Pub Date : 2025-12-23DOI: 10.1016/j.ijrmhm.2025.107641
Zhaoyang Liu , Qingqun Liu
Submicron TiC particles reinforced Inconel 625 (TiC/IN625) metal matrix composites were additively fabricated by laser direct energy deposition. The effect of nanoprecipitations on microstructure evolution, mechanical properties and corrosion resistance of the TiC/IN625 composites were studied. The results showed that the TiC particles completely decomposed into Ti and C atoms, and reprecipitated in the form of MC (M = Ti, Mo, Nb) carbides and Al2O3-MC core-shell nanogranules, contributing to the grain refinement and dramatic dislocation multiplication and pile-up. Due to the synergistic strengthening effect of nanoprecipitations including Al2O3 oxides, MC carbides, Al2O3-MC core-shell nanogranules and Laves phase, along with the solution strengthening effect of the Ti atoms in IN625 matrix and grain refinement, the microhardness was significantly improved from 267 HV to 331 HV with the increasing TiC content from 0.0 to 3.5 wt%, and the ultimate tensile strength increased from 829.1 MPa to 1020.9 MPa with a synchronous deterioration of elongation from 53.6 % to 19.3 %. The corrosion resistance was deteriorated by aggravated pit corrosions around these increased MC carbides and Al2O3-MC core-shell nanogranules in comparison to pure IN625 alloy. The wear resistance was significantly improved by the increasing TiC content. The friction coefficient and wear rate achieved the minimum values of 0.59 and 4.23 × 10−5 mm/(N⋅m), respectively.
{"title":"Effects of nanoprecipitations on microstructure evolution, mechanical properties, corrosion and wear resistances of TiC/Inconel 625 metal matrix composites manufactured by laser direct energy deposition","authors":"Zhaoyang Liu , Qingqun Liu","doi":"10.1016/j.ijrmhm.2025.107641","DOIUrl":"10.1016/j.ijrmhm.2025.107641","url":null,"abstract":"<div><div>Submicron TiC particles reinforced Inconel 625 (TiC/IN625) metal matrix composites were additively fabricated by laser direct energy deposition. The effect of nanoprecipitations on microstructure evolution, mechanical properties and corrosion resistance of the TiC/IN625 composites were studied. The results showed that the TiC particles completely decomposed into Ti and C atoms, and reprecipitated in the form of <em>M</em>C (<em>M</em> = Ti, Mo, Nb) carbides and Al<sub>2</sub>O<sub>3</sub>-<em>M</em>C core-shell nanogranules, contributing to the grain refinement and dramatic dislocation multiplication and pile-up. Due to the synergistic strengthening effect of nanoprecipitations including Al<sub>2</sub>O<sub>3</sub> oxides, <em>M</em>C carbides, Al<sub>2</sub>O<sub>3</sub>-<em>M</em>C core-shell nanogranules and Laves phase, along with the solution strengthening effect of the Ti atoms in IN625 matrix and grain refinement, the microhardness was significantly improved from 267 HV to 331 HV with the increasing TiC content from 0.0 to 3.5 wt%, and the ultimate tensile strength increased from 829.1 MPa to 1020.9 MPa with a synchronous deterioration of elongation from 53.6 % to 19.3 %. The corrosion resistance was deteriorated by aggravated pit corrosions around these increased <em>M</em>C carbides and Al<sub>2</sub>O<sub>3</sub>-<em>M</em>C core-shell nanogranules in comparison to pure IN625 alloy. The wear resistance was significantly improved by the increasing TiC content. The friction coefficient and wear rate achieved the minimum values of 0.59 and 4.23 × 10<sup>−5</sup> mm/(N⋅m), respectively.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107641"},"PeriodicalIF":4.6,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837170","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 : 2025-12-23DOI: 10.1016/j.ijrmhm.2025.107637
Yinxing Su , Qian Li , Duanwei He , Jiawei Zhang
The widely recognized inverse correlation between hardness and toughness presents a major obstacle to achieving both properties simultaneously, particularly in cemented carbides. Diamond has been regarded as an ideal reinforcing phase for WC-Co composites due to its ultra-high hardness (which enhances overall composite hardness), high bulk modulus (which promotes crack deflection, blunting, and bifurcation thereby improving toughness), and low density (which enables lightweighting). However, under conventional sintering conditions, diamond undergoes severe graphitization, causing its strengthening effect to fail and leading to significant performance loss. In contrast, high-pressure high-temperature (HPHT) sintering fundamentally overcomes this issue: the applied high pressure stabilizes the diamond phase by elevating its graphitization temperature, while simultaneously enhancing interfacial bonding with the WC-Co matrix. By optimizing composition and sintering parameters, a WC-10 vol% Co-50 vol% diamond composite achieved near-full densification (99.02 % relative density), exhibiting high hardness (28.16 GPa), enhanced fracture toughness (14.68 ), good electrical conductivity (), for electrical discharge machining (EDM) capability, and a significantly reduced density of 8.81 g/cm3 (approximately 40 % lighter than conventional WC-Co). This unique composite provides an outstanding balance of performance and lightweight characteristics for advanced applications requiring high strength, toughness, and reduced weight.
