performance of AM TiAl-based alloys. This paper reviews the research progress of AM TiAl-based alloys, summarizing the effects of process parameters, alloying, heat treatment, and surface treatment on the microstructure and mechanical properties of these alloys. Additionally, it discusses the challenges and prospects for the future development of AM TiAl-based alloys. [ABSTRACT FROM AUTHOR]

The electronic packaging industry is gradually moving away from lead solder to lead-free solder, which is more environmentally friendly. However, there is still work to be done to ensure that lead-free solder meets the demands and requirements of the latest technology. The present study demonstrates the analysis of the microstructure formation of Cu6Sn5 and Cu3Sn intermetallic compound layers in Sn-10Cu/Cu solder joints. Therefore, the key objective of this research is to determine the growth rate and activation energy of the Cu6Sn5 and Cu3Sn intermetallic compound layer of the Sn-10Cu/Cu solder joint. The investigation on the bulk solder microstructure which consists of Cu6Sn5 and Cu3Sn intermetallic compound layer was carried out using Optical Microscope (OM), Scanning Electron Microscope (SEM) with EDX and ImageJ software. The IMC layer undergoes rapid growth with increasing aging temperature and duration and the two main IMC layers (Cu6Sn5 and Cu3Sn) grew thicker. The growth kinetic solder joints for Sn-10Cu and Sn-0.7Cu are 22.44 kJ/mol and 31.20 kJ/mol, respectively. Hence, the findings from this study may offer useful information for the development of high-reliability solder joints in future applications. [ABSTRACT FROM AUTHOR]

The alloys of the Ti-Zr-Mn system based on the C14-type Laves phase are considered as ones of the most promising materials for safe storage and transportation of hydrogen. These alloys have appropriate parameters for activating the processes of absorption and release of hydrogen, a low cost, and a fairly high cyclic stability. In this work, the microstructure and phase composition of the starting alloys and the crystal structure of the hydrides synthesized from them are studied. Possible ways to reduce the cost of the final products are shown. The fact that changing the method of the alloy fabrication does not significantly affect its hydrogen absorption properties is shown. On the example of the considered alloys, it is shown that, as expected, alloying with an element with a larger atomic radius that forms a stable chemical compound with hydrogen results in an increase in the hydrogen capacity. This is explained by both the increased radius of the tetrahedral interstitial sites, where hydrogen atoms are located after dissolution, and the higher total amount of the element interacting with hydrogen. [ABSTRACT FROM AUTHOR]

The advancement of renewable energy is intricately relied on the development of diverse sustainable electrochemical devices. Persuing exceptionally efficient multifunctional electrocatalysts is imperative, as it promises to significantly streamline the electrode fabrication process, thereby enhancing the overall effectiveness of these devices. Herein, a trifunctional electrocatalysts of N‐doped carbon (NC) supported intermetallic PtZn catalyst (PtZn‐IMC@NC) are reported, which performs highly attractively toward the electrocatalysis of glycerol oxidation reactions (GOR), oxygen reduction reactions (ORR), and hydrogen evolution reactions (HER). Its effectiveness are demonstrated as electrocatalysts for both the anode and cathode in a hybrid acid/alkali direct glycerol fuel cell (AA‐DGFC) and a hybrid acid/alkali glycerol‐hydrogen electrolyzer (AA‐GHEC). The AA‐DGFC can release an impressive peak power density of 286.8 mW cm−2, while the AA‐GHEC achieves a noteworthy current density of 100 mA cm−2 at a significantly low applied voltage of 0.47 V. Such intermetallic PtZn‐based trifunctional electrocatalyst empowers them to establish a self‐powered integrated electrochemical device with the AA‐DGFC driving the AA‐GHEC. This setup exemplifies efficient valorization of glycerol into formate in both cells and hydrogen production in electrolyzer device. This study sparks innovation across diverse applications of multifunctional electrocatalysts and infuses renewed momentum into the realm of advanced energy devices. [ABSTRACT FROM AUTHOR]

