Ag Alloy Research Articles

Influence of cooling rate on the corrosion behavior of Al–Zn–In–Mg–Ag sacrificial anode

The cooling curves of the Al–Zn–In–Mg–Ag alloys in copper mold, iron mold, and 400 °C-preheated iron mold cast were simulated and three solidification rates were calculated to be 7.05 °C/s, 0.76 °C/s, and 0.28 °C/s. The effects of cooling rate on the microstructure, electrochemical characteristics, and corrosion morphologies of Al–Zn–In–Mg–Ag alloys are investigated. The results demonstrate that the alloy with a low cooling rate has the lowest self-corrosion rate (0.09 mm/year), the highest actual capacity (2503.16 Ah/Kg2), as well as the highest anode current efficiency (87.46%). The anode current efficiency of the Al alloys is affected by the self-corrosion and the detachment of the second phases and grains. As the cooling rate decreases, the grain size becomes larger, the amount of the MgZn2 second phase decreases, and the content of In, Zn, and Ag activation elements increases in the matrix. The corrosion of the Al–Zn–In–Mg–Ag alloy initiates from the micro-galvanic corrosion between the MgZn2 second phase and the Al matrix. It then extends along the grain boundaries and towards the intragranular, accompanied by the shedding of the MgZn2 particles and the grains.

Developing a high-speed-extruded BMZQ5100 alloy with higher strength and microstructural thermal stability than AZ91 alloy

A new Mg-5Bi-1Mn-0.5Zn-0.2Ag (BMZQ5100, wt%) alloy is developed and analyzed comparatively its extrudability, microstructure, mechanical property and thermal stability with a commercial AZ91 alloy. The results show that the BMZQ5100 alloy can be successfully extruded at a high extrusion speed (ES) of 30 m/min without surface cracks, but there are a large number of hot cracks occurred on the low-speed-extruded AZ91 alloy surface (ES: 5 m/min). For the 30 m/min extruded BMZQ5100 alloy (BMZQ5100-E30), it exhibits a completely dynamic recrystallized (DRX) grain structure with a slightly larger grain size and stronger basal fiber texture than the 2 m/min extruded AZ91 alloy (AZ91-E2) without surface cracks. In terms of second phase, the former alloy contains submicron Mg3Bi2 phases at grain boundaries (GBs), nano-scale Mg3Bi2 and α-Mn particles within grain interiors, along with the co-segregation of Zn and Ag at GBs. The latter alloy has a continuous network of submicron Mg17Al12 phases along GBs, but no any solute segregation is observed at GBs. The BMZQ5100-E30 alloy exhibits more excellent mechanical properties with a tensile yield strength of ∼ 271 MPa, an ultimate tensile strength of ∼ 319 MPa and an acceptable elongation-to-failure of ∼ 8%, compared with the AZ91-E2 alloy. The GB strengthening, precipitation strengthening and solute segregation strengthening on the TYS occupy ∼ 46.2, ∼ 45.5 and ∼ 8.3%, respectively. In addition, the BMZQ5100-E30 alloy has higher microstructural thermal stability than the AZ91-E2 alloy, because of second phase pinning and solute segregation at GBs to effectively inhibit the grain growth during annealing.

Effect of Silver Content and T4 Treatment on the In Vitro Degradation Behavior of Gasar Porous Mg–Ag Alloy

Mg–Ag alloy has potential as a material for bone tissue repair, but the faster degradation rate in vivo limits its use in medical applications. In this study, pure Mg and Mg99.5Ag0.5 alloy with a porous structure are prepared using the metal/gas eutectic unidirectional solidification method (Gasar process). The influence of introducing Ag on the degradation behavior of porous Mg99.5Ag0.5 and pure Mg is investigated. The addition of Ag increases the compressive strength and elastic modulus of the material. The corrosion resistance of as‐cast Mg99.5Ag0.5 alloy decreases due to localized aggregation of Ag in the alloys. Therefore, the T4 (solution treatment) is chosen for the Mg99.5Ag0.5 alloy. After T4 treatment, due to the uniform distribution of Ag atoms in the alloy, the corrosion behavior on the alloy surface is more uniform, and a denser Mg(OH)2 passivation layer is formed on the surface, which reduces the degradation rate of Mg99.5Ag0.5. Importantly, insoluble Ca–P compounds in the form of hydroxyapatite (HA) phases gradually grown on passivated layers of porous T4 Mg99.5Ag0.5 contribute to bone growth. This indicates the feasibility of using the T4 Gasar porous Mg99.5Ag0.5 alloy as a potential tissue engineering scaffold.

