Pub Date : 2025-12-05DOI: 10.1016/j.intermet.2025.109119
Faye Greaves , Vivian Nassif , Maria Alfredsson , Alan V. Chadwick , Ryan Parmenter , Jakub Čížek , Oksana Melikhova , Lei Lei , David M. Grant , Martin Dornheim , Sanliang Ling , Patrick Cullen , Claudia Zlotea
Refractory BCC high entropy alloy TiVZrNbHf is a promising material for solid-state hydrogen storage with high hydrogen sorption capacity but unfavourable thermodynamics of hydride phase, i.e. too stable hydride that need high temperature to reversibly recover the absorbed hydrogen. As an attempt to destabilize the hydride phase, this study reports on the effect of Al addition (limited concentrations: 5 and 10 at.%) into this alloy on the physicochemical and hydrogen sorption properties. Despite traces of a V-Al secondary phase, the BCC (TiVZrNbHf)1-xAlx alloys are random solid solutions which form high-capacity FCC hydride phases under hydrogen atmosphere at room temperature, as proven by synchrotron and neutron diffraction. Although Al decreases the hydrogen sorption capacity, the presence of a p element destabilizes the FCC hydride phase. A comparison with previous literature data helps understanding the role of Al which strongly depends on the chemical composition of the initial alloys. XANES studies allowed access to details of the electronic structure of the unoccupied levels complemented by density functional theory calculations. Moreover, the addition of Al favours the formation of larger open volume defects during hydride formation than the initial Al-free alloy which might explain the faster absorption kinetics in Al-containing alloys.
{"title":"The role of Al addition on the hydrogen sorption properties of TiVZrNbHf high entropy alloy","authors":"Faye Greaves , Vivian Nassif , Maria Alfredsson , Alan V. Chadwick , Ryan Parmenter , Jakub Čížek , Oksana Melikhova , Lei Lei , David M. Grant , Martin Dornheim , Sanliang Ling , Patrick Cullen , Claudia Zlotea","doi":"10.1016/j.intermet.2025.109119","DOIUrl":"10.1016/j.intermet.2025.109119","url":null,"abstract":"<div><div>Refractory BCC high entropy alloy TiVZrNbHf is a promising material for solid-state hydrogen storage with high hydrogen sorption capacity but unfavourable thermodynamics of hydride phase, <em>i.e.</em> too stable hydride that need high temperature to reversibly recover the absorbed hydrogen. As an attempt to destabilize the hydride phase, this study reports on the effect of Al addition (limited concentrations: 5 and 10 at.%) into this alloy on the physicochemical and hydrogen sorption properties. Despite traces of a V-Al secondary phase, the BCC (TiVZrNbHf)<sub>1-<em>x</em></sub>Al<sub><em>x</em></sub> alloys are random solid solutions which form high-capacity FCC hydride phases under hydrogen atmosphere at room temperature, as proven by synchrotron and neutron diffraction. Although Al decreases the hydrogen sorption capacity, the presence of a <em>p</em> element destabilizes the FCC hydride phase. A comparison with previous literature data helps understanding the role of Al which strongly depends on the chemical composition of the initial alloys. XANES studies allowed access to details of the electronic structure of the unoccupied levels complemented by density functional theory calculations. Moreover, the addition of Al favours the formation of larger open volume defects during hydride formation than the initial Al-free alloy which might explain the faster absorption kinetics in Al-containing alloys.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109119"},"PeriodicalIF":4.8,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.intermet.2025.109113
Lei Gao , Qi Li , Jiawei Xu , Xiang Jin , Juan Cheng
This study employs a low mixing enthalpy–high mixing entropy synergistic design strategy to synthesize Gd18.34+xDy18.33Er18.33-xAl20Fe25 (x = 0, 3, 6, 9) high-entropy metallic glasses (HE-MGs), systematically investigating their glass-forming ability (GFA) and magnetocaloric properties. The results demonstrate that all alloys exhibit distinct ferromagnetic-paramagnetic second-order phase transition (SOPT) near Curie temperatures (TC) of 75 K, 84 K, 95 K, and 103 K, respectively, validating the predictive significance of the de Gennes factor for TC tuning in rare-earth-based amorphous systems. Thermodynamic behavior is predominantly governed by f-d hybridization effects induced by 4f electrons, wherein reduced 4f electron concentration weakens hybridization, consequently diminishing thermal stability. Under a 7 T applied field, the maximum isothermal magnetic entropy change (|-ΔSMmax|) reach 6.59 J kg−1 K−1, 6.57 J kg−1 K−1, 5.06 J kg−1 K−1, and 4.99 J kg−1 K−1; full width at half maximum (ΔTFWHM) values measure 125.21 K, 138.12 K, 147.87 K, and 150.77 K; and relative cooling power (RCP) attain 825.11 J kg−1, 907.78 J kg−1, 748.30 J kg−1, and 752.54 J kg−1, respectively, highlighting exceptional potential for broad-temperature-range magnetic refrigeration. Scaling theory reveals deviations of critical exponents from mean-field predictions due to microstructural fluctuations and chemical short-range order inherent to the amorphous state. By modulating the Gd/Er ratio, this work simultaneously enhances glass-forming ability (GFA) and magnetocaloric performance, elucidating coupling mechanisms among rare-earth elements, spin-glass effect, and magnetic phase transition. These findings provide experimental and theoretical foundations for developing novel high-efficiency cryogenic magnetic refrigerants.
