In recent times, dispersion strengthening has been given prime importance by researchers to modify the microstructure and enhance the mechanical properties of tungsten alloys for their applications in strategic sectors. The present study focuses on the incorporation of Y2O3, ZrB2, and graphene nanoplatelet (GNP) in W-0.7Ni-0.3Fe alloys to improve their overall characteristics. To achieve the same, the selected alloy compositions were blended, compacted, and then sintered at 1500 °C for 75 min in H2 atmosphere. It was observed that the addition of nano Y2O3 and GNP increases the sintered density of the WHAs. FESEM and EPMA analysis exhibit the uniform distribution of dispersoids in WHAs. It was noticed that the maximum compressive strength of 1985.6 MPa was obtained in 1 wt% Y2O3 incorporated W-0.7Ni-0.3Fe alloy, followed by Y2O3 + GNP, base alloy, GNP, and ZrB2 incorporated alloys. The maximum bulk hardness of ∼347 HV was obtained in the Y2O3 + GNP incorporated WHAs. Overall, the combined incorporation of Y2O3 and GNP was effective in improving the densification, microstructure and mechanical properties of sintered W-based systems.
{"title":"The effect of ZrB2, Y2O3, and/or graphene nanoplatelet incorporation on densification, microstructural evolution, and compressive deformation of W-0.7Ni-0.3Fe alloys","authors":"Deepak Adhikari , Suvam Sarthak Tripathy , Suresh Chandra Adhikari , Ashirbad Nayak , Alok Kumar Prusty , Tapas Kumar Sahoo , Mayadhar Debata , Pradyut Sengupta","doi":"10.1016/j.ijrmhm.2026.107694","DOIUrl":"10.1016/j.ijrmhm.2026.107694","url":null,"abstract":"<div><div>In recent times, dispersion strengthening has been given prime importance by researchers to modify the microstructure and enhance the mechanical properties of tungsten alloys for their applications in strategic sectors. The present study focuses on the incorporation of Y<sub>2</sub>O<sub>3</sub>, ZrB<sub>2</sub>, and graphene nanoplatelet (GNP) in W-0.7Ni-0.3Fe alloys to improve their overall characteristics. To achieve the same, the selected alloy compositions were blended, compacted, and then sintered at 1500 °C for 75 min in H<sub>2</sub> atmosphere. It was observed that the addition of nano Y<sub>2</sub>O<sub>3</sub> and GNP increases the sintered density of the WHAs. FESEM and EPMA analysis exhibit the uniform distribution of dispersoids in WHAs. It was noticed that the maximum compressive strength of 1985.6 MPa was obtained in 1 wt% Y<sub>2</sub>O<sub>3</sub> incorporated W-0.7Ni-0.3Fe alloy, followed by Y<sub>2</sub>O<sub>3</sub> + GNP, base alloy, GNP, and ZrB<sub>2</sub> incorporated alloys. The maximum bulk hardness of ∼347 HV was obtained in the Y<sub>2</sub>O<sub>3</sub> + GNP incorporated WHAs. Overall, the combined incorporation of Y<sub>2</sub>O<sub>3</sub> and GNP was effective in improving the densification, microstructure and mechanical properties of sintered W-based systems.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107694"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146032954","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 : 2026-08-01Epub Date: 2026-02-12DOI: 10.1016/j.ijrmhm.2026.107727
Pejman Zamani, Meysam Khakian, Saeed Lak, Mohammad Amin Amjadi
The sequence of aging heat treatment for superalloy base metals and the application of hardface coatings pose significant challenges in the refurbishment of gas turbine blades. This study investigates the influence of an aging heat treatment of IN738 superalloy (845 °C, 24 h) on the microstructural features, mechanical characteristics, and tribological performance of HVOF-sprayed Cr₃C₂–NiCr coating. Microstructural and phase analyses were performed utilizing XRD, SEM, and EDS, while microhardness, fracture toughness, and ball-on-disc wear tests were conducted at room temperature and 550 °C. The as-sprayed coating consisted of Cr₃C₂, Cr₇C₃, and NiCr phases, whereas aging promoted the formation of Ni₃Cr, Cr₂₃C₆, and Cr₂O₃ phases through carbide coarsening and oxidation. These transformations resulted in a synergistic effect, leading to approximately a 20% reduction in hardness and a 50% decrease in fracture toughness, accompanied by a moderate increase in wear rate. At room temperature, the as-sprayed and aged coatings exhibited wear rates of 3.1 × 10−15 and 4.1 × 10−15 m3/N·m, respectively, whereas at 550 °C these values decreased to 2.0 × 10−15 and 3.0 × 10−15 m3/N·m. The as-sprayed coating exhibited predominantly abrasive and mild oxidative–adhesive wear, while the aged one showed adhesive transfer and oxide-assisted delamination. The findings suggest that the aging heat treatment of turbine superalloys should precede HVOF coating deposition to maintain the coating's microstructural integrity and high-temperature wear resistance.
