Pub Date : 2024-10-11DOI: 10.1016/j.ijrmhm.2024.106921
Mingxiu Chong , Zhongrong Geng , Guangan Zhang , Xia Li , Xueqian Cao
Repeated contact with high loads can cause damage to the surface of the DLC films and thus affect their fatigue strength. This study systematically investigates the contact fatigue damage of the DLC films with different carbon structures (a-C, a-C:H, and ta-C) by macro-scale cyclic impact tests with alternating loads. The results reveal that the a-C film possesses significantly superior contact fatigue property compared to the a-C:H and ta-C films under high load. The graphitization transformation of the a-C and a-C:H films lead to a decrease in hardness and elastic modulus. The work-hardening of the ta-C films results in an increase in hardness and elastic modulus. The findings indicate that under cyclic load impact conditions, films need a combination of load support and fatigue resistance to achieve optimum lifetime, and solely increasing film hardness could be accompanied by brittle fracture and higher wear.
{"title":"Contact fatigue property of diamond-like carbon films with different structure in cyclic impact conditions","authors":"Mingxiu Chong , Zhongrong Geng , Guangan Zhang , Xia Li , Xueqian Cao","doi":"10.1016/j.ijrmhm.2024.106921","DOIUrl":"10.1016/j.ijrmhm.2024.106921","url":null,"abstract":"<div><div>Repeated contact with high loads can cause damage to the surface of the DLC films and thus affect their fatigue strength. This study systematically investigates the contact fatigue damage of the DLC films with different carbon structures (a-C, a-C:H, and ta-C) by macro-scale cyclic impact tests with alternating loads. The results reveal that the a-C film possesses significantly superior contact fatigue property compared to the a-C:H and ta-C films under high load. The graphitization transformation of the a-C and a-C:H films lead to a decrease in hardness and elastic modulus. The work-hardening of the ta-C films results in an increase in hardness and elastic modulus. The findings indicate that under cyclic load impact conditions, films need a combination of load support and fatigue resistance to achieve optimum lifetime, and solely increasing film hardness could be accompanied by brittle fracture and higher wear.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106921"},"PeriodicalIF":4.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444957","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 : 2024-10-10DOI: 10.1016/j.ijrmhm.2024.106915
O.K. Lepakova, O.A. Shkoda
A method for producing TiB2-Fe composite powder with high performance characteristics has been developed. Optimal modes of self-propagating high-temperature synthesis, grinding of synthesis products and subsequent sintering have been found. The best properties are exhibited by samples sintered from composite powder of the composition TiB2: Fe = 52:48 (wt%) at a sintering temperature of 1400 °C for 60 min. They have a density of 98.2 %, an HRA index of 90 and σ bend = 1200 MPa. The temperature characteristics of synthesis and microstructure of the products have been studied. Mechanical tests of the obtained materials have been carried out and the possibility of its application in the woodworking industry has been shown.
{"title":"TiB2-Fe hard alloys obtained using SHS powders of the Ti-B-Fe system","authors":"O.K. Lepakova, O.A. Shkoda","doi":"10.1016/j.ijrmhm.2024.106915","DOIUrl":"10.1016/j.ijrmhm.2024.106915","url":null,"abstract":"<div><div>A method for producing TiB<sub>2</sub>-Fe composite powder with high performance characteristics has been developed. Optimal modes of self-propagating high-temperature synthesis, grinding of synthesis products and subsequent sintering have been found. The best properties are exhibited by samples sintered from composite powder of the composition TiB<sub>2</sub>: Fe = 52:48 (wt%) at a sintering temperature of 1400 °C for 60 min. They have a density of 98.2 %, an HRA index of 90 and σ <sub>bend</sub> = 1200 MPa. The temperature characteristics of synthesis and microstructure of the products have been studied. Mechanical tests of the obtained materials have been carried out and the possibility of its application in the woodworking industry has been shown.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106915"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433343","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 : 2024-10-10DOI: 10.1016/j.ijrmhm.2024.106916
Vitaliy Kazymyrovych
For cemented carbides, also known as hardmetals, fracture toughness has always been viewed as one of the key properties, which resulted in large amount of research in the subject. This study presents fracture toughness results for 30 cemented carbide grades, covering wide range of microstructures and associated properties. Toughness data was generated at room temperature by three-point bend testing of chevron notched samples. In addition to relatively well studied influences of cobalt content and carbides grain size on fracture toughness, current research also examines impacts of cubic carbides content and alloying elements on material toughness. In this work, traditional “hardness - toughness” diagram is complemented by “coercivity - toughness”, which is shown to be more appropriate for illustration of the detrimental effect that cubic carbides have on fracture toughness. The results presented here also indicate that alloying of binder with Cr or Ru does not have any noticeable effect on room temperature toughness and presence of eta-phase in the microstructure is not necessarily harmful for toughness. In addition, this research illustrates a correlation between fracture toughness and thermal conductivity of cemented carbides. Most importantly, by utilising broad experimental data and regression analysis, an attempt is made to formulate a set of empirical equations that would allow fracture toughness estimate from readily available or easily measurable material parameters. It is shown that fracture toughness of cemented carbides can be predicted with good accuracy from coercivity and cubic carbides content. In addition, regression equations for estimate of hardness and the average carbides grain size are proposed.