{"title":"Lightweight diamond/WC–Co composites achieve synergistic hardness-toughness enhancement via high-pressure sintering","authors":"Yinxing Su , Qian Li , Duanwei He , Jiawei Zhang","doi":"10.1016/j.ijrmhm.2025.107637","DOIUrl":"10.1016/j.ijrmhm.2025.107637","url":null,"abstract":"<div><div>The widely recognized inverse correlation between hardness and toughness presents a major obstacle to achieving both properties simultaneously, particularly in cemented carbides. Diamond has been regarded as an ideal reinforcing phase for WC-Co composites due to its ultra-high hardness (which enhances overall composite hardness), high bulk modulus (which promotes crack deflection, blunting, and bifurcation thereby improving toughness), and low density (which enables lightweighting). However, under conventional sintering conditions, diamond undergoes severe graphitization, causing its strengthening effect to fail and leading to significant performance loss. In contrast, high-pressure high-temperature (HPHT) sintering fundamentally overcomes this issue: the applied high pressure stabilizes the diamond phase by elevating its graphitization temperature, while simultaneously enhancing interfacial bonding with the WC-Co matrix. By optimizing composition and sintering parameters, a WC-10 vol% Co-50 vol% diamond composite achieved near-full densification (99.02 % relative density), exhibiting high hardness (28.16 GPa), enhanced fracture toughness (14.68 <span><math><mi>MPa</mi><mo>∙</mo><msup><mi>m</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span>), good electrical conductivity (<span><math><mn>8.36</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><mspace></mspace><mi>Ω</mi><mo>∙</mo><mi>m</mi></math></span>), for electrical discharge machining (EDM) capability, and a significantly reduced density of 8.81 g/cm<sup>3</sup> (approximately 40 % lighter than conventional WC-Co). This unique composite provides an outstanding balance of performance and lightweight characteristics for advanced applications requiring high strength, toughness, and reduced weight.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107637"},"PeriodicalIF":4.6,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837168","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 : 2025-12-23DOI: 10.1016/j.ijrmhm.2025.107640
Sai Anandhi Seetharaman, Soumyadipta Maiti, Ambesh Gupta, Beena Rai
The yield strength plateau of two BCC refractory high entropy alloys (RHEAs) – MoNbTaVW and MoNbTaW was examined through hybrid Monte Carlo and molecular dynamics (MC/MD) simulations. By analyzing atomic diffusivities derived from vacancy formation and migration energies around the edge dislocation cores, the number of critical atomic swaps were calculated at different temperatures. Using hybrid MC/MD simulations of these critical swaps, we demonstrate that above 1400 K, the stress required to move the dislocations gets saturated, indicating the effect of Dynamic Strain Ageing (DSA) via “cross core motion”. Further simulations on random solid solutions (0 MC swaps) revealed a similar plateau effect at the intermediate temperatures. This was attributed to the additional athermal stress arising from lattice distortions due to solid solution strengthening. Our findings suggest that the yield strength plateau results from an interplay between the DSA-driven diffusion process and athermal stress. Specifically, the plateau emerges from DSA mechanisms in the presence of atomic diffusion, whereas in the absence of diffusion, it is governed by athermal statistical lattice distortions. This dual mechanism framework provides a comprehensive explanation for the experimentally observed Yield strength behavior in RHEAs at intermediate temperatures.