{"title":"Correlation between microstructure, phase evolution, and high-temperature wear resistance of HVOF-sprayed Cr3C2-NiCr composite coatings subjected to superalloy aging treatment","authors":"Pejman Zamani, Meysam Khakian, Saeed Lak, Mohammad Amin Amjadi","doi":"10.1016/j.ijrmhm.2026.107727","DOIUrl":"10.1016/j.ijrmhm.2026.107727","url":null,"abstract":"<div><div>The sequence of aging heat treatment for superalloy base metals and the application of hardface coatings pose significant challenges in the refurbishment of gas turbine blades. This study investigates the influence of an aging heat treatment of IN738 superalloy (845 °C, 24 h) on the microstructural features, mechanical characteristics, and tribological performance of HVOF-sprayed Cr₃C₂–NiCr coating. Microstructural and phase analyses were performed utilizing XRD, SEM, and EDS, while microhardness, fracture toughness, and ball-on-disc wear tests were conducted at room temperature and 550 °C. The as-sprayed coating consisted of Cr₃C₂, Cr₇C₃, and NiCr phases, whereas aging promoted the formation of Ni₃Cr, Cr₂₃C₆, and Cr₂O₃ phases through carbide coarsening and oxidation. These transformations resulted in a synergistic effect, leading to approximately a 20% reduction in hardness and a 50% decrease in fracture toughness, accompanied by a moderate increase in wear rate. At room temperature, the as-sprayed and aged coatings exhibited wear rates of 3.1 × 10<sup>−15</sup> and 4.1 × 10<sup>−15</sup> m<sup>3</sup>/N·m, respectively, whereas at 550 °C these values decreased to 2.0 × 10<sup>−15</sup> and 3.0 × 10<sup>−15</sup> m<sup>3</sup>/N·m. The as-sprayed coating exhibited predominantly abrasive and mild oxidative–adhesive wear, while the aged one showed adhesive transfer and oxide-assisted delamination. The findings suggest that the aging heat treatment of turbine superalloys should precede HVOF coating deposition to maintain the coating's microstructural integrity and high-temperature wear resistance.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107727"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171514","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}
Zirconium (Zr) shows great promise for next-generation orthopedic implants due to its excellent biocompatibility, low elastic modulus, and low magnetic susceptibility. However, it is clinically constrained by high production costs and insufficient yield strength. Herein, a novel “impurity utilization + microalloying” strategy is proposed to optimize mechanical properties and reduce costs of Zr-based alloys while preserving biocompatibility and magnetic resonance imaging (MRI) compatibility. By leveraging the β-stabilizing effect of inherent impurities (Hf, Fe) in sponge zirconium (SZr) and atomic mobility inhibition by microalloying elements (Fe, Si, Mg), the brittle ω phase is suppressed in SZr-xNb-0.2 Mg-0.15Fe-0.1Si (SZNx) alloys, promoting formation of the intermediate β' phase (from β → ω transformation). Ultrafine/nanoscale β' plates induce precipitation and boundary strengthening, synergizing with solid solution strengthening from impurities and microalloying elements to enhance strength while maintaining low Young's modulus and good ductility. Consequently, SZNx alloys outperform ZrNb alloys fabricated from high-purity Zr (NZr) or unalloyed SZr in strength. Notably, the Zr-15Nb-0.25 Mg-0.15Fe-0.1Si (SZN15) alloy exhibits exceptional comprehensive properties: Young's modulus (E) = 58 ± 3 GPa, yield strength (YS) = 750 ± 18 MPa, elongation (EL) = 15.5 ± 1.6%. In vitro biocompatibility assessments show SZN15 cell viability exceeds 92% over all test periods, comparable to or better than clinically used Ti–6Al–4 V (TC4) and NZr. The mass magnetic susceptibility of SZNx alloys (1.27–1.90 × 10−6 cm3/g) is ∼50% that of TC4, ensuring excellent MRI compatibility. Most importantly, the cost of SZNx alloys is reduced by over 80% versus NZr-based alloys. This work offers an efficient, cost-effective strategy for developing low-cost, high-performance Zr-based orthopedic alloys, addressing the strength-modulus-ductility trade-off and cost barriers limiting clinical translation. .