In the present investigation, an effort has been made to join commercial pure titanium and stainless steel 304L by plasma-assisted heating techniques. The diffusion bonding is conducted at 750 °C with varying heating rates viz. 100, 150, 200, 250 °C/min with holding for 5 minutes with varying pressure condition (44 MPa). The bonding strength of the interfacial region is evaluated by the tensile test. The result shows that the diffusion of Fe in Ti leads to the formation and stabilization of Fe2Ti in the interfacial zone. To understand the effect of varying holding time and heating rate, the bond width is studied using optical and scanning electron microscopes. It is observed that the thickness of the joint is reduced by increasing the heating rate. This leads to maximum bonding strength 418 MPa for the bond made at 150 °C/min withholding the pressure to room temperature whereas the bonding strength falls to 340 MPa at 200 °C/min due to the formation of a thick brittle intermetallic compound. [ABSTRACT FROM AUTHOR]

Anode‐free potassium (K) metal batteries are promising candidates in high‐energy‐density batteries. Nevertheless, the notorious potassium dendrite growth and poor K plating/stripping efficiency originating from the potassiophobicity of conventional Cu current collectors impede their practical applications. Herein, by means of systematically multi‐scale theoretical simulations, the correlations among K deposition morphology, nucleation sites, and potassiophilicity of mediation layers are well illuminated from thermodynamics and dynamics perspectives. As a proof of concept, a potassiophilic alloy Cu6Sn5 layer is constructed on commercial Cu foils via a facile electroless plating approach. The designed Cu6Sn5@Cu can guide the homogeneous distribution of K+ flux and regulate the electronic field, promoting uniform K+ plating and stripping. Meanwhile, a KF‐rich solid electrolyte interphase (SEI) layer with high mechanical strength is electrochemically induced and formed, facilitating the transport of K+ through SEI and enhancing the stability of SEI. Consequently, Cu6Sn5@Cu delivers great performance with durable stability of up to 600 h (1 mA cm−2 and 1 mAh cm−2) in no‐reservoir half‐cells. Benefiting from the unique mediation layer design, a novel anode‐free K‐metal full‐cell prototype demonstrates ameliorative cyclic stability. This work advances a fundamental understanding and establishes the bridge between the potassium deposition morphology and mediation layer properties for anode‐free potassium‐metal batteries. [ABSTRACT FROM AUTHOR]

Reductions in automobile weight and carbon dioxide emission are critical for the further development of the automobile industry. Aluminum is a lightweight material that can replace copper in automobile electronic equipment; therefore, laser welding of aluminum and copper is a subject of extensive research. This study investigates the influence of the laser strategy on the laser welding of aluminum and copper while preventing the formation of brittle Al–Cu intermetallic compounds. Aluminum and copper plates with a length of 20 mm and thickness of 0.3 and 1 mm, respectively, are used for the experiment. A continuous-wave laser with a power of 500 W and a spot beam radius of 150 μm is employed to irradiate the aluminum surface at different scan speeds. An electroless-plated nickel layer is used as a buffer between aluminum and copper, and the experimental results show that it can prevent copper surface damage and the formation of Al–Cu compounds during laser welding. In addition, the simulation and experimental results reveal that the residual thermal stress after laser welding can be reduced by heat treatment at different temperatures prior to laser irradiation. [Display omitted] • Al–Cu compound can be avoided during the laser welding process by the electroless nickel layer. • Residual thermal stress can be decreased by controlling the pre-heat treatment temperature for the metal before the laser weld. • Tension strength of welded joint will be decided by the laser scan speed in the welding process. • The contact area of the Al–Cu interface will affect the residual thermal stress after laser welding. [ABSTRACT FROM AUTHOR]