{"title":"Investigating into the mechanisms of high temperature strength of refractory high-entropy alloys","authors":"Sai Anandhi Seetharaman, Soumyadipta Maiti, Ambesh Gupta, Beena Rai","doi":"10.1016/j.ijrmhm.2025.107640","DOIUrl":"10.1016/j.ijrmhm.2025.107640","url":null,"abstract":"<div><div>The yield strength plateau of two BCC refractory high entropy alloys (RHEAs) – MoNbTaVW and MoNbTaW was examined through hybrid Monte Carlo and molecular dynamics (MC/MD) simulations. By analyzing atomic diffusivities derived from vacancy formation and migration energies around the edge dislocation cores, the number of critical atomic swaps were calculated at different temperatures. Using hybrid MC/MD simulations of these critical swaps, we demonstrate that above 1400 K, the stress required to move the dislocations gets saturated, indicating the effect of Dynamic Strain Ageing (DSA) via “cross core motion”. Further simulations on random solid solutions (0 MC swaps) revealed a similar plateau effect at the intermediate temperatures. This was attributed to the additional athermal stress arising from lattice distortions due to solid solution strengthening. Our findings suggest that the yield strength plateau results from an interplay between the DSA-driven diffusion process and athermal stress. Specifically, the plateau emerges from DSA mechanisms in the presence of atomic diffusion, whereas in the absence of diffusion, it is governed by athermal statistical lattice distortions. This dual mechanism framework provides a comprehensive explanation for the experimentally observed Yield strength behavior in RHEAs at intermediate temperatures.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107640"},"PeriodicalIF":4.6,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837091","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}
High-entropy nitrides (HENs) are emerging as next-generation protective coatings that offer superior performance over conventional nitrides on cutting tools. This study explores a new class of HEN coatings with the composition (AlTixNbCrZr)N (x = 0, 0.5, 1), alongside a conventional TiAlN coating, both deposited on cemented carbide substrates via magnetron sputtering. Comprehensive analyses were carried out to evaluate their microstructural characteristics, mechanical and wear properties. The results indicate that both TiAlN and (AlTixNbCrZr)N coatings exhibit a single-phase face-centered cubic (FCC) solid solution. Compared with the conventional TiAlN coating, HEN coatings exhibit significantly enhanced mechanical properties due to intensified Me-N covalent bonding and lattice distortion-induced energy barriers that impede dislocation motion and slip. As the Ti content increased, the (AlTixNbCrZr)N coatings displayed progressive improvements in mechanical performance, reaching a peak hardness of 46.06 GPa. This enhancement is consistent with the inverse Hall-Petch regime for sub-10 nm grain sizes, where grain coarsening enhances hardness by suppressing grain boundary sliding as the dominant deformation mechanism. In terms of wear resistance, the HEN coatings outperformed TiAlN, benefiting from solid solution strengthening driven by high entropy. Among (AlTixNbCrZr)N coatings, (AlTi0.5NbCrZr)N demonstrates optimal wear resistance (wear rate: 4.18 × 10−8 mm3/N·m), attributed to balanced suppression of two failure pathways: (i) excessive abrasive particle formation from low-hardness coatings, and (ii) adhesive wear promoted by elevated Ti content through enhanced material adhesion at the ball-coating interface, leading to accelerated coating tearing failure. The dominant wear mechanisms were identified as adhesive wear and oxidative wear, with slight abrasive wear. These findings offer valuable insights and foundational data for advancing Ti alloy machining technologies.