{"title":"Glass-forming ability and magnetocaloric performance of Gd18.34+xDy18.33Er18.33-xAl20Fe25 (x = 0, 3, 6, 9) high-entropy amorphous alloys","authors":"Lei Gao , Qi Li , Jiawei Xu , Xiang Jin , Juan Cheng","doi":"10.1016/j.intermet.2025.109113","DOIUrl":"10.1016/j.intermet.2025.109113","url":null,"abstract":"<div><div>This study employs a low mixing enthalpy–high mixing entropy synergistic design strategy to synthesize Gd<sub>18.34+<em>x</em></sub>Dy<sub>18.33</sub>Er<sub>18.33-<em>x</em></sub>Al<sub>20</sub>Fe<sub>25</sub> (<em>x</em> = 0, 3, 6, 9) high-entropy metallic glasses (HE-MGs), systematically investigating their glass-forming ability (GFA) and magnetocaloric properties. The results demonstrate that all alloys exhibit distinct ferromagnetic-paramagnetic second-order phase transition (SOPT) near Curie temperatures (<em>T</em><sub>C</sub>) of 75 K, 84 K, 95 K, and 103 K, respectively, validating the predictive significance of the de Gennes factor for <em>T</em><sub>C</sub> tuning in rare-earth-based amorphous systems. Thermodynamic behavior is predominantly governed by <em>f-d</em> hybridization effects induced by 4<em>f</em> electrons, wherein reduced 4<em>f</em> electron concentration weakens hybridization, consequently diminishing thermal stability. Under a 7 T applied field, the maximum isothermal magnetic entropy change (|-Δ<em>S</em><sub>M</sub><sup>max</sup>|) reach 6.59 J kg<sup>−1</sup> K<sup>−1</sup>, 6.57 J kg<sup>−1</sup> K<sup>−1</sup>, 5.06 J kg<sup>−1</sup> K<sup>−1</sup>, and 4.99 J kg<sup>−1</sup> K<sup>−1</sup>; full width at half maximum (Δ<em>T</em><sub>FWHM</sub>) values measure 125.21 K, 138.12 K, 147.87 K, and 150.77 K; and relative cooling power (<em>RCP</em>) attain 825.11 J kg<sup>−1</sup>, 907.78 J kg<sup>−1</sup>, 748.30 J kg<sup>−1</sup>, and 752.54 J kg<sup>−1</sup>, respectively, highlighting exceptional potential for broad-temperature-range magnetic refrigeration. Scaling theory reveals deviations of critical exponents from mean-field predictions due to microstructural fluctuations and chemical short-range order inherent to the amorphous state. By modulating the Gd/Er ratio, this work simultaneously enhances glass-forming ability (GFA) and magnetocaloric performance, elucidating coupling mechanisms among rare-earth elements, spin-glass effect, and magnetic phase transition. These findings provide experimental and theoretical foundations for developing novel high-efficiency cryogenic magnetic refrigerants.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109113"},"PeriodicalIF":4.8,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-02DOI: 10.1016/j.intermet.2025.109081
Nicholas Brooks , Lloyd Hackel , Keivan Davami
In this work the age-hardenability of alloy 625 (Inconel® 625) has been exploited by employing two surface engineering techniques known as laser peening and shot peening prior to aging to locally accelerate the nucleation and precipitation of γ՛՛ and δ intermetallic phases resulting in gradient precipitation hardening. Both laser peening and shot peening were observed to generate planar slip bands and dislocation tangles through work hardening resulting in different levels of strain hardening. A change in strengthening mechanisms was observed before and after aging where strain hardening yielded local gradient hardening prior to aging whereas a combination of precipitation and dislocation hardening was observed to further enhance gradient hardness following aging. The laser peened specimen was found to yield smaller and more densely packed γ՛՛precipitates in regions where lattice strain and increased microhardness were observed resulting from the planar slip bands and dislocation tangles generated prior to aging. Following aging of the shot peened specimen, coarse δ needle-like phases were observed at the near-surface with little observable γ՛՛ precipitates suggesting that the higher level of cold work imparted by shot peening, which resulted in a higher density of more narrowly spaced slip bands and dislocation tangles, accelerated the transformation from γ՛՛ → δ within the most intense strain hardened region. This is the first study in which the age-hardenability of alloy 625 has been exploited using these surface engineering techniques and provides insight into how these techniques can be employed as intermediate processing steps prior to aging to locally enhance precipitation kinetics.