Al–10%Si–2%Cu alloys have been widely used in high-value industries (e.g., aerospace and automobiles) because of their lower specific gravity; however, galvanic corrosion rendered these alloys to have poor corrosion resistance. Therefore, the microstructure and corrosion properties of Al–10%Si–2%Cu alloys were investigated with respect to the lanthanum (La) content. All Al alloy samples were synthesized using gravity casting, with added La contents of 0.00, 0.25, 0.50, 0.75, and 1.00 wt%, and were characterized using microstructural characteristics analysis and electrochemical tests. Adding 0.5 wt% La (xLa-0.5) indicated the finest structure, which had a 4% lower α-Al area fraction than the La-free alloy (xLa-0). However, the area fraction of a 1 wt% La-added (xLa-1) alloy was 2.4% higher than that of xLa-0. The corrosion current density (Icorr) of the xLa-0.5 was 1.09 μA/cm2, representing a 68% decrease as compared to that of xLa-0, and xLa-0.5 reached the highest polarization resistance value (7.32 × 103 Ω·cm2). The improvement in corrosion resistance of xLa-0.5 was due to the rapid and dense formation of a passivation layer induced by its fine structure, as well as the precipitated phase by enhancing the dispersibility of Cu. [ABSTRACT FROM AUTHOR]

The phase diagram of the Fe-Zn binary system was evaluated based on the CALPHAD method with reference to the latest experimental data. The solubility ranges of the intermetallic compound phases, Γ-Fe4Zn9, Γ1-Fe11Zn40, δ1k-FeZn7, δ1p- Fe13Zn126, and ζ-FeZn13 were modeled considering their structures consisting of Zn12 icosahedra with Fe at the center (Fe1Zn12 clusters) as well as glue-like Fe and Zn atoms, and the miscibility gap between the δ1k and δ1p phases was also taken into account in the present calculations. The solubility of Fe in the liquid and (ηZn) phases that was confirmed as dozens of times larger than the values reported in the earlier literature could be calculated by introducing Fe1Zn12 associates to these solution phases. Consequently, all phase equilibria were adequately reproduced by the thermodynamic models and parameters revised in the present study. [ABSTRACT FROM AUTHOR]

Using our new program code, we have calculated the temperature dependence of the Seebeck coefficient ( S - T ) in the linearized Boltzmann transport equation with a constant relaxation time (LBT-CRT) for Fe2VAl (cF16) and its quaternary compounds for the range from − 263 °C (10 K) to 727 °C (1000 K). We revealed that Fe2VAl compound free from any defects exhibited the Seebeck coefficient with a negative sign at odds with experimental data with a positive sign. However, this dilemma could be removed after the introduction of Al/V near neighbor inversion defects into the perfect Fe2VAl. A key point in developing a reliable temperature-dependent Seebeck coefficient software lies in how precisely we calculate the density of states times square of the group velocity v x 2 along the direction x of thermal gradient. The present method is contrasted to the Fourier Transform Interpolation method in BoltzTraP developed by Madsen and Singh (2006). Nevertheless, both could reproduce the experimental data of Fe2VAl once the inversion effect was taken into account. Our new software allows us to seek the origin of characteristic behaviors in the S - T curve by decomposing the electronic parameter above into sub-bands and analyzing the sub-band dependence of the energy spectrum A ε in the LBT-CRT equation. [ABSTRACT FROM AUTHOR]

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The rapid development of space exploration technology was intensifying the desire for lead-free solders with high performance and reliability under extreme temperature environments. In this study, the influence of TiO2 nanoparticle addition on the microstructure, growth behavior of interfacial intermetallic compounds (IMCs) and shear property of Sn-3.0Ag-0.5Cu (SAC305)/Ni micro solder joints under thermal shock from 77 K to 423 K was systematically investigated. The results indicated that the grain size of β-Sn, IMC (Ag3Sn and (Cu,Ni)6Sn5) particles inside the solder was refined by adding 0.05 and 0.1 wt% TiO2 nanoparticles. Due to the spalling of interfacial IMCs into the solder occurring in all micro joints during thermal shock, the thickness of interfacial IMCs did not show a monotony increasing trend with increasing thermal cycles. However, the micro composite solder joint added with 0.05 and 0.1 wt% TiO2 nanoparticles always exhibited thinner interfacial IMC thickness and higher shear force compared with the plain micro joints during thermal shock. The inhibiting effect of TiO2 nanoparticles on the interfacial IMC growth could be explained by the adsorption theory and grain boundary pinning theory. The improvement in shear property of micro composite solder joints was primarily induced by the refinement of IMC particles in the solder and the reduced growth rate of interfacial IMCs by adding TiO2 nanoparticles.