A Lithiophilic–Lithiophobic Gradient Solid Electrolyte Interface Toward a Highly Stable Solid‐State Polymer Lithium Metal Batteries

AbstractThe functional lithiophilic−lithiophobic gradient solid electrolyte interphase (SEI) between Li‐metal anode and solid‐state polymer electrolytes may be effective in addressing the long‐standing issue of side reactions and Li‐dendrite growth during repeated deposition or dissolution in solid‐state polymer‐based high‐energy‐density batteries. Herein, a reliable lithiophilic–lithiophobic gradient SEI (G‐SEI) of LiAg‐LiF/Li3N is in situ formed by AgTFSI, used as an additive for polyethylene oxide‐based electrolyte (PEO‐Ag). The upper layer consists of a lithiophobic LiF/Li3N‐rich layer, wherein LiF possesses a high interfacial energy, while Li3N enables fast Li+ diffusion, which synergistically facilitates the uniform deposition of Li+. Lithiophilic Li–Ag alloy can effectively reduce the nucleation overpotential and promote more planar growth of lithium. Furthermore, such G‐SEI possesses a high mechanical modulus, mitigating the penetration of dendrites through the SEI and thereby preventing the continuous degradation of the PEO‐based electrolyte. As a result, an over three times improvement in the lifespan of Li | PEO‐Ag | LFP cell is achieved, demonstrating an 81.4% capacity retention rate after 500 cycles at 1C, as compared to Li | PEO | LFP cell with common SEI. Thus, the developments of the lithiophilic‐lithiophobic gradient SEI provide a substantial path toward high‐performance solid‐state lithium batteries.

Enhanced superplasticity of ultrafine-grained WEQ612 magnesium alloy via the coupling effect of grain boundary segregation and dense precipitation

Achieving low-temperature, high-strain-rate (LTHSR) superplasticity is important for preparing rare-earth (RE)–Mg alloy products with complex shapes. Herein, an ultrafine-grained Mg–6.22Y–0.98Er–2.11Ag (wt%, WEQ612) alloy was prepared via equal-channel angular pressing (ECAP). After 16 passes of ECAP and aging at 473 K for 58 h, an average grain size of 600 nm was achieved, and there was a high density of intergranular precipitates with an average size of approximately 180 nm. The WEQ612 alloy exhibited excellent superplasticity during superplastic deformation, with elongations of 451% at 523 K and 1 × 10−4 s−1, and 834% at 573 K and 1 × 10−2 s−1. The high density of intergranular precipitates, which were uniformly distributed at the grain boundaries, promoted dynamic recrystallization (DRX) during superplastic deformation and inhibited grain growth. The grain boundary co-segregation of Y and Ag further improved the grain boundary stability of the alloy. Despite the general consensus that grain boundary sliding (GBS) is the main mechanism of superplasticity, a more complex role of GBS and DRX was identified in this study. The identified mechanism provides a reference for GBS and grain boundary rotation as well as dislocation motion during superplastic deformation, and helps to describe the intermediate processes that occur during superplastic deformation. Thus, this study provides insights into the development of LTHSR superplastic RE–Mg alloys.

Microstructure evolution and mechanical properties of wire-arc-additively manufactured Al–Cu–Mg–Ag alloy

In this article, Al–Cu–Mg–Ag specimens were successfully wire-arc-additive-manufactured based on by gas metal arc process to investigate the evolution of microstructure and mechanical properties. The results showed that the grain morphology and pore size in the printed specimens varied in height direction. Under the influence of repeated thermal cycling, which affected the solid-state diffusion of the deviated elements at the grain boundaries, the distribution of the nanoscale second phase appeared significantly different in the height direction. The precipitation phase changes caused the microhardness of the printed specimens to decrease gradually from a peak of 125 HV and stabilise at around 100 HV. The changes in the printed specimens’ horizontal mechanical properties were insignificant mainly due to interlayer porosity.