{"title":"Optimization of mechanical properties and cost-reduction of potential orthopedic Zr alloys maintaining favorable biocompatibility through impurity utilization and microalloying","authors":"X.K. Liu , Z.C. Yin , S.X. Liang, Z.K. Zhou, Z.Y. Yuan, B.Y. Liu, Y.X. Guo, S.Z. Zhang, J.S. Zhang, X.Y. Zhang, R.P. Liu","doi":"10.1016/j.ijrmhm.2026.107687","DOIUrl":"10.1016/j.ijrmhm.2026.107687","url":null,"abstract":"<div><div>Zirconium (Zr) shows great promise for next-generation orthopedic implants due to its excellent biocompatibility, low elastic modulus, and low magnetic susceptibility. However, it is clinically constrained by high production costs and insufficient yield strength. Herein, a novel “impurity utilization + microalloying” strategy is proposed to optimize mechanical properties and reduce costs of Zr-based alloys while preserving biocompatibility and magnetic resonance imaging (MRI) compatibility. By leveraging the β-stabilizing effect of inherent impurities (Hf, Fe) in sponge zirconium (SZr) and atomic mobility inhibition by microalloying elements (Fe, Si, Mg), the brittle ω phase is suppressed in SZr-xNb-0.2 Mg-0.15Fe-0.1Si (SZNx) alloys, promoting formation of the intermediate β' phase (from β → ω transformation). Ultrafine/nanoscale β' plates induce precipitation and boundary strengthening, synergizing with solid solution strengthening from impurities and microalloying elements to enhance strength while maintaining low Young's modulus and good ductility. Consequently, SZNx alloys outperform Zr<img>Nb alloys fabricated from high-purity Zr (NZr) or unalloyed SZr in strength. Notably, the Zr-15Nb-0.25 Mg-0.15Fe-0.1Si (SZN15) alloy exhibits exceptional comprehensive properties: Young's modulus (E) = 58 ± 3 GPa, yield strength (YS) = 750 ± 18 MPa, elongation (EL) = 15.5 ± 1.6%. In vitro biocompatibility assessments show SZN15 cell viability exceeds 92% over all test periods, comparable to or better than clinically used Ti–6Al–4 V (TC4) and NZr. The mass magnetic susceptibility of SZNx alloys (1.27–1.90 × 10<sup>−6</sup> cm<sup>3</sup>/g) is ∼50% that of TC4, ensuring excellent MRI compatibility. Most importantly, the cost of SZNx alloys is reduced by over 80% versus NZr-based alloys. This work offers an efficient, cost-effective strategy for developing low-cost, high-performance Zr-based orthopedic alloys, addressing the strength-modulus-ductility trade-off and cost barriers limiting clinical translation.<!--> <!-->.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107687"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057556","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 : 2026-08-01Epub Date: 2026-01-22DOI: 10.1016/j.ijrmhm.2026.107691
Ruochong Wang , Yunan Fan , Zihan Yang , Weiwei He , Li Wang , Bin Liu , Yang Lu , Yong Liu
The influences of printing process on metallurgical quality and wear resistance of NiCu-diamond composites were quantitatively analyzed. The NiCu-diamond composite with low porosity (∼1.6 vol%) and low loss of diamond particles (only 0.5 vol%) was successfully fabricated, at an electron beam current of 2.4 mA, and a scanning rate of 1 m·s−1. The wear rate of the NiCu-diamond composite was as low as 5.0 × 10−7 mm3·N−1·m−1, and coefficients of friction (COFs) within 0.02–0.05. These values represent a substantial reduction compared to the corresponding values of 43.7 × 10−7 mm3·N−1·m−1 and 0.18–0.28. The dense tribofilm formed during wet friction (in 3.5 wt% NaCl solution) hinders further wear of the substrate, leading to lower COFs and wear rates than those of dry friction. The PBF-ed NiCu-diamond composites show excellent wet friction and wear properties with COFs lower than 0.04 and a wear rate of 1.6 × 10−7 mm3·N−1·m−1.