{"title":"Gradient precipitation hardening in surface engineered alloy 625 following aging: Direct evidence of enhanced precipitation following local surface work hardening","authors":"Nicholas Brooks , Lloyd Hackel , Keivan Davami","doi":"10.1016/j.intermet.2025.109081","DOIUrl":"10.1016/j.intermet.2025.109081","url":null,"abstract":"<div><div>In this work the age-hardenability of alloy 625 (Inconel® 625) has been exploited by employing two surface engineering techniques known as laser peening and shot peening prior to aging to locally accelerate the nucleation and precipitation of γ՛՛ and δ intermetallic phases resulting in gradient precipitation hardening. Both laser peening and shot peening were observed to generate planar slip bands and dislocation tangles through work hardening resulting in different levels of strain hardening. A change in strengthening mechanisms was observed before and after aging where strain hardening yielded local gradient hardening prior to aging whereas a combination of precipitation and dislocation hardening was observed to further enhance gradient hardness following aging. The laser peened specimen was found to yield smaller and more densely packed γ՛՛precipitates in regions where lattice strain and increased microhardness were observed resulting from the planar slip bands and dislocation tangles generated prior to aging. Following aging of the shot peened specimen, coarse δ needle-like phases were observed at the near-surface with little observable γ՛՛ precipitates suggesting that the higher level of cold work imparted by shot peening, which resulted in a higher density of more narrowly spaced slip bands and dislocation tangles, accelerated the transformation from γ՛՛ → δ within the most intense strain hardened region. This is the first study in which the age-hardenability of alloy 625 has been exploited using these surface engineering techniques and provides insight into how these techniques can be employed as intermediate processing steps prior to aging to locally enhance precipitation kinetics.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109081"},"PeriodicalIF":4.8,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-02DOI: 10.1016/j.intermet.2025.109095
Ying Zheng , Guofu Lian , Meiyan Feng , Changrong Chen , Wei Zhang , Rongxin Chen , Yiheng Chi
TiAl alloys are widely applied in aerospace and energy industries owing to their high specific strength and lightweight advantages; however, their poor wear and corrosion resistance restricts broader use in harsh environments. In this study, SiC-reinforced composite coatings were fabricated on Ti-45Al-8Nb alloys using preheating-assisted laser cladding, with varying Y additions (0, 0.5, 1, 1.5, and 2 at.%) to investigate the effects of Y content on microstructural evolution, mechanical properties, and corrosion behavior. Microstructural analysis revealed that moderate Y addition (≤1 at.%) promoted the precipitation of strengthening phases such as Ti2AlNb and Ti3SiC2, forming a stable reticulated structure. This refinement improved microstructural homogeneity and density, leading to enhanced hardness and wear resistance. The 1 at.% Y coating exhibited the highest fraction of strengthening phases, with well-aligned columnar and ridge-like structures, yielding the maximum hardness (664.908 HV0.2), the lowest friction coefficient (0.397), and the minimum wear rate (1.994 mm3/N·m). In addition, the reticulated structure facilitated the formation of a dense and stable passive film, thereby improving corrosion resistance: the corrosion potential of the 1 at.% Y coating increased to −0.460 V, the corrosion current density decreased to 1.234 × 10−7 A/cm2, and the charge transfer resistance rose to 5074 Ω cm2. By contrast, with higher Y additions (≥1.5 at.%), precipitation of strengthening phases was inhibited and microstructural uniformity deteriorated. In the 2 at.% Y coating, strip- and column-like agglomerates formed with reduced hard-phase content, resulting in decreased hardness, elevated friction coefficient, and diminished wear and corrosion resistance. This work provides new insights into rare-earth modification strategies for optimizing laser-cladded TiAl alloys and establishes a theoretical basis for designing high-performance TiAl alloys with superior wear and corrosion resistance.