Precipitation evolution of Al-Zn-Mg-Cu-(Ag) alloys with a low Zn/Mg ratio

The influence of minor Ag on the precipitation evolution of the Al-4.2Zn-2.8Mg-1.0Cu (wt.%) alloy from early stages to over-aged stages at 150 °C was investigated. Surprisingly, co-precipitation of strengthening phases T′ and η′ are found in both Ag-free and Ag-added alloys. With Ag addition, precipitation of both T′ and η′ is refined and increased, such that the age-hardening capabilities and peak-aged tensile strength are improved. In addition, the quantitative proportion of η′ precipitates increases with the increase of Ag content due to the increase in the (Zn+Cu)/Mg ratio of nucleating particles. The narrowed precipitate-free zones (PFZs) are considered responsible for the undiminished fracture elongation in Ag-added alloys. Essentially, these effects of Ag are closely related to the strong Ag-vacancy and Ag-solute interactions. In over-aged stages, the Ag-added alloys still possess higher hardness values compared to the Ag-free alloy, which is related to precipitate coarsening mechanisms. The Ag-free alloy follows classical coarsening behavior by solid solution mediated diffusion, while the Ag-added alloy follows two possible coarsening mechanisms, coalescence of aggregates and diffusion of atoms. The smaller average size and higher residual number density of precipitates benefited from the slow diffusion-controlled coarsening behavior depending on the precipitate composition characteristics of the two-stage differentiation and the precipitate distribution characteristics of high-density dispersion in early-aged stages could explain why the hardness of Ag-added alloy keeps at a higher level than that of Ag-free alloy even after 1000 h ageing. Meanwhile, the transformation of metastable phases to stable phases is inhibited due to the addition of Ag, such that GP zones, T′, η′, η and T phases coexist even after 14 d of ageing. In terms of phase composition, the addition of Ag decreases the ratio of Mg/(Al+Zn) in T-type phase. For the Ag-added alloy, the sum concentration of Zn+Mg in η′ phase is about 10 at.% higher compared to T′ phase, and η phase continues to have a high sum concentration of Zn+Mg, besides, the Zn/Mg ratio and Cu concentration exhibit obvious differences from T phase.

Effect of large deformation on microstructure and properties of copper alloy wire

Cu–Ag alloy wire with different deformations and Ag contents of 1%, 2%, and 4% are prepared using vacuum continuous casting technology combined with cold drawing and intermediate annealing processes. The evolution of microstructure, electrical properties, and mechanical properties of the Cu–Ag alloy wire is investigated, and a relationship model between wire diameter, Ag content, and alloy wire properties is established. The results showed that the directionally solidified billets exhibited good elongation and are suitable for drawing fine wire. As the Ag content increased, the twinning content inside the Cu–Ag alloy wire also increased significantly. It is found through Strain++ characterization that there is non-uniform deformation within the wire, and the tensile and compressive strains that exist interactively tend to aggregate within the twins. The properties of the Cu–Ag alloy wire with different diameters varied significantly at different stages of deformation, showing a pronounced size effect below 1 mm. With decreasing wire diameter or increasing Ag content, the DC resistance, resistivity, and tensile strength of the Cu–Ag alloy wire gradually increased, while the conductivity decreased. The effect of Ag content on elongation is not significant. Statistical analysis revealed that the established performance model had high predictive accuracy and could provide references for the optimization of production processes for Cu–Ag alloy wire.

Recyclable Fe3O4@SiO2@PEI-DTC@Au-Ag nanocomposites as a SERS platform for sensitive detection of thiram on fruit surfaces

Equipped with surface-enhanced Raman scattering (SERS) effect and magnetic manipulation capacity, a new paradigm of recyclable SERS substrates based on Fe3O4 nanoparticles (NPs) @SiO2@PEI-DTC adhesive layer @Au-Ag alloy quantum dots (QDs) were successfully prepared via engineering hydrothermal and seed deposition techniques. The SERS performance and uniformity of those substrates with different gold-silver (Au-Ag) weight ratios were evaluated by 4-aminothiophenol (4-ATP) molecules, revealing that the relative standard deviations (RSDs) of all substrates were less than 12 %, with the optimal SERS substrate achieving an enhancement factor (EF) of up to 1.39 × 105. This phenomenon can be attributed to the magnetic core and plasmonic resonance properties of Au-Ag alloy QDs, which result in abundant interparticle hotspots in the Fe3O4@SiO2@PEI-DTC@Au-Ag (FSPAA) nanocomposites. Furthermore, the optimal FSPAA nanocomposite was employed as a SERS substrate for rapid non-destructive detection of thiram on fruit surfaces. The SERS signal intensity exhibited a robust manifesting a linear association with thiram concentration within the span of 1 × 10−4 to 1 × 10−9 M, and the minimal detectable concentration was 1.04 × 10−10 M. The FSPAA core–shell nanocomposites exhibit high reusability and reliability and hold great promise for the practical applications in on-site assessment of food/environmental safety, as well as in spectroscopic identification of molecules adsorbed onto fruit surfaces.