{"title":"Friction and wear behavior of NiCu-diamond composites fabricated by defect-controlled powder bed fusion (PBF) process","authors":"Ruochong Wang , Yunan Fan , Zihan Yang , Weiwei He , Li Wang , Bin Liu , Yang Lu , Yong Liu","doi":"10.1016/j.ijrmhm.2026.107691","DOIUrl":"10.1016/j.ijrmhm.2026.107691","url":null,"abstract":"<div><div>The influences of printing process on metallurgical quality and wear resistance of NiCu-diamond composites were quantitatively analyzed. The NiCu-diamond composite with low porosity (∼1.6 vol%) and low loss of diamond particles (only 0.5 vol%) was successfully fabricated, at an electron beam current of 2.4 mA, and a scanning rate of 1 m·s<sup>−1</sup>. The wear rate of the NiCu-diamond composite was as low as 5.0 × 10<sup>−7</sup> mm<sup>3</sup>·N<sup>−1</sup>·m<sup>−1</sup>, and coefficients of friction (COFs) within 0.02–0.05. These values represent a substantial reduction compared to the corresponding values of 43.7 × 10<sup>−7</sup> mm<sup>3</sup>·N<sup>−1</sup>·m<sup>−1</sup> and 0.18–0.28. The dense tribofilm formed during wet friction (in 3.5 wt% NaCl solution) hinders further wear of the substrate, leading to lower COFs and wear rates than those of dry friction. The PBF-ed NiCu-diamond composites show excellent wet friction and wear properties with COFs lower than 0.04 and a wear rate of 1.6 × 10<sup>−7</sup> mm<sup>3</sup>·N<sup>−1</sup>·m<sup>−1</sup>.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107691"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146032957","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 : 2026-08-01Epub Date: 2026-02-11DOI: 10.1016/j.ijrmhm.2026.107732
Xiya He, Xiping Guo, Ying Li, Chenyu Hu
Five multi-elemental NbSi based ultrahigh temperature alloys with nominal compositions of Nb-22Ti-14.8Si-4Cr-2.5Al-xCo (x = 0, 1, 2, 4, and 8 at.%) were prepared via vacuum non-consumable arc-melting. The effects of Co addition on the microstructure, nanoindentation hardness, compressive strength and isothermal oxidation resistance at 1250 °C of the alloys were investigated. The results reveal that the content of both the Nbss/γ(Nb,X)5Si3 eutectic and the Nbss phase decreases with increasing Co content in the alloys and Co addition promotes the morphological transformation of Nbss toward a dendritic structure. Meanwhile, the addition of Co promotes the formation of new polymorphs of silicide phases; the increase in Co content changes the phase fractions of the alloys. In alloys with 0, 1, and 2 at.% Co, the only silicide phase is γ(Nb,X)5Si3, but in alloys with Co content above 2 at.%, two other types of silicide phases (α(Nb,X)5Si3 and β(Nb,X)5Si3) also exist except for γ(Nb,X)5Si3. Furthermore, Co addition promotes the formation of low-melting-point phases such as Cr2(Nb,X), Tiss and Ti2Co between Nbss/γ(Nb,X)5Si3 eutectic cells and along the Nbss boundaries, which degrades the compressive strength at 1250 °C of the alloys. However, Co addition increases the nanoindentation hardness of both Nbss and γ(Nb,X)5Si3 due to the solid solution strengthening effect of Co. The addition of Co has no significant effect on the oxidation resistance at 1250 °C of the alloys.
{"title":"Effects of Co addition on the microstructure and properties of multi-elemental NbSi based ultrahigh temperature alloys","authors":"Xiya He, Xiping Guo, Ying Li, Chenyu Hu","doi":"10.1016/j.ijrmhm.2026.107732","DOIUrl":"10.1016/j.ijrmhm.2026.107732","url":null,"abstract":"<div><div>Five multi-elemental Nb<img>Si based ultrahigh temperature alloys with nominal compositions of Nb-22Ti-14.8Si-4Cr-2.5Al-xCo (x = 0, 1, 2, 4, and 8 at.%) were prepared via vacuum non-consumable arc-melting. The effects of Co addition on the microstructure, nanoindentation hardness, compressive strength and isothermal oxidation resistance at 1250 °C of the alloys were investigated. The results reveal that the content of both the Nbss/γ(Nb,X)<sub>5</sub>Si<sub>3</sub> eutectic and the Nbss phase decreases with increasing Co content in the alloys and Co addition promotes the morphological transformation of Nbss toward a dendritic structure. Meanwhile, the addition of Co promotes the formation of new polymorphs of silicide phases; the increase in Co content changes the phase fractions of the alloys. In alloys with 0, 1, and 2 at.% Co, the only silicide phase is γ(Nb,X)<sub>5</sub>Si<sub>3</sub>, but in alloys with Co content above 2 at.%, two other types of silicide phases (α(Nb,X)<sub>5</sub>Si<sub>3</sub> and β(Nb,X)<sub>5</sub>Si<sub>3</sub>) also exist except for γ(Nb,X)<sub>5</sub>Si<sub>3</sub>. Furthermore, Co addition promotes the formation of low-melting-point phases such as Cr<sub>2</sub>(Nb,X), Tiss and Ti<sub>2</sub>Co between Nbss/γ(Nb,X)<sub>5</sub>Si<sub>3</sub> eutectic cells and along the Nbss boundaries, which degrades the compressive strength at 1250 °C of the alloys. However, Co addition increases the nanoindentation hardness of both Nbss and γ(Nb,X)<sub>5</sub>Si<sub>3</sub> due to the solid solution strengthening effect of Co. The addition of Co has no significant effect on the oxidation resistance at 1250 °C of the alloys.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107732"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160482","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 : 2026-08-01Epub Date: 2026-02-11DOI: 10.1016/j.ijrmhm.2026.107730
