Pub Date : 2024-11-20DOI: 10.1016/j.ijrmhm.2024.106971
Liyu Hao , Xuanpu Zhang , Shangkun Shen , Xing Liu , Mingyou Niu , Rong Yan , Xuesong Leng , Engang Fu
Grain refinement in hafnium (Hf), a typical refractory metal, encounters significant challenges due to its inherent high sintering temperature requirements and uneven sintered capillary force that lead to rapid grain coarsening and inhomogeneity. Herein, we present a novel approach of the pressureless two-step sintering to prepare near-fully dense nanocrystalline Hf with an average grain size of around 40 nm, which represents the smallest grain and highest density for nanocrystalline pure Hf to the date. Such achievements not only broaden the applicability of pressureless two-step sintering but also offer insights to produce large size of finer-grained refractory metals and their alloys.
{"title":"Near-fully dense nanocrystalline hafnium via pressureless two-step sintering","authors":"Liyu Hao , Xuanpu Zhang , Shangkun Shen , Xing Liu , Mingyou Niu , Rong Yan , Xuesong Leng , Engang Fu","doi":"10.1016/j.ijrmhm.2024.106971","DOIUrl":"10.1016/j.ijrmhm.2024.106971","url":null,"abstract":"<div><div>Grain refinement in hafnium (Hf), a typical refractory metal, encounters significant challenges due to its inherent high sintering temperature requirements and uneven sintered capillary force that lead to rapid grain coarsening and inhomogeneity. Herein, we present a novel approach of the pressureless two-step sintering to prepare near-fully dense nanocrystalline Hf with an average grain size of around 40 nm, which represents the smallest grain and highest density for nanocrystalline pure Hf to the date. Such achievements not only broaden the applicability of pressureless two-step sintering but also offer insights to produce large size of finer-grained refractory metals and their alloys.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"127 ","pages":"Article 106971"},"PeriodicalIF":4.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747440","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 : 2024-11-20DOI: 10.1016/j.ijrmhm.2024.106962
Tran Dinh Cuong , Anh D. Phan
W is a ubiquitous refractory metal with numerous potential applications, but its high-pressure melting behaviors remain controversial. Some physicists suggest that the problem may be addressed by including the contribution of vacancies. However, their ideas stay unverified due to the lack of information about crystallographic defects in harsh environments. Herein, the statistical moment method is enhanced to illuminate how vacancies form and impact the melting properties of W. Our anharmonic calculations indicate that the well-known Arrhenius law fails to model the proliferation of vacancies during isobaric heating. Besides, the Gibbs energy of vacancy formation will be severely underestimated if the contribution of external work is neglected during isothermal squeezing. After scrutinizing both temperature and pressure effects, we conclude that the equilibrium vacancy concentration of W drops dramatically along the solid-liquid boundary. Therefore, the Gorecki criterion cannot be applied to describe the melting phenomenon of W. We also demonstrate that the vacancy-mediated melting model of Errandonea is inappropriate for explaining the emergence of abnormally low melting signals in diamond-anvil-cell measurements. Instead, the carbon contamination of W samples should be thoroughly considered to resolve the discrepancy between experimental and computational results. Finally, we revisit the vacancy correction technique of Hung et al. and find that it only depresses the melting temperature by a few percent. The listed pieces of evidence show that the influences of vacancies can be safely ignored when investigating the melting process of W under extreme conditions.