{"title":"Fracture toughness of cemented carbides and its correlations with other material properties","authors":"Vitaliy Kazymyrovych","doi":"10.1016/j.ijrmhm.2024.106916","DOIUrl":"10.1016/j.ijrmhm.2024.106916","url":null,"abstract":"<div><div>For cemented carbides, also known as hardmetals, fracture toughness has always been viewed as one of the key properties, which resulted in large amount of research in the subject. This study presents fracture toughness results for 30 cemented carbide grades, covering wide range of microstructures and associated properties. Toughness data was generated at room temperature by three-point bend testing of chevron notched samples. In addition to relatively well studied influences of cobalt content and carbides grain size on fracture toughness, current research also examines impacts of cubic carbides content and alloying elements on material toughness. In this work, traditional “hardness - toughness” diagram is complemented by “coercivity - toughness”, which is shown to be more appropriate for illustration of the detrimental effect that cubic carbides have on fracture toughness. The results presented here also indicate that alloying of binder with Cr or Ru does not have any noticeable effect on room temperature toughness and presence of eta-phase in the microstructure is not necessarily harmful for toughness. In addition, this research illustrates a correlation between fracture toughness and thermal conductivity of cemented carbides. Most importantly, by utilising broad experimental data and regression analysis, an attempt is made to formulate a set of empirical equations that would allow fracture toughness estimate from readily available or easily measurable material parameters. It is shown that fracture toughness of cemented carbides can be predicted with good accuracy from coercivity and cubic carbides content. In addition, regression equations for estimate of hardness and the average carbides grain size are proposed.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106916"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554956","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 : 2024-10-09DOI: 10.1016/j.ijrmhm.2024.106913
Lukas Wimmer , Christian Bienert , Robert Schiftner , Christoph Eisenmenger-Sittner
The microstructure of (doped) tungsten sheets is crucial for their mechanical behavior. Within this study, a new method, based on laser reflection, is proposed to in-situ determine the process of (secondary) recrystallization and the resulting grain size of (doped) tungsten sheets under ultra high vacuum conditions. The system introduced here allows to position the reflection setup at a reasonable distance from the sample to further observe the sample temperature via a pyrometer. The main signals of interest are the reflection intensity, the resulting distribution, and changes thereof. Furthermore, the proposed method can be carried out on polished and as rolled surfaces likewise. This novel method makes it possible to determine the secondary recrystallization temperature () in rolled (K-)doped tungsten sheets within a single non-isothermal annealing procedure. The average surface grain size during isothermal annealing procedures can be evaluated as well. Even though the observations are generally restricted to the surface, in the case of tungsten sheets a sufficient determination of bulk recrystallization kinetics is possible as well. Furthermore, the obtained results show, that the recrystallization temperature can serve as a sufficient measure to describe the recrystallized microstructure. Even for different sample strains, correctly predicts the average grain size resulting for various temperature increase rates. The proposed method provides a simple, coherent, and robust method to evaluate the recrystallization properties of (doped) tungsten sheets within a single measurement.