Xinu Tan , Yushun Liu , Risheng Qiu , Xuan Zhang , Liang Zhang , Jiateng Ma , Wangrui Ren , Feitao Li
Two types of orientation relationship (OR) Burgers and Potter can be observed during the phase transformation between the α and β phases in Zr alloys. In this work, electron back scatter diffraction and high-resolution transmission electron microscopy were carried out to characterize Potter OR in the solution-treated and subsequently annealed Zr alloys. Our results reveal the presence of Potter OR between parent β-Zr and {101}α twinning Martensite, elucidating the unique variant selection of {101} twins with in a single α-Zr grain in solution-treated samples. Significantly, a novel, non-stress induced, twinning mechanism was proposed via direct phase transformation based on Potter OR in Martensite. Upon annealing, the OR between β-Zr within the twinning Martensite and α-Zr retains Potter OR, independent of the element segregation at twin boundary. The occurrence of Potter OR instead of Burgers OR is attributed to the lower formation energy of Potter OR upon twinning based on our calculation. These results demonstrate an intrinsic association between Potter OR and the formation of {101} twins, shedding light on the designing of novel high-performance Zr alloys.
{"title":"Potter orientation relationship: The key to the origin of {101¯1} α martensitic twinning and the unusual β precipitation in Zr alloys","authors":"Xinu Tan , Yushun Liu , Risheng Qiu , Xuan Zhang , Liang Zhang , Jiateng Ma , Wangrui Ren , Feitao Li","doi":"10.1016/j.ijrmhm.2026.107730","DOIUrl":"10.1016/j.ijrmhm.2026.107730","url":null,"abstract":"<div><div>Two types of orientation relationship (OR) Burgers and Potter can be observed during the phase transformation between the α and β phases in Zr alloys. In this work, electron back scatter diffraction and high-resolution transmission electron microscopy were carried out to characterize Potter OR in the solution-treated and subsequently annealed Zr alloys. Our results reveal the presence of Potter OR between parent β-Zr and {10<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>1}<sub>α</sub> twinning Martensite, elucidating the unique variant selection of {10<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>1} twins with in a single α-Zr grain in solution-treated samples. Significantly, a novel, non-stress induced, twinning mechanism was proposed via direct phase transformation based on Potter OR in Martensite. Upon annealing, the OR between β-Zr within the twinning Martensite and α-Zr retains Potter OR, independent of the element segregation at twin boundary. The occurrence of Potter OR instead of Burgers OR is attributed to the lower formation energy of Potter OR upon twinning based on our calculation. These results demonstrate an intrinsic association between Potter OR and the formation of {10<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>1} twins, shedding light on the designing of novel high-performance Zr alloys.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107730"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146152749","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 : 2026-08-01Epub Date: 2026-02-05DOI: 10.1016/j.ijrmhm.2026.107722
Tomila M. Vidyuk , Dina V. Dudina , Alexander I. Gavrilov , Arina V. Ukhina , Vladislav S. Shikalov , Igor S. Batraev , Sergey Yu. Usynin , Boris B. Bokhonov
In this study, in situ WC–Cu–based composites containing graphite were fabricated from a mixture of W, C(graphite) and Cu powders by high-energy mechanical milling and subsequent reactive spark plasma sintering (SPS). The synthesis of the carbides occurred during the SPS stage. In order to investigate the effect of graphite concentration on the structure and properties of the composites, the W–C(graphite)–Cu mixtures with three different molar ratios of elements (1:1:3, 1:1.3:3 and 1:1.7:3) were prepared. The graphite not converted into carbides remained unreacted in the sintered compacts. The combination of mechanical milling and SPS resulted in the formation of unconventional microstructures. The Cu-rich regions of re-solidified material are located between the composite areas, in which the WC and W2C particles are distributed uniformly. As the concentration of graphite was increased, the hardness and electrical conductivity of the composites decreased. The concentration of graphite in the composites influenced the morphology of the worn surfaces formed under dry sliding conditions. The WC–W2C–Cu-graphite composite (processing conditions: W–C(graphite)–3Cu mixture, 15 min of milling, SPS at 980 °C) shows an attractive combination of properties: a hardness of 250 HV, an electrical conductivity of 25% of the International Annealed Copper Standard, a residual porosity of less than 5%, a coefficient of friction of 0.58 in a pair with a WC-6Co ball, and a specific wear rate of 0.6 × 10−5 mm3 N−1 m−1.