Homogenous enantioselective catalysis is nowadays the cornerstone in the manufacturing of enantiopure substances, but its technological implementation suffers from well‐known impediments like the lack of endurable catalysts exhibiting long‐term stability. The catalytically active intermetallic compound Palladium‐Gallium (PdGa), conserving innate bulk chirality on its surfaces, represent a promising system to study asymmetric chemical reactions by heterogeneous catalysis, with prospective relevance for industrial processes. Here, this work investigates the adsorption of 10,10′‐dibromo‐9,9′‐bianthracene (DBBA) on the PdGa:A(1¯1¯1¯$\bar{1}\bar{1}\bar{1}$) Pd3‐terminated surface by means of scanning tunneling microscopy (STM) and spectroscopy (STS). A highly enantioselective adsorption of the molecule evolving into a near 100% enantiomeric excess below room temperature is observed. This exceptionally high enantiomeric excess is attributed to temperature activated conversion of the S to the R chiral conformer. Tip‐induced bond cleavage of the R conformer shows a very high regioselectivity of the DBBA debromination. The experimental results are interpreted by density functional theory atomistic simulations. This work extends the knowledge of chirality transfer onto the enantioselective adsorption of non‐planar molecules and manifests the ensemble effect of PdGa surfaces resulting in robust regioselective debromination. [ABSTRACT FROM AUTHOR]

This work provides an efficient method to synthesize Ge nanorods through the reaction between intermetallic compound CaGe and ZnCl 2. By controlling the reaction temperature, Ge nanorods with different morphologies and crystallinity can be obtained. Particularly, the nanorods exhibit remarkable cycling stability and capacity retention even at −20 °C. These findings open up avenues for utilizing Ge nanomaterials in high-performance LIBs. [Display omitted] Germanium (Ge) nanomaterials have emerged as promising anode materials for lithium-ion batteries (LIBs) due to their higher capacity compared to commercial graphite. However, their practical application has been limited by the high cost associated with harsh preparation conditions and the poor electrode cycling stability in charging and diacharging. In this study, we successfully synthesized crystalline Ge nanorods through the reaction of intermetallic compound CaGe and ZnCl 2. Ge nanorods with different morphologies and crystallinity can be obtained through precisely controlling the reaction temperature. When employed as electrodes for LIBs, the Ge nanorods demonstrate exceptional long-term cyclic stability. Even after 1000 cycles at a high rate of 2C (1C = 1600 mA g−1), it exhibits a remarkable reversible capacity of around 1000 mAh/g. Furthermore, such Ge electrode displays excellent cycling performance across a wide temperature range. And it could achieve reversible capacities of 1267, 832, and 690 mAh/g, with the rate of 1C, at temperatures of 20, 0, and −20 °C, respectively. Above all, our study offers a cost-effective approach for the synthesis of crystalline Ge nanorods, addressing the concerns associated with high production costs. And the application of Ge nanorods as anode materials in LIBs over a wide temperature range opens up new possibilities for the development of advanced energy storage systems. [ABSTRACT FROM AUTHOR]