Enhancing strength-ductility synergy in an extruded Al-Cu-Li-Mg-Ag alloy via homogeneous GP zones and dislocation configuration

Balancing strength and ductility proves challenging in high-strength wrought Al-Cu-Li alloys, particularly in extruded rods. The abundance of subgrain structures hinders dislocation movement, inevitably sacrificing the ductility. Herein, an effective strategy for enhancing the strength-ductility synergy in an extruded Al-3.7Cu-1Li-0.40Mg-0.75Ag alloy was reported by developing a novel combinatorial pretreatment (CPT), including pre-ageing after solution treatment, followed by pre-stretching. Subsequently, the CPT alloys undergo artificial ageing at 150 °C. Desirable comprehensive mechanical properties (YS = 668 MPa, UTS = 700 MPa, and EL = 12.5 %) were obtained through pre-ageing at 110 °C before 4 % pre-stretching. Notably, the elongation showed a remarkable improvement of 60.3 % compared to the non-CPT sample, without sacrificing the yield strength. Microstructure analysis indicates that the interactions between the GP zones and dislocations facilitated energy dissipation during pre-stretching, effectively mitigating local stress concentration. Consequently, promoted ductility was realized through a more uniform dislocation distribution. Furthermore, the dense GP zones formed during pre-ageing served as the heterogeneous nucleation sites for precipitates, increasing the volume fraction of θ′ phases. This adjustment in dislocation motion further contributed to ductility improvements. Our approach offers new insights into developing high-performance extruded Al-Cu-Li alloys with both high strength and desirable ductility.

Preparation and mechanisms of Cu–Ag alloy fibers with high strength and high conductivity

Cu–Ag alloy fibers are known for their excellent electrical and thermal conductivity, and are widely used in various fields, such as electronics, transportation, and processing due to their low price and simple preparation process. Nevertheless, this trade-off relation between strength and electrical conductivity of Cu–Ag alloys restricts their scope of application. In order to prepare Cu–Ag alloy fibers with high strength and high electrical conductivity, three different processes: cold drawing, surface electrodeposition and electrolytic polishing, are investigated and comprehensively utilized. By comparing the evolution of microstructure and properties in Cu–Ag alloy fibers, along with the corresponding mechanisms for strengthening and conductivity, one most suitable process path is explored. Cold-drawing is utilized to reduce the grain size, which, in turn, enhances the strength of the fibers. Meanwhile, it refines the internal grains of the alloy by shearing and deflecting each other, ultimately resulting in a fiber texture along the drawing direction. The main contributors to the strength of Cu–Ag alloy fibers are dislocation strengthening, grain boundary strengthening, and texture strengthening. The slight difference is that for electrical conductivity, dislocation and grain boundary play a crucial role. Electrodeposition of copper on the fiber surface is an effective method for improving the electrical conductivity of the fiber, which is achieved by creating a dense conductive pathway on the surface of the fiber. However, this process leads to a reduction in strength. Therefore, electrolytic polishing is subsequently used to regulate the plating thickness in order to obtain Cu–Ag alloy fiber with synchronous increase of strength and electrical conductivity.

Effect of Cr addition on the microstructure evolution, precipitation behavior and properties of Cu–Ag alloy

This investigation systematically explores the impact of minor Cr additions on the microstructural evolution, precipitation kinetics, mechanical properties, and electrical properties of Cu–Ag alloys, with a specific focus on Cu–6 %Ag-(0.4 %Cr). The alloys underwent casting through a vacuum induction furnace, followed by meticulous treatments involving solution heat and aging at varied temperatures and durations. Results indicate a significant improvement in the mechanical properties of Cu–Ag alloy upon Cr addition, with only a slight reduction in electrical conductivity. As per differential scanning calorimetry (DSC) measurements, the activation energy for continuous precipitation in the Cu–Ag–Cr ternary alloy is slightly higher than that in Cu–Ag. However, Cu–Ag–Cr lacks peaks corresponding to the discontinuous phase. Microstructural analysis unveils that Cr incorporation suppresses the discontinuous precipitation of Ag, fostering continuous precipitation during aging. Moreover, both micro-sized and nano-sized Cr particles were detected in the Cu–Ag–Cr alloy, contributing to the formation of finely spaced continuous Ag precipitates and fine Cr precipitates. This intricate microstructure imparts higher hardness and strength to the alloy compared to Cu–Ag. Specifically, following aging treatment at 450 °C for 2 h, the Cu–6 %Ag-0.4 %Cr alloy exhibited a remarkable increase of 76.1 % in hardness, 43.6 % in strength, and a moderate decrease of 15.8 % in conductivity.