{"title":"In-situ observation of recrystallization of K-doped tungsten sheets using laser reflection","authors":"Lukas Wimmer , Christian Bienert , Robert Schiftner , Christoph Eisenmenger-Sittner","doi":"10.1016/j.ijrmhm.2024.106913","DOIUrl":"10.1016/j.ijrmhm.2024.106913","url":null,"abstract":"<div><div>The microstructure of (doped) tungsten sheets is crucial for their mechanical behavior. Within this study, a new method, based on laser reflection, is proposed to in-situ determine the process of (secondary) recrystallization and the resulting grain size of (doped) tungsten sheets under ultra high vacuum conditions. The system introduced here allows to position the reflection setup at a reasonable distance from the sample to further observe the sample temperature via a pyrometer. The main signals of interest are the reflection intensity, the resulting distribution, and changes thereof. Furthermore, the proposed method can be carried out on polished and as rolled surfaces likewise. This novel method makes it possible to determine the secondary recrystallization temperature (<span><math><msub><mi>T</mi><msub><mi>R</mi><mi>x</mi></msub></msub></math></span>) in rolled (K-)doped tungsten sheets within a single non-isothermal annealing procedure. The average surface grain size during isothermal annealing procedures can be evaluated as well. Even though the observations are generally restricted to the surface, in the case of tungsten sheets a sufficient determination of bulk recrystallization kinetics is possible as well. Furthermore, the obtained results show, that the recrystallization temperature can serve as a sufficient measure to describe the recrystallized microstructure. Even for different sample strains, <span><math><msub><mi>T</mi><msub><mi>R</mi><mi>x</mi></msub></msub></math></span> correctly predicts the average grain size resulting for various temperature increase rates. The proposed method provides a simple, coherent, and robust method to evaluate the recrystallization properties of (doped) tungsten sheets within a single measurement.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106913"},"PeriodicalIF":4.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.ijrmhm.2024.106914
Zehang Zhuang , Zongbo Li , Leilei Xu , Yan Feng , Richu Wang , Chaoqun Peng
Mechanical alloying was utilized to produce Mo-30Cu(wt%) composite powder. The effects of milling conditions on the powder characteristics and sintering densification were investigated. The morphological evolution during the mechanical alloying process can be categorized into four stages: 1-individual Mo and Cu particles, 2-coexistence of Mo particles and blocky MoCu composite particles, 3-coarse irregular composite particles, and 4-refined near-spherical composite particles or lamellar MoCu composite particles, depending on whether process control agent (PCA) is added. The mechanical alloying degree of the MoCu composite powder was deepened gradually from stage 1 to 4, which is influenced by the ball milling parameters. As the milling speed and milling time increase, the lattice strain and the alloying degree of the MoCu composite powders increase while the grain size of molybdenum particles decreases, which is conducive to accelerating the sintering density. Among these ball milling parameters, an elevated milling speed notably accelerates the mechanical alloying process and the sintering density. Under the milling speed of 600 r/min, ball to powder ratio (BPR) of 10:1, and milling time of 4 h, the grain size, lattice strain, and average particle diameter of the composite powder were measured to be 48.4 nm, 0.247 %, and 21.04 μm, respectively, with the particle morphology being nearly spherical. The sintered density of the MoCu composite reached 98.1 %, larger than the other composites.
{"title":"The influence of ball milling conditions on the powder characteristics and sintering densification of MoCu alloy","authors":"Zehang Zhuang , Zongbo Li , Leilei Xu , Yan Feng , Richu Wang , Chaoqun Peng","doi":"10.1016/j.ijrmhm.2024.106914","DOIUrl":"10.1016/j.ijrmhm.2024.106914","url":null,"abstract":"<div><div>Mechanical alloying was utilized to produce Mo-30Cu(wt%) composite powder. The effects of milling conditions on the powder characteristics and sintering densification were investigated. The morphological evolution during the mechanical alloying process can be categorized into four stages: 1-individual Mo and Cu particles, 2-coexistence of Mo particles and blocky Mo<img>Cu composite particles, 3-coarse irregular composite particles, and 4-refined near-spherical