{"title":"A novel strategy of high-entropy nitride coating for cemented carbide cutting tool: Preparation, microstructure, mechanical and wear properties","authors":"Keke Li, Wenting Shao, Ruilong Wen, Wei Yang, Shangkun Wu, Jian Chen","doi":"10.1016/j.ijrmhm.2025.107644","DOIUrl":"10.1016/j.ijrmhm.2025.107644","url":null,"abstract":"<div><div>High-entropy nitrides (HENs) are emerging as next-generation protective coatings that offer superior performance over conventional nitrides on cutting tools. This study explores a new class of HEN coatings with the composition (AlTi<sub>x</sub>NbCrZr)N (x = 0, 0.5, 1), alongside a conventional TiAlN coating, both deposited on cemented carbide substrates via magnetron sputtering. Comprehensive analyses were carried out to evaluate their microstructural characteristics, mechanical and wear properties. The results indicate that both TiAlN and (AlTi<sub>x</sub>NbCrZr)N coatings exhibit a single-phase face-centered cubic (FCC) solid solution. Compared with the conventional TiAlN coating, HEN coatings exhibit significantly enhanced mechanical properties due to intensified Me-N covalent bonding and lattice distortion-induced energy barriers that impede dislocation motion and slip. As the Ti content increased, the (AlTi<sub>x</sub>NbCrZr)N coatings displayed progressive improvements in mechanical performance, reaching a peak hardness of 46.06 GPa. This enhancement is consistent with the inverse Hall-Petch regime for sub-10 nm grain sizes, where grain coarsening enhances hardness by suppressing grain boundary sliding as the dominant deformation mechanism. In terms of wear resistance, the HEN coatings outperformed TiAlN, benefiting from solid solution strengthening driven by high entropy. Among (AlTi<sub>x</sub>NbCrZr)N coatings, (AlTi<sub>0.5</sub>NbCrZr)N demonstrates optimal wear resistance (wear rate: 4.18 × 10<sup>−8</sup> mm<sup>3</sup>/N·m), attributed to balanced suppression of two failure pathways: (i) excessive abrasive particle formation from low-hardness coatings, and (ii) adhesive wear promoted by elevated Ti content through enhanced material adhesion at the ball-coating interface, leading to accelerated coating tearing failure. The dominant wear mechanisms were identified as adhesive wear and oxidative wear, with slight abrasive wear. These findings offer valuable insights and foundational data for advancing Ti alloy machining technologies.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107644"},"PeriodicalIF":4.6,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837169","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 : 2025-12-22DOI: 10.1016/j.ijrmhm.2025.107642
Ali Fazili, Leila Nikzad, Mansour Razavi
This study presents a comprehensive investigation of the sintering behavior, microstructural evolution, and mechanical properties of (100-xTiCN-xWC)/Co composites fabricated via spark plasma sintering (SPS). Eleven compositions with varying TiCN and WC weight fractions (0–100 wt% WC) were prepared under optimized sintering conditions (1300–1450 °C, 20 MPa, 6 min). X-ray diffraction (XRD) and Rietveld refinement confirmed the retention of the original TiCN, WC, and Co phases without any detectable interdiffusion or secondary phase formation. All samples achieved excellent densification, with relative densities exceeding 98.5 %, demonstrating the effectiveness of SPS in producing fully dense composites.
Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) revealed homogeneous and pore-free microstructures with well-dispersed WC and TiCN phases and a continuous Co binder network. Increasing WC content enhanced sintering kinetics, reduced the shrinkage onset temperature by approximately 100 °C, and promoted uniform densification. Mechanical testing indicated strong compositional dependence of properties. The Vickers hardness (HV10) increased from 14.6 ± 0.53 GPa for TiCN/Co to a maximum of 20.9 ± 0.89 GPa at 60 wt% WC, before slightly declining at higher WC levels. Flexural strength improved steadily with WC addition, reaching 2216 ± 85 MPa for the WC/Co composite. Fracture toughness (K1C) exhibited a non-monotonic trend, decreasing to 9.3 ± 0.7 MPa·m0.5 at 60 wt% WC and recovering to 16.1 ± 0.3 MPa·m0.5 at 100 wt% WC. These findings demonstrate that combining TiCN and WC phases enables precise control over the balance between hardness, toughness, and strength. The hybrid composite with 60 wt% WC exhibited the optimal performance, establishing (TiCN-WC)/Co systems as promising candidates for advanced cutting and wear-resistant applications.