{"title":"Influence of Y content on the microstructure, wear, and corrosion resistance of laser-clad SiC-reinforced high Nb-TiAl alloys","authors":"Ying Zheng , Guofu Lian , Meiyan Feng , Changrong Chen , Wei Zhang , Rongxin Chen , Yiheng Chi","doi":"10.1016/j.intermet.2025.109095","DOIUrl":"10.1016/j.intermet.2025.109095","url":null,"abstract":"<div><div>TiAl alloys are widely applied in aerospace and energy industries owing to their high specific strength and lightweight advantages; however, their poor wear and corrosion resistance restricts broader use in harsh environments. In this study, SiC-reinforced composite coatings were fabricated on Ti-45Al-8Nb alloys using preheating-assisted laser cladding, with varying Y additions (0, 0.5, 1, 1.5, and 2 at.%) to investigate the effects of Y content on microstructural evolution, mechanical properties, and corrosion behavior. Microstructural analysis revealed that moderate Y addition (≤1 at.%) promoted the precipitation of strengthening phases such as Ti<sub>2</sub>AlNb and Ti<sub>3</sub>SiC<sub>2</sub>, forming a stable reticulated structure. This refinement improved microstructural homogeneity and density, leading to enhanced hardness and wear resistance. The 1 at.% Y coating exhibited the highest fraction of strengthening phases, with well-aligned columnar and ridge-like structures, yielding the maximum hardness (664.908 HV<sub>0.2</sub>), the lowest friction coefficient (0.397), and the minimum wear rate (1.994 mm<sup>3</sup>/N·m). In addition, the reticulated structure facilitated the formation of a dense and stable passive film, thereby improving corrosion resistance: the corrosion potential of the 1 at.% Y coating increased to −0.460 V, the corrosion current density decreased to 1.234 × 10<sup>−7</sup> A/cm<sup>2</sup>, and the charge transfer resistance rose to 5074 Ω cm<sup>2</sup>. By contrast, with higher Y additions (≥1.5 at.%), precipitation of strengthening phases was inhibited and microstructural uniformity deteriorated. In the 2 at.% Y coating, strip- and column-like agglomerates formed with reduced hard-phase content, resulting in decreased hardness, elevated friction coefficient, and diminished wear and corrosion resistance. This work provides new insights into rare-earth modification strategies for optimizing laser-cladded TiAl alloys and establishes a theoretical basis for designing high-performance TiAl alloys with superior wear and corrosion resistance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109095"},"PeriodicalIF":4.8,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.intermet.2025.109094
Mohammad Sajad Mehranpour , Mohammad Javad Sohrabi , Alireza Kalhor , Ali Heydarinia , Saeed Sadeghpour , Hamed Mirzadeh , Kinga Rodak , Krzysztof Radwański , Reza Mahmudi , Hyoung Seop Kim
The dilemma of achieving a strength-ductility synergy is a highly sought-after topic in the high-entropy alloys (HEAs) realm. Even HEAs capable of breaking the strength-ductility trade-off typically suffer from relatively low yield stresses. This challenge was addressed in the present work by introducing the Co47Cr20Fe12.5Ni12.5Mo5Ti3 HEA, which exhibits high solid-solution strengthening and high friction stress due to its high Mo and Ti contents leading to a yield stress of 527 MPa. In addition, excellent work-hardening behavior is achieved through the activation of twinning-induced plasticity (TWIP), enabled by an adjusted stacking-fault energy (SFE). The synergistic action of the TWIP effect and strong dislocation-based hardening (strain hardening) leads to an ultimate tensile strength of 1156 MPa and exceptional total elongation of 74 %. Overall, the proposed Co-rich HEA exhibits a desirable combination of strength and ductility compared to the most competitive HEAs reported in the literature.