{"title":"Novel insights into vacancy effects on high-pressure melting of W from anharmonic statistical moment method","authors":"Tran Dinh Cuong , Anh D. Phan","doi":"10.1016/j.ijrmhm.2024.106962","DOIUrl":"10.1016/j.ijrmhm.2024.106962","url":null,"abstract":"<div><div>W is a ubiquitous refractory metal with numerous potential applications, but its high-pressure melting behaviors remain controversial. Some physicists suggest that the problem may be addressed by including the contribution of vacancies. However, their ideas stay unverified due to the lack of information about crystallographic defects in harsh environments. Herein, the statistical moment method is enhanced to illuminate how vacancies form and impact the melting properties of W. Our anharmonic calculations indicate that the well-known Arrhenius law fails to model the proliferation of vacancies during isobaric heating. Besides, the Gibbs energy of vacancy formation will be severely underestimated if the contribution of external work is neglected during isothermal squeezing. After scrutinizing both temperature and pressure effects, we conclude that the equilibrium vacancy concentration of W drops dramatically along the solid-liquid boundary. Therefore, the Gorecki criterion cannot be applied to describe the melting phenomenon of W. We also demonstrate that the vacancy-mediated melting model of Errandonea is inappropriate for explaining the emergence of abnormally low melting signals in diamond-anvil-cell measurements. Instead, the carbon contamination of W samples should be thoroughly considered to resolve the discrepancy between experimental and computational results. Finally, we revisit the vacancy correction technique of Hung et al. and find that it only depresses the melting temperature by a few percent. The listed pieces of evidence show that the influences of vacancies can be safely ignored when investigating the melting process of W under extreme conditions.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"127 ","pages":"Article 106962"},"PeriodicalIF":4.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747436","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 : 2024-11-19DOI: 10.1016/j.ijrmhm.2024.106968
Ya-Feng Wang , Jiu-Xiong Chen , Lai-Ma Luo , Yong-Qiang Qin , Fei Sun , Di Dong , Yu-Cheng Wu
W10Re alloy is preferred for computed tomography anodes with high molar heat capacity. The deformed W10Re alloy will undergo recrystallization and grain growth during service, resulting in reduced mechanical properties, thermal shock resistance, and service life. The aim of this work is to study the microstructure of the warm-rolled W10Re alloy, its evolution of microstructure and mechanical properties after annealing at 1500 °C. During annealing at 1500 °C, recrystallization and growth of the deformed grain occurred with a latent period. The characteristics of deformed grains in the as-rolled alloy and the variation of kernel average misorientation (KAM) and geometrically necessary dislocations (GND) densities during recrystallization are discussed in detail. In high-temperature annealing, lower stored energy can allow the recrystallization behavior to have a latent period, and the residual deformation of the grain can be retained for a long time. In elevated temperatures, the deterioration of the mechanical properties of the alloy is initially evidenced by a notable decline in strength. This is subsequently followed by the loss of plasticity, which occurs as a result of the further degradation of the structure.
{"title":"Evolution of microstructure and mechanical properties of warm-rolled W10Re alloy during annealing at 1500 °C","authors":"Ya-Feng Wang , Jiu-Xiong Chen , Lai-Ma Luo , Yong-Qiang Qin , Fei Sun , Di Dong , Yu-Cheng Wu","doi":"10.1016/j.ijrmhm.2024.106968","DOIUrl":"10.1016/j.ijrmhm.2024.106968","url":null,"abstract":"<div><div>W<img>10Re alloy is preferred for computed tomography anodes with high molar heat capacity. The deformed W<img>10Re alloy will undergo recrystallization and grain growth during service, resulting in reduced mechanical properties, thermal shock resistance, and service life. The aim of this work is to study the microstructure of the warm-rolled W<img>10Re alloy, its evolution of microstructure and mechanical properties after annealing at 1500 °C. During annealing at 1500 °C, recrystallization and growth of the deformed grain occurred with a latent period. The characteristics of deformed grains in the as-rolled alloy and the variation of kernel average misorientation (KAM) and geometrically necessary dislocations (GND) densities during recrystallization are discussed in detail. In high-temperature annealing, lower stored energy can allow the recrystallization behavior to have a latent period, and the residual deformation of the grain can be retained for a long time. In elevated temperatures, the deterioration of the mechanical properties of the alloy is initially evidenced by a notable decline in strength. This is subsequently followed by the loss of plasticity, which occurs as a result of the further degradation of the structure.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"127 ","pages":"Article 106968"},"PeriodicalIF":4.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719668","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 : 2024-11-19DOI: 10.1016/j.ijrmhm.2024.106969
Simon Pillmeier , Stanislav Žák , Reinhard Pippan , Jürgen Eckert , Anton Hohenwarter
The fracture and fatigue crack growth behavior of two molybdenum alloys, containing 41 wt-% and 47.5 wt-% rhenium, respectively, are investigated. These alloys were provided in form of cold-wrought rods of 6 mm diameter and exhibit a refined microstructure with highly elongated grains and a strong fiber texture. Similarly processed pure molybdenum was used as reference material and exhibits a significantly coarser microstructure. SEN(T) and C(T) specimens were tested with R-L and L-R orientation. In both, quasi-static and fatigue crack growth experiments, L-R oriented cracks immediately kinked by 90° into the direction of grain elongation. This yields fracture toughness values and effective and long crack threshold values about twice as high as for R-L oriented cracks, which is in good agreement with calculations of a reduced local crack driving force. In both MoRe alloys a cyclic R-curve behavior was captured in fatigue crack growth tests at a load ratio of R = 0.1, while for MoRe47.5 it was still present at R = 0.7. This is attributed mainly to the coarser microstructure. The effective thresholds ∆Kth,eff of both MoRe alloys are remarkably low and deviate from a commonly used estimation, especially for the MoRe47.5 material. It is proposed that plasticity in these materials is facilitated by twinning, leading to the emission of partial dislocations from the crack tip. Although no clear microstructural or fractographic evidence was found, a recalculation of ∆Kth,eff considering partial dislocations indicates a good correlation with experimental values.