{"title":"Microstructure and properties of spark plasma sintered WC–Cu–based in situ composites containing graphite","authors":"Tomila M. Vidyuk , Dina V. Dudina , Alexander I. Gavrilov , Arina V. Ukhina , Vladislav S. Shikalov , Igor S. Batraev , Sergey Yu. Usynin , Boris B. Bokhonov","doi":"10.1016/j.ijrmhm.2026.107722","DOIUrl":"10.1016/j.ijrmhm.2026.107722","url":null,"abstract":"<div><div>In this study, in situ WC–Cu–based composites containing graphite were fabricated from a mixture of W, C(graphite) and Cu powders by high-energy mechanical milling and subsequent reactive spark plasma sintering (SPS). The synthesis of the carbides occurred during the SPS stage. In order to investigate the effect of graphite concentration on the structure and properties of the composites, the W–C(graphite)–Cu mixtures with three different molar ratios of elements (1:1:3, 1:1.3:3 and 1:1.7:3) were prepared. The graphite not converted into carbides remained unreacted in the sintered compacts. The combination of mechanical milling and SPS resulted in the formation of unconventional microstructures. The Cu-rich regions of re-solidified material are located between the composite areas, in which the WC and W<sub>2</sub>C particles are distributed uniformly. As the concentration of graphite was increased, the hardness and electrical conductivity of the composites decreased. The concentration of graphite in the composites influenced the morphology of the worn surfaces formed under dry sliding conditions. The WC–W<sub>2</sub>C–Cu-graphite composite (processing conditions: W–C(graphite)–3Cu mixture, 15 min of milling, SPS at 980 °C) shows an attractive combination of properties: a hardness of 250 HV, an electrical conductivity of 25% of the International Annealed Copper Standard, a residual porosity of less than 5%, a coefficient of friction of 0.58 in a pair with a WC-6Co ball, and a specific wear rate of 0.6 × 10<sup>−5</sup> mm<sup>3</sup> N<sup>−1</sup> m<sup>−1</sup>.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107722"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171562","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 : 2026-08-01Epub Date: 2026-01-12DOI: 10.1016/j.ijrmhm.2026.107673
Jun Yang, Yanhang Shi, Liu He, Wei Wang, Guomin Le, Xinjian Zhang
The elevated cost of spherical tantalum powder utilized in additive manufacturing significantly hinders the development and application of tantalum components. In this study, three sets of tantalum thin-wall samples were fabricated using laser melting deposition (LMD) with varying laser power settings, employing non-spherical tantalum powder as the raw material. The samples were analyzed for their scanning electron microscopy (SEM) morphology, phase composition, density, hardness, mechanical properties, and impurity content. The findings indicate that the tantalum components produced via LMD exhibit columnar grains oriented along the deposition direction, achieving a high density of up to 98.7%. The LMD-fabricated tantalum components demonstrate moderate mechanical properties and elongation rate. This study demonstrates that non-spherical tantalum powder can be effectively utilized to produce tantalum components with superior performance through LMD. This approach offers a novel and cost-effective method for the preparation of tantalum components, which holds significant potential for the widespread adoption and application of tantalum.