{"title":"Extraordinary strength-ductility synergy in a novel high-entropy alloy via coupling multiple strengthening mechanisms","authors":"Mohammad Sajad Mehranpour , Mohammad Javad Sohrabi , Alireza Kalhor , Ali Heydarinia , Saeed Sadeghpour , Hamed Mirzadeh , Kinga Rodak , Krzysztof Radwański , Reza Mahmudi , Hyoung Seop Kim","doi":"10.1016/j.intermet.2025.109094","DOIUrl":"10.1016/j.intermet.2025.109094","url":null,"abstract":"<div><div>The dilemma of achieving a strength-ductility synergy is a highly sought-after topic in the high-entropy alloys (HEAs) realm. Even HEAs capable of breaking the strength-ductility trade-off typically suffer from relatively low yield stresses. This challenge was addressed in the present work by introducing the Co<sub>47</sub>Cr<sub>20</sub>Fe<sub>12.5</sub>Ni<sub>12.5</sub>Mo<sub>5</sub>Ti<sub>3</sub> HEA, which exhibits high solid-solution strengthening and high friction stress due to its high Mo and Ti contents leading to a yield stress of 527 MPa. In addition, excellent work-hardening behavior is achieved through the activation of twinning-induced plasticity (TWIP), enabled by an adjusted stacking-fault energy (SFE). The synergistic action of the TWIP effect and strong dislocation-based hardening (strain hardening) leads to an ultimate tensile strength of 1156 MPa and exceptional total elongation of 74 %. Overall, the proposed Co-rich HEA exhibits a desirable combination of strength and ductility compared to the most competitive HEAs reported in the literature.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109094"},"PeriodicalIF":4.8,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-28DOI: 10.1016/j.intermet.2025.109098
Seungchan Ka , Deborah Bae , Ashutosh Sharma , Jae Pil Jung , Hyun-Sik Kim
In this work, laser solder ball jetting (LSBJ) was used to bond electroless nickel immersion gold (ENIG) coated Cu pads on FR4 substrates. Lead-free SAC305 (Sn–3Ag–0.5Cu) solder balls (Ф 100 μm) were used for the LSBJ process. After LSBJ, the solder joints were reflowed for various reflow cycles (0, 1, 3, 5, and 7), each cycle consisting of 60 s. The microstructure and mechanical properties of the LSBJ solder joints so formed were studied after multiple reflow cycles. It was found that SAC/ENIG-Cu solder joints had higher shearing strength during multiple reflows. The shearing force of the solder joints remained almost stable with the increase in the number of reflow cycles. The fracture of SAC/ENIG-Cu solder joints in LSBJ (before reflow) mainly occurred in the bulk solder. In contrast, after reflow, it showed various combinations of bulk solder fracture, ball lift, and Cu-pad lift interface failure. The microstructure evolution of the solder joints during multiple reflows showed a continuous change in the chemical composition of the IMC layer. Large Ag–Sn and Cu6Sn5 phases near the IMC layer were found within the SAC solder joints on the Cu pads. The LSBJ process enables precise solder deposition and uniform bonding quality during initial joining; however, multiple reflow cycles can lead to progressive IMC growth, affecting long-term reliability. These results demonstrate that while LSBJ offers distinct advantages in controlled soldering, its performance stability under multiple reflows requires further optimization.
{"title":"Laser solder ball jetting of SAC305/ENIG joints: Microstructure, kinetics, and reliability under multiple reflow cycles","authors":"Seungchan Ka , Deborah Bae , Ashutosh Sharma , Jae Pil Jung , Hyun-Sik Kim","doi":"10.1016/j.intermet.2025.109098","DOIUrl":"10.1016/j.intermet.2025.109098","url":null,"abstract":"<div><div>In this work, laser solder ball jetting (LSBJ) was used to bond electroless nickel immersion gold (ENIG) coated Cu pads on FR4 substrates. Lead-free SAC305 (Sn–3Ag–0.5Cu) solder balls (Ф 100 μm) were used for the LSBJ process. After LSBJ, the solder joints were reflowed for various reflow cycles (0, 1, 3, 5, and 7), each cycle consisting of 60 s. The microstructure and mechanical properties of the LSBJ solder joints so formed were studied after multiple reflow cycles. It was found that SAC/ENIG-Cu solder joints had higher shearing strength during multiple reflows. The shearing force of the solder joints remained almost stable with the increase in the number of reflow cycles. The fracture of SAC/ENIG-Cu solder joints in LSBJ (before reflow) mainly occurred in the bulk solder. In contrast, after reflow, it showed various combinations of bulk solder fracture, ball lift, and Cu-pad lift interface failure. The microstructure evolution of the solder joints during multiple reflows showed a continuous change in the chemical composition of the IMC layer. Large Ag–Sn and Cu<sub>6</sub>Sn<sub>5</sub> phases near the IMC layer were found within the SAC solder joints on the Cu pads. The LSBJ process enables precise solder deposition and uniform bonding quality during initial joining; however, multiple reflow cycles can lead to progressive IMC growth, affecting long-term reliability. These results demonstrate that while LSBJ offers distinct advantages in controlled soldering, its performance stability under multiple reflows requires further optimization.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109098"},"PeriodicalIF":4.8,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-28DOI: 10.1016/j.intermet.2025.109109
Piotr Konieczny , Dominik Czernia , Stanisław M. Dubiel
A series of three sigma-phase Fe-Cr-Ni intermetallic compounds — Fe45.8Cr49Ni5.2, Fe50.7Cr46.7Ni2.6, and Fe52.5Cr45.55Ni1.95 — were systematically studied using ac and dc magnetic susceptibility measurements to construct their respective magnetic phase diagrams in the temperature-field (H-T) space. These compounds, characterized by increasing Fe content and decreasing Cr and Ni content, all exhibit ferrimagnetic ordering below their critical temperatures (Tc), accompanied by significantly negative Curie-Weiss temperatures (θ = −461(22) K, −155(6) K, and −134(11) K, respectively), indicating strong antiferromagnetic interactions. A re-entrant magnetic behavior was observed in all samples, transitioning into a spin-glass state at lower temperatures. The degree of magnetic frustration, quantified by the degree of frustration (DOF), was found to increase with Cr and Ni content, peaking at DOF = 34 for Fe45.8Cr49Ni5.2. The spin-glass state exhibits heterogeneity, comprising two substates with weak and strong irreversibility. The share of the spin-glass phase in the magnetic phase diagram diminishes as the Cr and Ni content increases. Analysis of the relative shift of the spin freezing temperature per decade of frequency, confirms that all compounds exhibit cluster spin-glass behavior.