{"title":"Exploring the fracture toughness and fatigue crack growth behavior of MoRe alloys","authors":"Simon Pillmeier , Stanislav Žák , Reinhard Pippan , Jürgen Eckert , Anton Hohenwarter","doi":"10.1016/j.ijrmhm.2024.106969","DOIUrl":"10.1016/j.ijrmhm.2024.106969","url":null,"abstract":"<div><div>The fracture and fatigue crack growth behavior of two molybdenum alloys, containing 41 wt-% and 47.5 wt-% rhenium, respectively, are investigated. These alloys were provided in form of cold-wrought rods of 6 mm diameter and exhibit a refined microstructure with highly elongated grains and a strong fiber texture. Similarly processed pure molybdenum was used as reference material and exhibits a significantly coarser microstructure. SEN(T) and C(T) specimens were tested with R-L and L-R orientation. In both, quasi-static and fatigue crack growth experiments, L-R oriented cracks immediately kinked by 90° into the direction of grain elongation. This yields fracture toughness values and effective and long crack threshold values about twice as high as for R-L oriented cracks, which is in good agreement with calculations of a reduced local crack driving force. In both MoRe alloys a cyclic R-curve behavior was captured in fatigue crack growth tests at a load ratio of <em>R</em> = 0.1, while for MoRe47.5 it was still present at <em>R</em> = 0.7. This is attributed mainly to the coarser microstructure. The effective thresholds <em>∆K</em><sub><em>th,eff</em></sub> of both MoRe alloys are remarkably low and deviate from a commonly used estimation, especially for the MoRe47.5 material. It is proposed that plasticity in these materials is facilitated by twinning, leading to the emission of partial dislocations from the crack tip. Although no clear microstructural or fractographic evidence was found, a recalculation of <em>∆K</em><sub><em>th,eff</em></sub> considering partial dislocations indicates a good correlation with experimental values.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"127 ","pages":"Article 106969"},"PeriodicalIF":4.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700878","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 : 2024-11-17DOI: 10.1016/j.ijrmhm.2024.106957
Xiulan Li, Xiao Jiang, Xinjun Zhou, Xuan Li, Xudong Zhang
The oxidation experiments on WC-Cu-10Ni-5Mn-3Sn-1.5TiC and WC-Cu-10Ni-5Mn-3Sn-1.5TiC-0.6Ce2O3 materials were carried out for 2 h, 4 h, 6 h, 8 h, and 10 h in the temperature range of 500–800 °C, respectively, to elucidate the effects of oxidation temperatures and times on the properties of cemented carbides. The evolution laws of oxidation products and oxide layer microstructure of WC-Cu-10Ni-5Mn-3Sn-1.5TiC-0.6 Ce2O3 cemented carbide material with the change of temperature and time were mainly investigated. The oxidation behavior and oxidation mechanism were analyzed in combination with the oxidation kinetics and thermodynamics of the formation of oxidation products. The results revealed that the addition of Ce2O3 improved the oxidation resistance of the cemented carbide material at 500–800 °C after 2–10 h of heat treatment. With the increase of oxidation temperature or the prolongation of oxidation time at the same temperature, the oxidation resistance of the cemented carbide material decreased. The cemented carbides were shown to withstand a long-term oxidation at 500 °C. However, the surface of the material was completely oxidized even after 2 h of oxidation at the temperature of 800 °C. The products of the interaction between O2− and metal ions appeared in the following order: Cu2O, WO2, WO3 + Mn3O4 + MnO, CuO, W18O49, and Mn2O3 + MnO2. Moreover, the oxidation products of the same element changed from low to high valence. However, the high-valence oxidation was also reduced to a low-valence state in the complex oxidation process involving many elements. Meanwhile, the oxidation products with greater thermodynamic driving force were not detected in the oxide layer due to the influence of element diffusion, the ionization energy and the competition with O2 during the formation and growth of oxides.