composite particles or lamellar Mo<img>Cu composite particles, depending on whether process control agent (PCA) is added. The mechanical alloying degree of the Mo<img>Cu composite powder was deepened gradually from stage 1 to 4, which is influenced by the ball milling parameters. As the milling speed and milling time increase, the lattice strain and the alloying degree of the Mo<img>Cu composite powders increase while the grain size of molybdenum particles decreases, which is conducive to accelerating the sintering density. Among these ball milling parameters, an elevated milling speed notably accelerates the mechanical alloying process and the sintering density. Under the milling speed of 600 r/min, ball to powder ratio (BPR) of 10:1, and milling time of 4 h, the grain size, lattice strain, and average particle diameter of the composite powder were measured to be 48.4 nm, 0.247 %, and 21.04 μm, respectively, with the particle morphology being nearly spherical. The sintered density of the Mo<img>Cu composite reached 98.1 %, larger than the other composites.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106914"},"PeriodicalIF":4.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419677","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 : 2024-10-05DOI: 10.1016/j.ijrmhm.2024.106912
Dibya Ranjan Behera , P.S. Lin Prakash , Prasun Kundu , Ravi Ranjan Kumar , S.V.S. Narayana Murty , Sujoy Kumar Kar , Sushanta Kumar Panda
Formability study on welded blanks of Nb-based refractory alloy C-103 (Nb-10Hf-1Ti (wt.%)) has tremendous potential for utilizing smaller sheets for realization of large-size divergent portions of upper-stage liquid engine nozzle of satellite launch vehicles and thrusters of attitude orbital control systems. In this work, vacuum-annealed monolithic C-103 sheets were electron beam welded successfully to obtain defect-free welds and detailed microstructural and mechanical characterizations were investigated. Columnar epitaxial grains were found in fusion zone (FZ) instead of equiaxed grains in base metal (BM). Detailed SEM and HRTEM analyses revealed spherical shape of nano-sized HfO2 precipitates with monoclinic crystal structure in the C-103 sheet. Further, microhardness across the weld cross-section indicated that the FZ had a uniform and maximum hardness of ∼195 HV0.5 due to formation of finer nano-sized HfO2 precipitates with higher number density, followed by a lowering of hardness in a narrow heat-affected zone. A marginal reduction in tensile strength of ∼6% with a considerable decrease in ductility of ∼29% was noticed for the welded sample. However, fracture occurred in the BM region, indicating good weld integrity. Furthermore, formability of the welded blanks was evaluated in terms of limiting dome height (LDH), forming limit diagram, and deep drawn cup depth. The effect of the presence of WZ on the formability of the C-103 sheet was estimated under uniaxial, plane strain, and biaxial tensile strain paths for the first time, and the results were compared with the monolithic sample. It was noted that the failure limit of the welded specimens decreased compared to that of the monolithic sample, resulting in a lower LDH of approximately 69% and 62% when deformed along plane strain and biaxial tensile strain paths, respectively. However, a marginal variation in LDH was observed for the uniaxial strain path. Also, the welded blank had more resistance to material flow into the die cavity due to the harder weld region, resulting in a reduction of deep drawn cup depth by 52% than that of the monolithic blank. The overall results concluded that the presence of the WZ significantly affected the formability of the C-103 sheet, especially in plane strain and biaxial strain paths. However, the fracture was never found to be propagating along the weld line, indicating the ability of the weld to sustain large plastic strains. This study provides insightful information on the formability of electron beam welded C-103 sheets for the successful fabrication of space components.