Using Solution Heat Treatment and Multi Directional Forging to Improve the Mechanical and Corrosion Properties of an Mg–2Zn–0.2Ag Alloy

Using Solution Heat Treatment and Multi Directional Forging to Improve the Mechanical and Corrosion Properties of an Mg–2Zn–0.2Ag Alloy

3D hotspot engineering and analytes strategy enabled ultrasensitive SERS platform for biosensing of depression biomarker

Nowadays, the diagnose of depression mainly relies on clinical examination while impossible to accurately evaluate the occurrence of depression. Chemical approaches are captivating to analyze stress biomarkers for feedbacking body's endocrine response to stress stimuli. However, it remains challenging in exploring accurate, reliable and sensitive approaches. Herein, we rationally design a newly SERS platform with integrated hotspots engineering and analyte strategy to achieve highly sensitive analysis for estrogen, a typical depression biomarker in adolescent female. On the one hand, the 3D micro/nano plasmonic substrate containing Au–Ag Alloy Nanourchins (AAA-NUs) and arrays-based monolayer films of Au nanoparticles (Au NSs) was constructed to achieve high density and availability of hotspots. On the other hand, the analyte strategy was designed via rapid azotizing reaction to further enhance the scattering cross-section of estrogen in the form of azido compounds. With the synergism of them, the proposed SERS platform displayed high sensitivity for estrogen with a limit of detection down to 10−11 mg/mL. More importantly, the blood estrogen levels of depressed patients were evaluated via the proposed SERS platform and presented high consistence with clinical diagnostic results. This integrated SERS platform paves the way for universal and ultrasensitive biosensing and possess great potential for applying in multi-target detection and disease prediction.

Effect of Ag agglomeration-driven nanovoids formation on fatigue reliability of Cu–Ag alloy flexible interconnects

Fatigue failure under cyclic deformation remains longstanding challenge in the flexible interconnect for the long term application. In this study, we design Cu–Ag alloy interconnects with excellent fatigue resistance by adopting nanovoid structures acquired by a simple post-annealing process. Nanovoids are generated during Ag agglomeration in the Cu matrix because of the low solubility of Ag in Cu, which enhances the fatigue property of a Cu–Ag alloy deposited on a polyimide film. The effect of high-density nanovoids located at the triple junction of the Cu and Ag grain boundaries on the mechanical fatigue lifetime is investigated by microstructure analysis (HAADF, HR-TEM and ASTAR™-coupled TEM). The fatigue damage of the Cu–Ag alloy has been observed to originate from grain boundary decohesion, unlike typical long fatigue cracks and extrusions. This can be attributed to the uniform distribution of nanovoids, which leads to stress concentration relief and consequently reduces the level of deformation.

Evolution of Microstructure and Mechanical Properties of Novel Al-Mg-Mn-Ag-Cr-Zr Alloy

In order to reinforce the mechanism of Ag in 5xxx aluminum alloys with low magnesium, research on the microstructure and mechanical properties of an Al-Mg-Mn-Ag-Cr-Zr alloy was conducted using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), hardness measurement, and tensile testing. The as-cast microscopic structure of the alloy comprises the Al6(Mn, Fe) phase and the T-Mg32(Al, Ag)49 phase. Changes in the characteristics of the investigated alloy were clear during the aging process. Based on the findings obtained from TEM and SAED analysis, it was evident that the predominant strengthening phase during the peak-aged stage is the β″ phase, observed when the alloy is aged for 24 h at 160 °C. The β″ phase had a L12-type crystal lattice architecture and presented a completely coherent relevance with the Al-matrix. The lattice parameter, a, of the β″ phase was 0.408 nm. The mechanical properties of the peak-aged alloy increased greatly as compared to the as-quenched alloy. The tensile strength exhibited a rise from 410 MPa to 449 MPa, representing a 9.5% increase, while the yield strength demonstrated an increase from 185 MPa to 273 MPa, indicating a significant enhancement of 47.5%. The method used in the present study has solved the problem of 5xxx aluminum alloys not being heat treatable for strengthening to a significant degree, considerably improving the alloy strength. In addition, new methods and foundations for exploiting new-type Al-Mg based alloys and developing high-strength aluminum alloys are provided in this study.