{"title":"Effect of 1.5TiC/1.5TiC + 0.6 Ce2O3 addition on the oxidation behavior of WC-Cu-10Ni-5Mn-3Sn cemented carbides","authors":"Xiulan Li, Xiao Jiang, Xinjun Zhou, Xuan Li, Xudong Zhang","doi":"10.1016/j.ijrmhm.2024.106957","DOIUrl":"10.1016/j.ijrmhm.2024.106957","url":null,"abstract":"<div><div>The oxidation experiments on WC-Cu-10Ni-5Mn-3Sn-1.5TiC and WC-Cu-10Ni-5Mn-3Sn-1.5TiC-0.6Ce<sub>2</sub>O<sub>3</sub> materials were carried out for 2 h, 4 h, 6 h, 8 h, and 10 h in the temperature range of 500–800 °C, respectively, to elucidate the effects of oxidation temperatures and times on the properties of cemented carbides. The evolution laws of oxidation products and oxide layer microstructure of WC-Cu-10Ni-5Mn-3Sn-1.5TiC-0.6 Ce<sub>2</sub>O<sub>3</sub> cemented carbide material with the change of temperature and time were mainly investigated. The oxidation behavior and oxidation mechanism were analyzed in combination with the oxidation kinetics and thermodynamics of the formation of oxidation products. The results revealed that the addition of Ce<sub>2</sub>O<sub>3</sub> improved the oxidation resistance of the cemented carbide material at 500–800 °C after 2–10 h of heat treatment. With the increase of oxidation temperature or the prolongation of oxidation time at the same temperature, the oxidation resistance of the cemented carbide material decreased. The cemented carbides were shown to withstand a long-term oxidation at 500 °C. However, the surface of the material was completely oxidized even after 2 h of oxidation at the temperature of 800 °C. The products of the interaction between O<sup>2−</sup> and metal ions appeared in the following order: Cu<sub>2</sub>O, WO<sub>2</sub>, WO<sub>3</sub> + Mn<sub>3</sub>O<sub>4</sub> + MnO, CuO, W<sub>18</sub>O<sub>49</sub>, and Mn<sub>2</sub>O<sub>3</sub> + MnO<sub>2</sub>. Moreover, the oxidation products of the same element changed from low to high valence. However, the high-valence oxidation was also reduced to a low-valence state in the complex oxidation process involving many elements. Meanwhile, the oxidation products with greater thermodynamic driving force were not detected in the oxide layer due to the influence of element diffusion, the ionization energy and the competition with O<sub>2</sub> during the formation and growth of oxides.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106957"},"PeriodicalIF":4.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705096","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 : 2024-11-17DOI: 10.1016/j.ijrmhm.2024.106967
ZhaoPeng Hao, HuiHui Zhang, YiHang Fan
To better cutting the SiCp/Al composite material, it is necessary to accurately predict the tool wear state of the ultrasonic elliptic vibration cutting (UEVC) process. The main cutting force is one of the key output variables to evaluate the machining performance and the tool wear process. Therefore, based on the main cutting force, tool wear strength and tool wear mechanism, the relationship between the ratio of main cutting force and cutting yield strength and cutting wear are studied to find the optimal cutting temperature range of the minimum tool wear of SiCp/Al composite. Firstly, the tool wear experiments of UEVC SiCp/Al composite at different cutting speeds are conducted. Based on the analysis of the tool wear morphology, the tool wear mechanism is discussed, and the cutting temperature and the main cutting force value at different cutting speeds are measured. Then, the mathematical model of SiCp/Al composite is considering the characteristics of SiCp/Al composite. Finally, the optimal cutting temperature range is obtained based on this mathematical model. Furthermore, the accuracy of the mathematical model is verified by the tool wear experiment, and the best cutting temperature range is consistent with the prediction results.