Intermetallic FeMnPt nanoparticles with fine sizes (4–7 nm) and ordered phases (L10 and L12) were successfully synthesized by a facile one-step solid-state reaction method. NaCl powder with size less than 10 μm was employed as the solid-state isolate medium and the mass ratio of precursors to NaCl powders was set as 1:300; the solid reaction was done at 780 °C under a reducing atmosphere (90% Ar + 10% H2) for 180 min. The electrocatalytic hydrogen evolution reaction (HER) performances in both acidic and alkaline solutions were tested. Increasing the Mn precursor amounts in the solid-state reaction process would increase the content of Mn and Pt elements, transform the crystal structure from the L10-phase to the L12-phase, and increase the grain sizes of FeMnPt nanoparticles. Comparing the electrocatalytic HER performance of intermetallic FeMnPt nanoparticles in acidic and alkaline solutions, it was found that the L12-FeMnPt nanoparticles with higher Mn and Pt contents presented a low electrocatalytic overpotential and high specific activity in acidic solution. However, the Mn-containing L10-FeMnPt nanoparticles with higher ordering degrees showed low electrocatalytic overpotentials and high electrocatalytic activity in alkaline solution. The electrocatalytic HER stabilities of intermetallic FeMnPt nanoparticles with different components and ordered phases were comparable in acidic and alkaline solutions. This study provides the guidance for discovering highly efficient intermediate HER catalysts for servicing different acidic and alkaline environments. [ABSTRACT FROM AUTHOR]

The findings of this study provide valuable insights into the electrochemical characteristics of high-chromium white cast irons (HCCIs) and their suitability as impellers in flue-gas desulfurizer (FGD) slurry pumps of coal-fired power plants. By evaluating the corrosion and wear resistance of HCCI specimens with varying Cr contents, it was confirmed that the corrosion mechanism of HCCI involves micro-galvanic corrosion between the matrix and iron–chromium and carbon intermetallic compounds. Furthermore, the study revealed that HCCI with 32 wt% Cr content exhibited superior corrosion resistance, owing to the full-ferrite matrix with complete Cr dissolution that facilitated the enrichment of Cr(OH)3 and Cr2O3 on the HCCI surface. The results demonstrate that the addition of 32 wt% Cr to HCCI enhances its passivation ability and improves its ability to resist both micro-galvanic corrosion and erosion–cavitation. Finally, the performance of the impeller fabricated with HCCI containing 32 wt% Cr was validated in a real environment for 16 months with a FGD slurry pump, and it was found to be in excellent condition, further highlighting the effectiveness of HCCI for use as impellers in FGD slurry pumps. [ABSTRACT FROM AUTHOR]

This paper considers the application of two known models for the evaluation of distortion in high entropy shape memory alloys with the B2 structure. Distortion was calculated using the hard sphere and soft sphere models for binary TiNi and senary Ti-Hf-Zr-Ni-Cu-Co alloys with different chemical composition. It was shown that both models could not be used because they gave a high distortion value even for binary Ti49Ni51 alloy. Distortion was so large for all alloys that they must be amorphous. However, this contradicted the experimental data according to which all alloys were crystalline with the B2 structure. A modification of both models was proposed taking into account that the TiNi alloy is an intermetallic compound. The formation of intermetallic compound was accompanied by a change in the spatial distribution of electron density around the nuclei of interacting atoms, which led to a change in the atomic sizes. The proposed modification gave the distortion value that was consistent with the lattice stability criterion for alloys where the concentration of each alloying element did not exceed 5 at %. [ABSTRACT FROM AUTHOR]

The paper presents a method for the synthesis of metal pastes and diffusion-hardening alloys based on gallium by intensive vibrational mixing of powder components: solid gallium and a complex of filler powders. Using this method (with a specially selected fractional composition of powdered components), a series of samples of Cu–Ga–Sn alloys were obtained—one of the "classic" systems used (with various additives) as metal solder adhesives and dental filling materials. Structural, thermochemical (DSC), physical and mechanical properties, phase composition of initial and hardened samples are presented. When mixing, dosing and storing the components of the initial powder mixture, there is no noticeable segregation, contact-reactive melting of the components. The production of gallium pastes in this work includes the synthesis of the liquid metal component in situ, in the process of vibration treatment of the powder mixture. In addition to ease of use, this method, apparently, can provide new opportunities for the design of the structure of gallium pastes, putties, hard metal solder adhesives and filling materials. [ABSTRACT FROM AUTHOR]

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