{"title":"Microstructure characterization and formability assessment of electron beam welded Nb-10Hf-1Ti (wt.%) refractory alloy sheets","authors":"Dibya Ranjan Behera , P.S. Lin Prakash , Prasun Kundu , Ravi Ranjan Kumar , S.V.S. Narayana Murty , Sujoy Kumar Kar , Sushanta Kumar Panda","doi":"10.1016/j.ijrmhm.2024.106912","DOIUrl":"10.1016/j.ijrmhm.2024.106912","url":null,"abstract":"<div><div>Formability study on welded blanks of Nb-based refractory alloy C-103 (Nb-10Hf-1Ti (wt.%)) has tremendous potential for utilizing smaller sheets for realization of large-size divergent portions of upper-stage liquid engine nozzle of satellite launch vehicles and thrusters of attitude orbital control systems. In this work, vacuum-annealed monolithic C-103 sheets were electron beam welded successfully to obtain defect-free welds and detailed microstructural and mechanical characterizations were investigated. Columnar epitaxial grains were found in fusion zone (FZ) instead of equiaxed grains in base metal (BM). Detailed SEM and HRTEM analyses revealed spherical shape of nano-sized HfO<sub>2</sub> precipitates with monoclinic crystal structure in the C-103 sheet. Further, microhardness across the weld cross-section indicated that the FZ had a uniform and maximum hardness of ∼195 HV<sub>0.5</sub> due to formation of finer nano-sized HfO<sub>2</sub> precipitates with higher number density, followed by a lowering of hardness in a narrow heat-affected zone. A marginal reduction in tensile strength of ∼6% with a considerable decrease in ductility of ∼29% was noticed for the welded sample. However, fracture occurred in the BM region, indicating good weld integrity. Furthermore, formability of the welded blanks was evaluated in terms of limiting dome height (LDH), forming limit diagram, and deep drawn cup depth. The effect of the presence of WZ on the formability of the C-103 sheet was estimated under uniaxial, plane strain, and biaxial tensile strain paths for the first time, and the results were compared with the monolithic sample. It was noted that the failure limit of the welded specimens decreased compared to that of the monolithic sample, resulting in a lower LDH of approximately 69% and 62% when deformed along plane strain and biaxial tensile strain paths, respectively. However, a marginal variation in LDH was observed for the uniaxial strain path. Also, the welded blank had more resistance to material flow into the die cavity due to the harder weld region, resulting in a reduction of deep drawn cup depth by 52% than that of the monolithic blank. The overall results concluded that the presence of the WZ significantly affected the formability of the C-103 sheet, especially in plane strain and biaxial strain paths. However, the fracture was never found to be propagating along the weld line, indicating the ability of the weld to sustain large plastic strains. This study provides insightful information on the formability of electron beam welded C-103 sheets for the successful fabrication of space components.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106912"},"PeriodicalIF":4.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527915","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 : 2024-10-04DOI: 10.1016/j.ijrmhm.2024.106911
Funsho Olaitan Kolawole
{"title":"Corrigendum to “Tribological behavior of duplex CrN/DLC and nano-multilayer DLC-W coatings on valve tappet under elevated temperature and varying load” [International Journal of Refractory Metals and Hard Materials, 121 (2024) 106660","authors":"Funsho Olaitan Kolawole","doi":"10.1016/j.ijrmhm.2024.106911","DOIUrl":"10.1016/j.ijrmhm.2024.106911","url":null,"abstract":"","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106911"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527916","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 : 2024-10-02DOI: 10.1016/j.ijrmhm.2024.106910
Hao Jiang , Zhiwei Zhao , Panjun Wang , Xiaowei Liang , Qiujun Hu , Liuyang Bai , Hongjuan Zheng , Zheng Chen
The growing high-precision manufacturing industry is increasing the demand for cemented carbide which has fine grain size and excellent machinability. In this research, ultrafine cemented carbide was successfully prepared by the method of in-situ synthesis using spark plasma sintering as densification method, V, Cr, WC and carbon black as raw materials. The formation mechanism of in-situ preparation of grain growth inhibitors (GGIs) and its influence on the properties of alloys were investigated. An excellent mechanical property (HV 2254 kgf/mm2, KIC 9.20 MPa·m1/2) and uniform microstructure of the alloys (0.8 wt% V8C7–0.8 wt% Cr3C2) prepared under 1350 °C, 6 min, 25 MPa were demonstrated by the results. The WC grain growth was significantly inhibited (about 200 nm). The in-situ synthesized GGIs significantly inhibited grain coarsening by interfering with the dissolution-precipitation process of WC during liquid-phase sintering. The combination of SPS and in-situ synthesized GGIs offers a novel approach to exploration of the preparation of high-performance ultrafine or nanocrystalline cemented carbides.