{"title":"Tool wear mathematical model of PCD during ultrasonic elliptic vibration cutting SiCp/Al composite","authors":"ZhaoPeng Hao, HuiHui Zhang, YiHang Fan","doi":"10.1016/j.ijrmhm.2024.106967","DOIUrl":"10.1016/j.ijrmhm.2024.106967","url":null,"abstract":"<div><div>To better cutting the SiCp/Al composite material, it is necessary to accurately predict the tool wear state of the ultrasonic elliptic vibration cutting (UEVC) process. The main cutting force is one of the key output variables to evaluate the machining performance and the tool wear process. Therefore, based on the main cutting force, tool wear strength and tool wear mechanism, the relationship between the ratio of main cutting force and cutting yield strength and cutting wear are studied to find the optimal cutting temperature range of the minimum tool wear of SiCp/Al composite. Firstly, the tool wear experiments of UEVC SiCp/Al composite at different cutting speeds are conducted. Based on the analysis of the tool wear morphology, the tool wear mechanism is discussed, and the cutting temperature and the main cutting force value at different cutting speeds are measured. Then, the mathematical model of SiCp/Al composite is considering the characteristics of SiCp/Al composite. Finally, the optimal cutting temperature range is obtained based on this mathematical model. Furthermore, the accuracy of the mathematical model is verified by the tool wear experiment, and the best cutting temperature range is consistent with the prediction results.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106967"},"PeriodicalIF":4.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705098","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}
A novel chemical vapor deposition (CVD) multilayer coating intended for cutting applications was designed to achieve high wear and heat resistance during metal machining. The coating consists of three layers: a TiCN layer deposited on top of a TiAlN layer, which was grown on a layer of TiN that was deposited onto a cemented carbide substrate. The detailed microstructure of the coating was examined using a combination of electron microscope techniques. Two pyramidal surface morphologies and textures were observed, which could be related to the substrate roughness. Two growth modes were found: epitaxial growth of 〈211〉 oriented TiCN on <211> oriented TiAlN on <211> oriented TiN, leading to tilted TiCN pyramids at the coating surface; and epitaxial growth of 〈111〉 TiCN on <111> TiAlN on <111> TiN, leading to symmetrical TiCN pyramids at the coating surface.
一种用于切削应用的新型化学气相沉积（CVD）多层涂层旨在实现金属加工过程中的高耐磨性和耐热性。涂层由三层组成：TiCN 层沉积在 TiAlN 层之上，TiAlN 层生长在沉积在硬质合金基底上的 TiN 层上。涂层的详细微观结构通过电子显微镜技术进行了检测。观察到两种金字塔形的表面形态和纹理，这可能与基底粗糙度有关。发现了两种生长模式：211〉取向 TiCN 在 <211> 取向 TiAlN 在 <211> 取向 TiN 上的外延生长，导致涂层表面出现倾斜的 TiCN 金字塔；以及 〈111〉TiCN 在 <111> TiAlN 在 <111> TiN 上的外延生长，导致涂层表面出现对称的 TiCN 金字塔。
{"title":"Growth of a hard, novel CVD multilayer coating: Ti(C,N) on (Ti,Al)N on TiN","authors":"Mohamed Ben Hassine , Hans-Olof Andrén , Anand H.S. Iyer , Olof Bäcke , Dirk Stiens , Wiebke Janssen , Johannes Kümmel , Mats Halvarsson","doi":"10.1016/j.ijrmhm.2024.106966","DOIUrl":"10.1016/j.ijrmhm.2024.106966","url":null,"abstract":"<div><div>A novel chemical vapor deposition (CVD) multilayer coating intended for cutting applications was designed to achieve high wear and heat resistance during metal machining. The coating consists of three layers: a TiCN layer deposited on top of a TiAlN layer, which was grown on a layer of TiN that was deposited onto a cemented carbide substrate. The detailed microstructure of the coating was examined using a combination of electron microscope techniques. Two pyramidal surface morphologies and textures were observed, which could be related to the substrate roughness. Two growth modes were found: epitaxial growth of 〈211〉 oriented TiCN on <211> oriented TiAlN on <211> oriented TiN, leading to tilted TiCN pyramids at the coating surface; and epitaxial growth of 〈111〉 TiCN on <111> TiAlN on <111> TiN, leading to symmetrical TiCN pyramids at the coating surface.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"127 ","pages":"Article 106966"},"PeriodicalIF":4.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701000","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}
In this study, the deformation characteristics of as-forged pure tantalum were investigated using a Gleeble-3800 thermal simulation testing machine in the temperature range of room temperature to 350 °C and strain rates ranging from 0.1 to 10 s−1, with a maximum deformation of 60 %. Results show that the deformation resistance increases with decreasing deformation temperature and increasing strain rate before reaching the peak stress. After reaching peak stress, deformation is dominated by dynamic recovery mechanisms. Based on the true stress-strain curves obtained from experiments, the deformation activation energy (Q) and stress exponent (n) of the material were calculated to be 5.133 kJ/mol and 3.1989, respectively. A constitutive equation describing the rheological behavior was established. Utilizing processing maps combined with post-deformation microstructures, optimal processing parameters were determined to be a deformation temperature of room temperature, a strain rate ranging from 3.5 to 10 s−1, and a dissipation rate of 0.12. Under these optimal processing parameters, the material microstructure mainly consisted of dynamically recrystallized grains and deformed grains.