{"title":"Tuning magnetic frustration via composition: Spin-glass dynamics and phase diagrams of sigma-phase Fe–Cr–Ni alloys","authors":"Piotr Konieczny , Dominik Czernia , Stanisław M. Dubiel","doi":"10.1016/j.intermet.2025.109109","DOIUrl":"10.1016/j.intermet.2025.109109","url":null,"abstract":"<div><div>A series of three sigma-phase Fe-Cr-Ni intermetallic compounds — Fe<sub>45.8</sub>Cr<sub>49</sub>Ni<sub>5.2</sub>, Fe<sub>50.7</sub>Cr<sub>46.7</sub>Ni<sub>2.6</sub>, and Fe<sub>52.5</sub>Cr<sub>45.55</sub>Ni<sub>1.95</sub> — were systematically studied using ac and dc magnetic susceptibility measurements to construct their respective magnetic phase diagrams in the temperature-field (<em>H</em>-<em>T</em>) space. These compounds, characterized by increasing Fe content and decreasing Cr and Ni content, all exhibit ferrimagnetic ordering below their critical temperatures (<em>T</em><sub>c</sub>), accompanied by significantly negative Curie-Weiss temperatures (<em>θ</em> = −461(22) K, −155(6) K, and −134(11) K, respectively), indicating strong antiferromagnetic interactions. A re-entrant magnetic behavior was observed in all samples, transitioning into a spin-glass state at lower temperatures. The degree of magnetic frustration, quantified by the degree of frustration (DOF), was found to increase with Cr and Ni content, peaking at DOF = 34 for Fe<sub>45.8</sub>Cr<sub>49</sub>Ni<sub>5.2</sub>. The spin-glass state exhibits heterogeneity, comprising two substates with weak and strong irreversibility. The share of the spin-glass phase in the magnetic phase diagram diminishes as the Cr and Ni content increases. Analysis of the relative shift of the spin freezing temperature per decade of frequency, confirms that all compounds exhibit cluster spin-glass behavior.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109109"},"PeriodicalIF":4.8,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The foundational concept of high-entropy alloys (HEAs) posits that enhanced configurational entropy serves as the dominant factor stabilizing single-phase solid solutions in concentrated metallic systems. However, extensive experimental studies reveal significant contradictions to this paradigm — the presence of multiple constituent elements neither guarantees single-phase formation nor ensures exceptional thermal stability. These alloys, typically synthesized via arc-melting techniques, actually represent metastable high-temperature phases that exhibit instability under varying thermal conditions. Despite their metastable nature, such non-equilibrium crystalline structures demonstrate remarkable functional properties compared to conventional materials, driving substantial interdisciplinary research interest from both fundamental and applied perspectives. Prior to practical implementation, comprehensive thermal characterization across wide temperature ranges becomes essential to evaluate their structural integrity and potential functionality. This investigation systematically examines thermal evolution and crystalline anisotropy effects in the body-centered cubic (BCC) phase of TiVNbMo HEA through complementary approaches: in situ high-temperature X-ray diffraction experiments and advanced first-principles atomistic simulations employing graph neural network-based universal interatomic potentials. Our results demonstrate that the quenched BCC structure remains stable only up to 770 K, beyond which the alloy undergoes successive structural transformations. A particularly significant finding concerns anomalous anisotropic thermal expansion behavior of the BCC phase along different crystallographic axes. This unexpected phenomenon in a cubic system arises from the combined effects of lattice defectivity and pronounced elastic anisotropy, which likely contribute to the material’s thermal instability. Using a semi-quantitative model that combines quasi-harmonic lattice dynamics with anharmonic contributions of higher order, we demonstrate that elastic softness directly enhances thermal expansion along specific crystallographic axes. These observations provide new insights into the fundamental relationships between structural defects, elastic anisotropy, and thermal stability in complex concentrated alloys.