{"title":"Preparation of ultrafine WC-V8C7-Cr3C2-co cemented carbides by spark plasma sintering in-situ synthesis of composite grain growth inhibitors","authors":"Hao Jiang , Zhiwei Zhao , Panjun Wang , Xiaowei Liang , Qiujun Hu , Liuyang Bai , Hongjuan Zheng , Zheng Chen","doi":"10.1016/j.ijrmhm.2024.106910","DOIUrl":"10.1016/j.ijrmhm.2024.106910","url":null,"abstract":"<div><div>The growing high-precision manufacturing industry is increasing the demand for cemented carbide which has fine grain size and excellent machinability. In this research, ultrafine cemented carbide was successfully prepared by the method of <em>in-situ</em> synthesis using spark plasma sintering as densification method, V, Cr, WC and carbon black as raw materials. The formation mechanism of <em>in-situ</em> preparation of grain growth inhibitors (GGIs) and its influence on the properties of alloys were investigated. An excellent mechanical property (<em>H</em><sub><em>V</em></sub> 2254 kgf/mm<sup>2</sup>, <em>K</em><sub><em>IC</em></sub> 9.20 MPa·m<sup>1/2</sup>) and uniform microstructure of the alloys (0.8 wt% V<sub>8</sub>C<sub>7</sub>–0.8 wt% Cr<sub>3</sub>C<sub>2</sub>) prepared under 1350 °C, 6 min, 25 MPa were demonstrated by the results. The WC grain growth was significantly inhibited (about 200 nm). The <em>in-situ</em> synthesized GGIs significantly inhibited grain coarsening by interfering with the dissolution-precipitation process of WC during liquid-phase sintering. The combination of SPS and <em>in-situ</em> synthesized GGIs offers a novel approach to exploration of the preparation of high-performance ultrafine or nanocrystalline cemented carbides.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106910"},"PeriodicalIF":4.2,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419674","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 : 2024-10-02DOI: 10.1016/j.ijrmhm.2024.106909
Wei Su , Wei Luo , MaoYuan Hu , Xiaofen Wang
Aiming to save the high-priced Co resource, Ni, Cu and Cr3C2 were simultaneously used to modify WC–10Co fine grained hardmetal, and the effects of sintering temperature on microstructure, mechanical properties were investigated. The combined introduction of Cu/Cr3C2 can significantly inhibit the growth of WC grains caused by Ni. When sintered at 1420 °C, the hardness, strength and fracture toughness of WC–0.5Cr3C2–(5.4Co3.6Ni1Cu) alloy reach to 1652 HV30, 3301 MPa and 12.01 MPa·m1/2, respectively, which are higher than those of WC–10Co alloy (1601 HV30, 3193 MPa and 11.75 MPa·m1/2). In term of corrosion resistance, Ni and Cr3C2 can eliminate the adverse effect caused by Cu, as evidenced by the decreased passivation current density (Ipp) and the increased charge-transfer resistance (Rct). In this regard, Ni/Cu/Cr3C2 composite additive would be an effective method to conduct the partial replacement of Co by other low-priced metals without sacrificing the mechanical properties and the corrosion resistance of WC–Co hardmetal.
为了节约昂贵的 Co 资源，同时使用 Ni、Cu 和 Cr3C2 对 WC-10Co 细晶粒硬质合金进行改性，并研究了烧结温度对微观结构和机械性能的影响。Cu/Cr3C2 的联合引入可显著抑制由 Ni 引起的 WC 晶粒长大。在 1420 °C 烧结时，WC-0.5Cr3C2-（5.4Co3.6Ni1Cu）合金的硬度、强度和断裂韧性分别达到 1652 HV30、3301 MPa 和 12.01 MPa-m1/2，高于 WC-10Co 合金（1601 HV30、3193 MPa 和 11.75 MPa-m1/2）。在耐腐蚀性方面，Ni 和 Cr3C2 可以消除 Cu 带来的不利影响，这体现在钝化电流密度（Ipp）的降低和电荷转移电阻（Rct）的增加上。因此，Ni/Cu/Cr3C2 复合添加剂是在不牺牲 WC-Co 硬金属的机械性能和耐腐蚀性能的前提下，用其他低价金属部分替代 Co 的有效方法。
{"title":"Influences of Ni/Cu/Cr3C2 composite additive on microstructure and properties of WC–10Co fine grained hardmetal","authors":"Wei Su , Wei Luo , MaoYuan Hu , Xiaofen Wang","doi":"10.1016/j.ijrmhm.2024.106909","DOIUrl":"10.1016/j.ijrmhm.2024.106909","url":null,"abstract":"<div><div>Aiming to save the high-priced Co resource, Ni, Cu and Cr<sub>3</sub>C<sub>2</sub> were simultaneously used to modify WC–10Co fine grained hardmetal, and the effects of sintering temperature on microstructure, mechanical properties were investigated. The combined introduction of Cu/Cr<sub>3</sub>C<sub>2</sub> can significantly inhibit the growth of WC grains caused by Ni. When sintered at 1420 °C, the hardness, strength and fracture toughness of WC–0.5Cr<sub>3</sub>C<sub>2</sub>–(5.4Co3.6Ni1Cu) alloy reach to 1652 HV30, 3301 MPa and 12.01 MPa·m<sup>1/2</sup>, respectively, which are higher than those of WC–10Co alloy (1601 HV30, 3193 MPa and 11.75 MPa·m<sup>1/2</sup>). In term of corrosion resistance, Ni and Cr<sub>3</sub>C<sub>2</sub> can eliminate the adverse effect caused by Cu, as evidenced by the decreased passivation current density (I<sub>pp</sub>) and the increased charge-transfer resistance (R<sub>ct</sub>). In this regard, Ni/Cu/Cr<sub>3</sub>C<sub>2</sub> composite additive would be an effective method to conduct the partial replacement of Co by other low-priced metals without sacrificing the mechanical properties and the corrosion resistance of WC–Co hardmetal.