{"title":"Microstructure and properties of tantalum deposited by laser melting deposition using non-spherical tantalum powder","authors":"Jun Yang, Yanhang Shi, Liu He, Wei Wang, Guomin Le, Xinjian Zhang","doi":"10.1016/j.ijrmhm.2026.107673","DOIUrl":"10.1016/j.ijrmhm.2026.107673","url":null,"abstract":"<div><div>The elevated cost of spherical tantalum powder utilized in additive manufacturing significantly hinders the development and application of tantalum components. In this study, three sets of tantalum thin-wall samples were fabricated using laser melting deposition (LMD) with varying laser power settings, employing non-spherical tantalum powder as the raw material. The samples were analyzed for their scanning electron microscopy (SEM) morphology, phase composition, density, hardness, mechanical properties, and impurity content. The findings indicate that the tantalum components produced via LMD exhibit columnar grains oriented along the deposition direction, achieving a high density of up to 98.7%. The LMD-fabricated tantalum components demonstrate moderate mechanical properties and elongation rate. This study demonstrates that non-spherical tantalum powder can be effectively utilized to produce tantalum components with superior performance through LMD. This approach offers a novel and cost-effective method for the preparation of tantalum components, which holds significant potential for the widespread adoption and application of tantalum.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107673"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956986","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 : 2026-08-01Epub Date: 2026-01-22DOI: 10.1016/j.ijrmhm.2026.107695
José García , Andrei Chychko , Christian Gold
Cemented carbide production is heavily reliant on critical raw materials (CRMs) such as tungsten (W), cobalt (Co), titanium (Ti), tantalum (Ta), niobium (Nb), and ruthenium (Ru), which face increasing supply risks, cost volatility, and environmental challenges. This study presents a sustainable alternative through the design of WC-based cemented carbides reinforced with finely dispersed η-phase carbides. The η-phase morphology and distribution are tailored to substitute conventional γ-phase formers (Ti, Ta, Nb), allowing the replacement of Co binder metal, and minimizing reliance on scarce elements such as Ru. The resulting microstructures exhibit enhanced high-temperature strength, hot hardness, and fracture resistance. Cutting performance tests under severe thermomechanical loading conditions confirm that the new η-phase–reinforced grades offer equivalent or superior performance compared to conventional grades. A detailed Product Carbon Footprint (PCF) analysis demonstrates significantly lower environmental impact and material criticality, establishing η-phase strengthening as a robust strategy for developing next-generation, high-performance cemented carbides with improved sustainability.
硬质合金的生产严重依赖于关键原材料，如钨(W)、钴（Co）、钛（Ti）、钽（Ta）、铌（Nb）和钌（Ru），这些原材料面临着越来越大的供应风险、成本波动和环境挑战。本研究提出了一种可持续的替代方案，即设计以分散良好的η相碳化物为增强材料的wc基硬质合金。η相的形态和分布适合于传统的γ相形成物（Ti, Ta, Nb），允许替代Co结合金属，并最大限度地减少对稀有元素（如Ru）的依赖。由此产生的显微组织表现出增强的高温强度、热硬度和抗断裂性。在严格的热机械载荷条件下的切削性能测试证实，与传统牌号相比，新的η相增强牌号具有同等或更好的性能。一项详细的产品碳足迹（PCF）分析表明，该方法显著降低了对环境的影响和材料的临界性，确立了η相强化作为开发下一代高性能硬质合金的有力策略，并提高了可持续性。
{"title":"Design of novel sustainable cemented carbides strengthened by η-phase to replace critical raw materials","authors":"José García , Andrei Chychko , Christian Gold","doi":"10.1016/j.ijrmhm.2026.107695","DOIUrl":"10.1016/j.ijrmhm.2026.107695","url":null,"abstract":"<div><div>Cemented carbide production is heavily reliant on critical raw materials (CRMs) such as tungsten (W), cobalt (Co), titanium (Ti), tantalum (Ta), niobium (Nb), and ruthenium (Ru), which face increasing supply risks, cost volatility, and environmental challenges. This study presents a sustainable alternative through the design of WC-based cemented carbides reinforced with finely dispersed η-phase carbides. The η-phase morphology and distribution are tailored to substitute conventional γ-phase formers (Ti, Ta, Nb), allowing the replacement of Co binder metal, and minimizing reliance on scarce elements such as Ru. The resulting microstructures exhibit enhanced high-temperature strength, hot hardness, and fracture resistance. Cutting performance tests under severe thermomechanical loading conditions confirm that the new η-phase–reinforced grades offer equivalent or superior performance compared to conventional grades. A detailed Product Carbon Footprint (PCF) analysis demonstrates significantly lower environmental impact and material criticality, establishing η-phase strengthening as a robust strategy for developing next-generation, high-performance cemented carbides with improved sustainability.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107695"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146032955","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 : 2026-08-01Epub Date: 2026-01-30DOI: 10.1016/j.ijrmhm.2026.107713