{"title":"Unraveling thermal evolution and anisotropy in BCC TiVNbMo high entropy alloy via in situ XRD and first-principles simulations","authors":"S.A. Uporov , V.S. Gaviko , V.G. Pushin , L.A. Cherepanova , E.O. Khazieva , V.A. Bykov , N.N. Katkov , R.E. Ryltsev","doi":"10.1016/j.intermet.2025.109092","DOIUrl":"10.1016/j.intermet.2025.109092","url":null,"abstract":"<div><div>The foundational concept of high-entropy alloys (HEAs) posits that enhanced configurational entropy serves as the dominant factor stabilizing single-phase solid solutions in concentrated metallic systems. However, extensive experimental studies reveal significant contradictions to this paradigm — the presence of multiple constituent elements neither guarantees single-phase formation nor ensures exceptional thermal stability. These alloys, typically synthesized via arc-melting techniques, actually represent metastable high-temperature phases that exhibit instability under varying thermal conditions. Despite their metastable nature, such non-equilibrium crystalline structures demonstrate remarkable functional properties compared to conventional materials, driving substantial interdisciplinary research interest from both fundamental and applied perspectives. Prior to practical implementation, comprehensive thermal characterization across wide temperature ranges becomes essential to evaluate their structural integrity and potential functionality. This investigation systematically examines thermal evolution and crystalline anisotropy effects in the body-centered cubic (BCC) phase of TiVNbMo HEA through complementary approaches: <em>in situ</em> high-temperature X-ray diffraction experiments and advanced first-principles atomistic simulations employing graph neural network-based universal interatomic potentials. Our results demonstrate that the quenched BCC structure remains stable only up to 770 K, beyond which the alloy undergoes successive structural transformations. A particularly significant finding concerns anomalous anisotropic thermal expansion behavior of the BCC phase along different crystallographic axes. This unexpected phenomenon in a cubic system arises from the combined effects of lattice defectivity and pronounced elastic anisotropy, which likely contribute to the material’s thermal instability. Using a semi-quantitative model that combines quasi-harmonic lattice dynamics with anharmonic contributions of higher order, we demonstrate that elastic softness directly enhances thermal expansion along specific crystallographic axes. These observations provide new insights into the fundamental relationships between structural defects, elastic anisotropy, and thermal stability in complex concentrated alloys.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109092"},"PeriodicalIF":4.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper presents a comparative study of two methods for the fabrication of Ni/Al-based metal-intermetallic laminate (MIL) composites within a steel matrix: shock wave loading (SWL) and a combined SWL/heat treatment (HT) method. Initiating the reaction in self-propagating high-temperature synthesis (SHS) mode under shock wave loading resulted in the formation of an intermetallic layer (IL) with an average microhardness of 500 HV. This IL exhibited both non-uniform thickness and cracking. The reaction initiated at the sample's end, where conditions conducive to SHS were established, and then propagated towards the top. At the top of the sample, the reaction products were quenched because heat removal exceeded heat generation. The two-step SWL/HT method ensured the formation of a multiphase IL (NiAl, Ni2Al3, Ni3Al) without cracks, but it was accompanied by gas evolution, causing deformation and delamination. The microhardness varied from 370 to 850 HV, with an average of 530 HV. Optimizing the process by removing gases maintained the interface's integrity but resulted in localized transverse cracks. The average microhardness of the IL was 590 HV, with a range of 450–900 HV. The heating rate during HT significantly affected the completeness of the transformation: slow heating (11.5 °C/min) promoted more complete NiAl formation compared to rapid heating (23 °C/min). Recommendations for minimizing defects in each method were developed. The results obtained are of interest for fabricating composites with improved mechanical and thermal properties, which are in demand in the aerospace and energy industries.