{"title":"Optimization of mechanical properties in hybrid (TiCN-WC)/Co cermets prepared via spark plasma sintering","authors":"Ali Fazili, Leila Nikzad, Mansour Razavi","doi":"10.1016/j.ijrmhm.2025.107642","DOIUrl":"10.1016/j.ijrmhm.2025.107642","url":null,"abstract":"<div><div>This study presents a comprehensive investigation of the sintering behavior, microstructural evolution, and mechanical properties of (100-xTiCN-xWC)/Co composites fabricated via spark plasma sintering (SPS). Eleven compositions with varying TiCN and WC weight fractions (0–100 wt% WC) were prepared under optimized sintering conditions (1300–1450 °C, 20 MPa, 6 min). X-ray diffraction (XRD) and Rietveld refinement confirmed the retention of the original TiCN, WC, and Co phases without any detectable interdiffusion or secondary phase formation. All samples achieved excellent densification, with relative densities exceeding 98.5 %, demonstrating the effectiveness of SPS in producing fully dense composites.</div><div>Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) revealed homogeneous and pore-free microstructures with well-dispersed WC and TiCN phases and a continuous Co binder network. Increasing WC content enhanced sintering kinetics, reduced the shrinkage onset temperature by approximately 100 °C, and promoted uniform densification. Mechanical testing indicated strong compositional dependence of properties. The Vickers hardness (HV10) increased from 14.6 ± 0.53 GPa for TiCN/Co to a maximum of 20.9 ± 0.89 GPa at 60 wt% WC, before slightly declining at higher WC levels. Flexural strength improved steadily with WC addition, reaching 2216 ± 85 MPa for the WC/Co composite. Fracture toughness (K1C) exhibited a non-monotonic trend, decreasing to 9.3 ± 0.7 MPa·m<sup>0.5</sup> at 60 wt% WC and recovering to 16.1 ± 0.3 MPa·m<sup>0.5</sup> at 100 wt% WC. These findings demonstrate that combining TiCN and WC phases enables precise control over the balance between hardness, toughness, and strength. The hybrid composite with 60 wt% WC exhibited the optimal performance, establishing (TiCN-WC)/Co systems as promising candidates for advanced cutting and wear-resistant applications.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107642"},"PeriodicalIF":4.6,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837090","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 : 2025-12-20DOI: 10.1016/j.ijrmhm.2025.107632
Eui Seon Lee, Ji Young Kim, Sung-Tag Oh
The microstructural characteristics and hydrogen reduction behavior of W and W-10 wt% Cu powders have been investigated. These powders are synthesized by ball milling and hydrogen reduction of WO3 and WO3–CuO. The reduction behavior of oxide powders under non-isothermal condition is examined using thermogravimetric analysis at varing heating rates in pure hydrogen atmosphere. After milling for 5 h and hydrogen reduction at 800 °C, the oxide powders were completely converted to W and WCu with an average particle size of about 300 nm. TEM analysis for the reduced WCu powder revealed that nano-sized Cu particles were located on the surface of the coarse W particles. The activation energies for the reduction of pure WO3 and WO3–CuO, estimated by the slope of the Kissinger plot, were measured as 58.9–123.3 kJ/mol depending on reduction steps. In the reduction process of WO2 to W, the WO3-CuO powder mixture exhibited lower activation energy compared to pure WO3 powder. The decrease in activation energy is attributed to the role of pre-reduced Cu particles as nucleation sites for W during the reduction process via chemical vapor transport of WO2(OH)2.
{"title":"Microstructure and non-isothermal reduction behavior of ball-milled WO3-CuO powders in pure hydrogen atmosphere","authors":"Eui Seon Lee, Ji Young Kim, Sung-Tag Oh","doi":"10.1016/j.ijrmhm.2025.107632","DOIUrl":"10.1016/j.ijrmhm.2025.107632","url":null,"abstract":"<div><div>The microstructural characteristics and hydrogen reduction behavior of W and W-10 wt% Cu powders have been investigated. These powders are synthesized by ball milling and hydrogen reduction of WO<sub>3</sub> and WO<sub>3</sub>–CuO. The reduction behavior of oxide powders under non-isothermal condition is examined using thermogravimetric analysis at varing heating rates in pure hydrogen atmosphere. After milling for 5 h and hydrogen reduction at 800 °C, the oxide powders were completely converted to W and W<img>Cu with an average particle size of about 300 nm. TEM analysis for the reduced W<img>Cu powder revealed that nano-sized Cu particles were located on the surface of the coarse W particles. The activation energies for the reduction of pure WO<sub>3</sub> and WO<sub>3</sub>–CuO, estimated by the slope of the Kissinger plot, were measured as 58.9–123.3 kJ/mol depending on reduction steps. In the reduction process of WO<sub>2</sub> to W, the WO<sub>3</sub>-CuO powder mixture exhibited lower activation energy compared to pure WO<sub>3</sub> powder. The decrease in activation energy is attributed to the role of pre-reduced Cu particles as nucleation sites for W during the reduction process via chemical vapor transport of WO<sub>2</sub>(OH)<sub>2</sub>.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107632"},"PeriodicalIF":4.6,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784589","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 : 2025-12-18DOI: 10.1016/j.ijrmhm.2025.107633
Wooseok Jin , Chanseok Moon , Dong-Geun Shin , Jaehan Jung , Doh Hyung Riu
The rapid advancement of hypersonic aerospace technologies greatly demands the development of ultra-high temperature ceramics. Among them, hafnium-based ceramics such as hafnium carbide (HfC) and hafnium carbonitride (HfCxN1-x) are promising candidates due to their high melting points, hardness, and excellent ablation resistance. However, the design and control of polymer-derived precursors for hafnium carbonitride has not been fully researched. Here, we report an aqueous-phase synthesis of HfCxN1-x precursor using ethylenediamine (EDA) in combination with cellulose. EDA, a bidentate ligand, coordinates with Hf as well as cellulose, thus forming polymeric networks and facilitating the generation of an amorphous carbon shell during heat treatment. Notably, induced HfN bonds promotes the intermediate formation of Hf2ON2 and HfN phases hence lowering the energy barrier for HfCxN1-x phase evolution. Finally, HfCxN1-x nanoparticles heat-treated at 1400 °C were sintered at 2100 °C, confirming the sintering feasibility of the aqueous-phase prepared precursors.