Chunyan Li , Jie Chen , Andrey Litnovsky , Christian Linsmeier , Shuotong Zong , Yucheng Wu , Xuejiao Wang , Junwei Qiao
Tungsten-based self-passivating metal alloys with reduced thermo-oxidation (SMART), which using Cr or Si as oxidation-resistant elements, have exhibited great potential for oxidation resistance application at high temperature compared with pure W. In this work, aluminum (Al) was added to WCr SMART systems to further improve the oxidation resistance, and the novel W-17.8Cr-6.4Al alloys were successfully developed using spark plasma sintering (SPS) technique. The influence of sintering pressure and temperature on the densification process was systematically investigated, and the oxidation behaviors were studied at 800 °C and 1000 °C. The sintering curves exhibit that there is the liquidation of Al above around 630 °C, and the rapid densification of W-Cr-Al alloys starts above 923–950 °C. The intermetallic compounds of (WCr)Al12 and (WCr)Al4 are generated when sintered at 650 °C and 700 °C, respectively. When sintered above 1000 °C, W-Cr-Al alloys mainly consist of two BCC phases of W-Cr-Al solution. Dense bulk W-Cr-Al alloys, with a density of around 11.6 g/cm3, could be manufactured by sintering above 1200 °C at 20 MPa for 15 min. At the end of oxidation, the oxides formed at 800 °C mainly consist of WO3, Cr2WO6 and Al2W3O12, while WO3 disappears at 1000 °C due to the volatilization of WO3 and the reaction with Cr2O3. In addition, no obvious variation trend of mass gain is observed when oxidized at 800 °C compared with pure W, while a double parabolic trend of mass gain is found during oxidization at 1000 °C. The parabolic oxidation parameter, , is around (7–8) × 10−5 mg2/(cm4min) and (4–5) × 10−4 mg2/(cm4min), respectively. Compared to the linear oxidation behavior of pure W, W-Cr-Al alloys exhibit its potential for oxidation resistance application at high temperature.
{"title":"The development of W-Cr-Al alloys by spark plasma sintering and their oxidation behavior","authors":"Chunyan Li , Jie Chen , Andrey Litnovsky , Christian Linsmeier , Shuotong Zong , Yucheng Wu , Xuejiao Wang , Junwei Qiao","doi":"10.1016/j.ijrmhm.2026.107713","DOIUrl":"10.1016/j.ijrmhm.2026.107713","url":null,"abstract":"<div><div>Tungsten-based self-passivating metal alloys with reduced thermo-oxidation (SMART), which using Cr or Si as oxidation-resistant elements, have exhibited great potential for oxidation resistance application at high temperature compared with pure W. In this work, aluminum (Al) was added to W<img>Cr SMART systems to further improve the oxidation resistance, and the novel W-17.8Cr-6.4Al alloys were successfully developed using spark plasma sintering (SPS) technique. The influence of sintering pressure and temperature on the densification process was systematically investigated, and the oxidation behaviors were studied at 800 °C and 1000 °C. The sintering curves exhibit that there is the liquidation of Al above around 630 °C, and the rapid densification of W-Cr-Al alloys starts above 923–950 °C. The intermetallic compounds of (WCr)Al<sub>12</sub> and (WCr)Al<sub>4</sub> are generated when sintered at 650 °C and 700 °C, respectively. When sintered above 1000 °C, W-Cr-Al alloys mainly consist of two BCC phases of W-Cr-Al solution. Dense bulk W-Cr-Al alloys, with a density of around 11.6 g/cm<sup>3</sup>, could be manufactured by sintering above 1200 °C at 20 MPa for 15 min. At the end of oxidation, the oxides formed at 800 °C mainly consist of WO<sub>3</sub>, Cr<sub>2</sub>WO<sub>6</sub> and Al<sub>2</sub>W<sub>3</sub>O<sub>12</sub>, while WO<sub>3</sub> disappears at 1000 °C due to the volatilization of WO<sub>3</sub> and the reaction with Cr<sub>2</sub>O<sub>3</sub>. In addition, no obvious variation trend of mass gain is observed when oxidized at 800 °C compared with pure W, while a double parabolic trend of mass gain is found during oxidization at 1000 °C. The parabolic oxidation parameter, <span><math><msub><mi>k</mi><mi>p</mi></msub></math></span>, is around (7–8) × 10<sup>−5</sup> mg<sup>2</sup>/(cm<sup>4</sup><span><math><mo>∙</mo></math></span>min) and (4–5) × 10<sup>−4</sup> mg<sup>2</sup>/(cm<sup>4</sup><span><math><mo>∙</mo></math></span>min), respectively. Compared to the linear oxidation behavior of pure W, W-Cr-Al alloys exhibit its potential for oxidation resistance application at high temperature.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107713"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089209","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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