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106909"},"PeriodicalIF":4.2,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419817","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 : 2024-09-30DOI: 10.1016/j.ijrmhm.2024.106908
Xiaoxiao Zhang , Shaomin Zhang , Cheng Yang , Ze Sun , Jiawei Ding
The electrochemical corrosion performance of WC-Co hard alloy was studied under pressure/pressureless sintering and conditions with/without graphene oxide added. Three electrochemical testing methods were used to evaluate the corrosion behavior: open circuit potential, electrochemical impedance spectroscopy, and dynamic potential polarization. The corrosion resistance of the alloy was compared using three parameters of corrosion potential, corrosion current density, and total impedance. The corrosion mechanism was studied by observing the surface morphology of corroded alloy using scanning electron microscopy and analyzing the surface corrosion products using X-ray photoelectron spectroscopy. The results showed that pseudo-passivation phenomenon appeared in the potentiodynamic polarization curve of the hard alloy in the sodium hydroxide solution. The corrosion behavior was mainly controlled by anodic dissolution, with the dissolution of WC phase being greater than that of Co phase. The corrosion resistant properties of the pressure sintered cemented carbide are higher than that of the pressure-less sintered cemented carbide respectively in NaOH solution, mainly because pressure increases the grain size and decreases the grain boundaries of cemented carbide, which can be regarded as the dislocation wall between grains and normally attacked by the serious corrosion preferentially.
研究了 WC-Co 硬质合金在加压/无压烧结以及添加/不添加氧化石墨烯条件下的电化学腐蚀性能。采用了三种电化学测试方法来评估腐蚀行为：开路电位、电化学阻抗光谱和动态电位极化。使用腐蚀电位、腐蚀电流密度和总阻抗三个参数比较了合金的耐腐蚀性。通过扫描电子显微镜观察腐蚀合金的表面形貌，并利用 X 射线光电子能谱分析表面腐蚀产物，研究了腐蚀机理。结果表明，硬质合金在氢氧化钠溶液中的电位极化曲线出现了伪钝化现象。腐蚀行为主要受阳极溶解控制，WC 相的溶解度大于 Co 相。在 NaOH 溶液中，加压烧结硬质合金的耐腐蚀性能分别高于无压烧结硬质合金，这主要是因为加压使硬质合金的晶粒尺寸增大，晶界减小，晶界可视为晶粒间的位错壁，通常优先受到严重腐蚀的侵蚀。
{"title":"Corrosion resistance of pressure/pressureless sintered cemented carbides with/without graphene oxide in NaOH solution","authors":"Xiaoxiao Zhang , Shaomin Zhang , Cheng Yang , Ze Sun , Jiawei Ding","doi":"10.1016/j.ijrmhm.2024.106908","DOIUrl":"10.1016/j.ijrmhm.2024.106908","url":null,"abstract":"<div><div>The electrochemical corrosion performance of WC-Co hard alloy was studied under pressure/pressureless sintering and conditions with/without graphene oxide added. Three electrochemical testing methods were used to evaluate the corrosion behavior: open circuit potential, electrochemical impedance spectroscopy, and dynamic potential polarization. The corrosion resistance of the alloy was compared using three parameters of corrosion potential, corrosion current density, and total impedance. The corrosion mechanism was studied by observing the surface morphology of corroded alloy using scanning electron microscopy and analyzing the surface corrosion products using X-ray photoelectron spectroscopy. The results showed that pseudo-passivation phenomenon appeared in the potentiodynamic polarization curve of the hard alloy in the sodium hydroxide solution. The corrosion behavior was mainly controlled by anodic dissolution, with the dissolution of WC phase being greater than that of Co phase. The corrosion resistant properties of the pressure sintered cemented carbide are higher than that of the pressure-less sintered cemented carbide respectively in NaOH solution, mainly because pressure increases the grain size and decreases the grain boundaries of cemented carbide, which can be regarded as the dislocation wall between grains and normally attacked by the serious corrosion preferentially.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"125 ","pages":"Article 106908"},"PeriodicalIF":4.2,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419733","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号