{"title":"Aqueous-phase synthesis of hafnium carbonitride precursors via bidentate ligand coordination","authors":"Wooseok Jin , Chanseok Moon , Dong-Geun Shin , Jaehan Jung , Doh Hyung Riu","doi":"10.1016/j.ijrmhm.2025.107633","DOIUrl":"10.1016/j.ijrmhm.2025.107633","url":null,"abstract":"<div><div>The rapid advancement of hypersonic aerospace technologies greatly demands the development of ultra-high temperature ceramics. Among them, hafnium-based ceramics such as hafnium carbide (HfC) and hafnium carbonitride (HfC<sub>x</sub>N<sub>1-x</sub>) are promising candidates due to their high melting points, hardness, and excellent ablation resistance. However, the design and control of polymer-derived precursors for hafnium carbonitride has not been fully researched. Here, we report an aqueous-phase synthesis of HfC<sub>x</sub>N<sub>1-x</sub> precursor using ethylenediamine (EDA) in combination with cellulose. EDA, a bidentate ligand, coordinates with Hf as well as cellulose, thus forming polymeric networks and facilitating the generation of an amorphous carbon shell during heat treatment. Notably, induced Hf<img>N bonds promotes the intermediate formation of Hf<sub>2</sub>ON<sub>2</sub> and HfN phases hence lowering the energy barrier for HfC<sub>x</sub>N<sub>1-x</sub> phase evolution. Finally, HfC<sub>x</sub>N<sub>1-x</sub> nanoparticles heat-treated at 1400 °C were sintered at 2100 °C, confirming the sintering feasibility of the aqueous-phase prepared precursors.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107633"},"PeriodicalIF":4.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784610","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 : 2025-12-18DOI: 10.1016/j.ijrmhm.2025.107636
Lu Wang , Bing-Han Sun , Jian-Jun Yu , Jian-Li Li
In the work, the method of chemical vapor deposition reaction of CO and gaseous MoO3 was proposed to prepare ultrafine Mo2C. Different technologies, such as XRD, FESEM, TEM, laser particle size analysis and Brunauer-Emmett-Teller method, as well as thermodynamic software FactSage 8.3, were adopted to analyze the experimental data. The results revealed that increasing the flow-rate of reduction‑carbonization regent CO (Vouter(CO)) was beneficial for the formation of Mo2C; while when Vouter(CO) exceeded the threshold value, single-phase Mo2C cannot be prepared. The optimal conditions for preparing ultrafine Mo2C were given as T = 1223–1323 K, Vouter(CO) = 900 mL/min, and Vinner(Ar) = 100 mL/min; herein, Vinner(Ar) means the flow-rate of carrier gas Ar. Under these conditions, the preparation procedures of Mo2C followed the pathways of MoO3 → (MoO3)n(n = 2, 3, 4, and 5) → MoO2 → Mo2C. The study also discovered that the as-prepared Mo2C kept the overall morphology as the intermediate product MoO2 with a hexagonal-platelet structure; however, due to the removal of oxygen and the decrease of products' molar volume, the prepared Mo2C exhibited a rougher and more porous micro-structure with a specific surface area up to 36.7 m2/g. This work may provide an important methodical guidance for the scale-preparation of ultrafine Mo2C.