{"title":"Study of microstructural evolution in NiAl-Steel laminate composite after shock wave loading and heat treatment","authors":"A. Yu Malakhov , S.A. Seropyan , I.V. Denisov , I.V. Saikov , D.V. Shakhray","doi":"10.1016/j.intermet.2025.109097","DOIUrl":"10.1016/j.intermet.2025.109097","url":null,"abstract":"<div><div>The paper presents a comparative study of two methods for the fabrication of Ni/Al-based metal-intermetallic laminate (MIL) composites within a steel matrix: shock wave loading (SWL) and a combined SWL/heat treatment (HT) method. Initiating the reaction in self-propagating high-temperature synthesis (SHS) mode under shock wave loading resulted in the formation of an intermetallic layer (IL) with an average microhardness of 500 HV. This IL exhibited both non-uniform thickness and cracking. The reaction initiated at the sample's end, where conditions conducive to SHS were established, and then propagated towards the top. At the top of the sample, the reaction products were quenched because heat removal exceeded heat generation. The two-step SWL/HT method ensured the formation of a multiphase IL (NiAl, Ni<sub>2</sub>Al<sub>3</sub>, Ni<sub>3</sub>Al) without cracks, but it was accompanied by gas evolution, causing deformation and delamination. The microhardness varied from 370 to 850 HV, with an average of 530 HV. Optimizing the process by removing gases maintained the interface's integrity but resulted in localized transverse cracks. The average microhardness of the IL was 590 HV, with a range of 450–900 HV. The heating rate during HT significantly affected the completeness of the transformation: slow heating (11.5 °C/min) promoted more complete NiAl formation compared to rapid heating (23 °C/min). Recommendations for minimizing defects in each method were developed. The results obtained are of interest for fabricating composites with improved mechanical and thermal properties, which are in demand in the aerospace and energy industries.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109097"},"PeriodicalIF":4.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-27DOI: 10.1016/j.intermet.2025.109067
Yupeng Cao , Yingxian Ma , Shicheng Wei , Bo Wang , Haidong Bao , Yujiang Wang , Rui Zhou
The microstructure and wear properties of (AlxCoCrFeNi)N0.5 (x = 0.3, 0.5, 0.7) high-entropy alloy thin films deposited on the surface of E690 steel by magnetron sputtering were investigated herein. Transmission electron microscopy combined with energy-dispersive spectroscopy was employed to analyze the microstructural evolution and formation mechanisms. Scanning electron microscopy was coupled with nanoindentation and friction-wear tests to evaluate the effects of the microstructure on the properties (i.e., hardness, elastic modulus, friction coefficient, and wear rate). Finally, a conceptual model of the underlying physical phenomena was proposed to illustrate the observations and explain the relationship between the microstructure and wear properties. The results indicated that increasing the Al content promotes amorphous transformation in the films. When x = 0.5, the film exhibited a nanocrystalline-amorphous dual-phase structure, which alleviated agglomeration and promoted film growth. The (Al0.5CoCrFeNi)N0.5 film exhibited the highest average thickness (2.73 μm), as well as the highest hardness and elastic modulus (9.54 and 187.76 GPa, respectively), at this time, the wear performance is also the best, and the friction coefficient and wear rate are 0.101 and 0.739 × 10−15 m3/(N·m) respectively, which are reduced by 64.4 % and 54.4 % compared with the substrate; under the given deposition conditions. Ultimately, an appropriate mixture of nanocrystalline and amorphous regions can hinder dislocation movement and grain rotation, inhibit grain boundary sliding, and improve the wear resistance of the film. The research results provide insights for the preparation of dual-phase high-entropy alloy thin films with high wear resistance.
{"title":"Microstructure and wear properties of (AlxCoCrFeNi)N0.5 dual-phase high-entropy alloy thin films prepared by magnetron sputtering","authors":"Yupeng Cao , Yingxian Ma , Shicheng Wei , Bo Wang , Haidong Bao , Yujiang Wang , Rui Zhou","doi":"10.1016/j.intermet.2025.109067","DOIUrl":"10.1016/j.intermet.2025.109067","url":null,"abstract":"<div><div>The microstructure and wear properties of (Al<sub>x</sub>CoCrFeNi)N<sub>0.5</sub> (x = 0.3, 0.5, 0.7) high-entropy alloy thin films deposited on the surface of E690 steel by magnetron sputtering were investigated herein. Transmission electron microscopy combined with energy-dispersive spectroscopy was employed to analyze the microstructural evolution and formation mechanisms. Scanning electron microscopy was coupled with nanoindentation and friction-wear tests to evaluate the effects of the microstructure on the properties (i.e., hardness, elastic modulus, friction coefficient, and wear rate). Finally, a conceptual model of the underlying physical phenomena was proposed to illustrate the observations and explain the relationship between the microstructure and wear properties. The results indicated that increasing the Al content promotes amorphous transformation in the films. When x = 0.5, the film exhibited a nanocrystalline-amorphous dual-phase structure, which alleviated agglomeration and promoted film growth. The (Al<sub>0.5</sub>CoCrFeNi)N<sub>0.5</sub> film exhibited the highest average thickness (2.73 μm), as well as the highest hardness and elastic modulus (9.54 and 187.76 GPa, respectively), at this time, the wear performance is also the best, and the friction coefficient and wear rate are 0.101 and 0.739 × 10<sup>−15</sup> m<sup>3</sup>/(N·m) respectively, which are reduced by 64.4 % and 54.4 % compared with the substrate; under the given deposition conditions. Ultimately, an appropriate mixture of nanocrystalline and amorphous regions can hinder dislocation movement and grain rotation, inhibit grain boundary sliding, and improve the wear resistance of the film. The research results provide insights for the preparation of dual-phase high-entropy alloy thin films with high wear resistance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"189 ","pages":"Article 109067"},"PeriodicalIF":4.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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