Maximizing the yield stress via synergistic optimization of grain sizes and solute concentrations in extremely fine nanograined metals: A molecular dynamics study

Molecular dynamics simulations are employed to investigate the grain boundary (GB)-segregation-induced strengthening and determine the maximal yield stress (MYS) in extremely fine nanograined Cu–Ag alloys, with variable grain sizes ranging from 5.2 to 17.9 nm alongside diverse solute concentrations. We discover that deformation mechanisms and yield stresses are adjustable through tailoring GB stability. The yield stress increases upon increasing solute concentration, up to a maximum (namely MYS) at a critical solute concentration for each grain size. The MYS shows a maximum of 3.70 to 3.72 GPa at a critical grain size of 7.3 to 10.3 nm. The strengthening and softening mechanisms related to GB segregation are uncovered, based on the model calculations and the dislocation analyses. Beyond the critical grain size, GB segregation suppresses GB-mediated processes while allowing dislocation activities, thereby causing a continuous strengthening. In contrast, below the critical grain size, the GBs, although being saturated, cannot withstand the resistance for GB deformation, which leads to a softening. This work presents a strategy to maximize the yield stress via synergistic optimization of grain sizes and solute concentrations, and provides insights into the design of ultrahigh-strength materials.

Electrochemical behavior and discharge performance of dilute Mg-Bi-based alloy as an anode for primary Mg-air battery

In this study, the electrochemical behavior and discharge performance of dilute Mg-0.5Bi-0.5Ca-0.5Ag alloy as an anode for primary Mg-air battery are studied and compared with those of Mg-0.5Bi base alloy. The results show that the addition of trace Ca and Ag to Mg-0.5Bi base alloy is conducive to enhancing the dynamic recrystallization (DRX) extent, reducing the basal texture component and kernel average misorientation value. In addition, re-deposited Ag in the discharge products can improve discharge activity by promoting the dissolution of the Mg matrix and rupturing the discharge product film. For these reasons, the Mg-0.5Bi-0.5Ca-0.5Ag anode presents a high level of synergy between cell voltage and anodic efficiency by means of the enhanced anode dissolution kinetics and effective reactive area. Therefore, dilute MgBi based anode micro-alloyed with Ag and Ca presents a great potential to be developed as novel anode material for Mg-air battery.

Characteristics of dental materials in the oral cavities of Asian individuals between their 20s and early 40s living temporarily in Japan based on 38 case studies.

Characterization of materials used in dental restorations and fixed prostheses is useful for personal identification. This study investigated the dental treatment trends and use of metal materials among non-Japanese Asian temporary residents and Japanese individuals aged from 20 to 40 years living in a city in Japan. Analysis of 38 participants from different Asian countries showed prominent use of resin fillings, with metal element analysis revealing nickel-chromium (Ni-Cr) or cobalt-chromium (Co-Cr) alloys. Among five Japanese participants of the same age with dental metal treatment scars, resin fillings and silver-palladium-copper-gold (Ag-Pd-Cu-Au) or silver-indium (Ag-In) alloys were observed. This study suggested some regional differences in dental material choices in Asia.

Synthesis of RhH-doped Au-Ag alloy nanoclusters and dopant evolution.

Doping atomically precise metal nanoclusters (NCs) with heterometals is a powerful method for tuning the physicochemical properties of the original NCs at the atomic level. While the heterometals incorporated into metal NCs are limited to group 10-12 metals with closed d-shells, the doping of open d-shell metals remains largely unexplored. Herein, we report the synthesis of Rh-doped Au-Ag alloy NCs by a metal-exchange reaction of [RhHAg24(SPhMe2)18]2- NCs with an Au-thiolate complex. Combined experimental and theoretical structural studies revealed that the synthesized product is a dianionic [RhHAuxAg24-x(SPhMe2)18]2- NC (x = 8-12), consisting of RhH dopant, Au-rich kernel, and Ag-thiolate staple motifs, with the superatomic 8-electron configuration (1S21P6). Under aerobic conditions, the synthesized NCs underwent kernel evolution to generate a 6-electron [RhAuxAg24-x(SPhMe2)18]1- NC (1S21P4), which was initiated by the desorption of hydride from the kernel. Structural analysis of the [RhHAuxAg24-x(SPhMe2)18]2- NC suggests that the kernel evolution is induced by the change in chemical bonds surrounding the hydride in the Au-rich kernel.