{"title":"A new method for preparing ultrafine Mo2C by the CVD reaction of CO and gaseous MoO3: Parameter optimization and its formation mechanism","authors":"Lu Wang , Bing-Han Sun , Jian-Jun Yu , Jian-Li Li","doi":"10.1016/j.ijrmhm.2025.107636","DOIUrl":"10.1016/j.ijrmhm.2025.107636","url":null,"abstract":"<div><div>In the work, the method of chemical vapor deposition reaction of CO and gaseous MoO<sub>3</sub> was proposed to prepare ultrafine Mo<sub>2</sub>C. Different technologies, such as XRD, FESEM, TEM, laser particle size analysis and Brunauer-Emmett-Teller method, as well as thermodynamic software FactSage 8.3, were adopted to analyze the experimental data. The results revealed that increasing the flow-rate of reduction‑carbonization regent CO (<em>V</em><sub>outer</sub>(CO)) was beneficial for the formation of Mo<sub>2</sub>C; while when <em>V</em><sub>outer</sub>(CO) exceeded the threshold value, single-phase Mo<sub>2</sub>C cannot be prepared. The optimal conditions for preparing ultrafine Mo<sub>2</sub>C were given as <em>T</em> = 1223–1323 K, <em>V</em><sub>outer</sub>(CO) = 900 mL/min, and <em>V</em><sub>inner</sub>(Ar) = 100 mL/min; herein, <em>V</em><sub>inner</sub>(Ar) means the flow-rate of carrier gas Ar. Under these conditions, the preparation procedures of Mo<sub>2</sub>C followed the pathways of MoO<sub>3</sub> → (MoO<sub>3</sub>)<sub><em>n</em></sub>(<em>n</em> = 2, 3, 4, and 5) → MoO<sub>2</sub> → Mo<sub>2</sub>C. The study also discovered that the as-prepared Mo<sub>2</sub>C kept the overall morphology as the intermediate product MoO<sub>2</sub> with a hexagonal-platelet structure; however, due to the removal of oxygen and the decrease of products' molar volume, the prepared Mo<sub>2</sub>C exhibited a rougher and more porous micro-structure with a specific surface area up to 36.7 m<sup>2</sup>/g. This work may provide an important methodical guidance for the scale-preparation of ultrafine Mo<sub>2</sub>C.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107636"},"PeriodicalIF":4.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784611","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 : 2025-12-17DOI: 10.1016/j.ijrmhm.2025.107631
Duwang Liu , Zengbin Yin , Chao Liu , Dongbo Hong
SiC whisker (SiCw)-reinforced α/β-SiAlON ceramic tool materials were fabricated via spark plasma sintering (SPS), and their high-temperature (1000–1400 °C) oxidation behavior and mechanism were studied as compared with pure α/β-SiAlON ceramics. The results showed that the addition of SiCw significantly enhanced the oxidation resistance of SiAlON ceramics, which was attributed to the restriction of the emergence of pores and promotion of scale-like refractory phases formation by SiCw. In addition, the oxidation resistance was decreased with the increase of the α/(α + β) ratio. Diffusion of rare earth cations (Yb3+, Sm3+) and gases (O2, CO, and N2) was the main rate-controlling oxidation mechanisms for α/β-SiAlON ceramic tool materials.
{"title":"High-temperature oxidation behavior and mechanism of α/β-SiAlON ceramic tool materials incorporated with SiC whiskers","authors":"Duwang Liu , Zengbin Yin , Chao Liu , Dongbo Hong","doi":"10.1016/j.ijrmhm.2025.107631","DOIUrl":"10.1016/j.ijrmhm.2025.107631","url":null,"abstract":"<div><div>SiC whisker (SiC<sub>w</sub>)-reinforced α/β-SiAlON ceramic tool materials were fabricated via spark plasma sintering (SPS), and their high-temperature (1000–1400 °C) oxidation behavior and mechanism were studied as compared with pure α/β-SiAlON ceramics. The results showed that the addition of SiC<sub>w</sub> significantly enhanced the oxidation resistance of SiAlON ceramics, which was attributed to the restriction of the emergence of pores and promotion of scale-like refractory phases formation by SiC<sub>w</sub>. In addition, the oxidation resistance was decreased with the increase of the α/(α + β) ratio. Diffusion of rare earth cations (Yb<sup>3+</sup>, Sm<sup>3+</sup>) and gases (O<sub>2</sub>, CO, and N<sub>2</sub>) was the main rate-controlling oxidation mechanisms for α/β-SiAlON ceramic tool materials.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107631"},"PeriodicalIF":4.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797981","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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