{"title":"The study of deformation behavior and microstructure evolution in forged pure tantalum","authors":"Zhong Jiahao , Jia Zhiqiang , Zhang Long , Zhu Yanchun , Wu Hao","doi":"10.1016/j.ijrmhm.2024.106965","DOIUrl":"10.1016/j.ijrmhm.2024.106965","url":null,"abstract":"<div><div>In this study, the deformation characteristics of as-forged pure tantalum were investigated using a Gleeble-3800 thermal simulation testing machine in the temperature range of room temperature to 350 °C and strain rates ranging from 0.1 to 10 s<sup>−1</sup>, with a maximum deformation of 60 %. Results show that the deformation resistance increases with decreasing deformation temperature and increasing strain rate before reaching the peak stress. After reaching peak stress, deformation is dominated by dynamic recovery mechanisms. Based on the true stress-strain curves obtained from experiments, the deformation activation energy (Q) and stress exponent (n) of the material were calculated to be 5.133 kJ/mol and 3.1989, respectively. A constitutive equation describing the rheological behavior was established. Utilizing processing maps combined with post-deformation microstructures, optimal processing parameters were determined to be a deformation temperature of room temperature, a strain rate ranging from 3.5 to 10 s<sup>−1</sup>, and a dissipation rate of 0.12. Under these optimal processing parameters, the material microstructure mainly consisted of dynamically recrystallized grains and deformed grains.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"127 ","pages":"Article 106965"},"PeriodicalIF":4.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700999","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 : 2024-11-15DOI: 10.1016/j.ijrmhm.2024.106964
Yong Niu , Pan Gong , Xiao Xu , Xin Wang , Yunfei Ma , Maojun Li , Qingzhong Lu , Hanmin Yang , Zhao Liu , Mao Zhang , Xuefeng Tang , Xinyun Wang
In this study, Spark Plasma Sintering (SPS) was utilized to fabricate fine-grained cemented carbides, and an orthogonal experimental design was employed to examine the influence of holding temperature (1100 °C, 1200 °C, 1300 °C) and holding time (5, 10, and 15 min) on the performance of WC-10Co cemented carbide specimens. Compared with conventional sintering methods, this work achieved the production of samples with enhanced overall performance at lower temperatures and shorter durations. Specifically, under the conditions of a holding temperature of 1300 °C and a holding time of 5 min, the resulting specimens exhibited a density of 14.64 g/cm3, a hardness of 91.29 HRA, a fracture toughness of 16.39 MPa·m½, and a transverse rupture strength of 2398 MPa. The microstructural analysis revealed that as the holding temperature increased, the Co phase in the specimens underwent a transformation from its initial powder form to banded cobalt and subsequently to slit-shaped cobalt. It was found that the presence of banded cobalt effectively hinders crack propagation, whereas slit-shaped cobalt is more effective in preventing crack initiation, thus impacting the overall performance of the specimens. By analyzing the sintering curves and microstructures, the densification mechanisms during SPS sintering of WC-Co cemented carbides were elucidated. The study concluded that the state changes of the Co phase play a significant role in the densification behavior, final microstructure, and properties of the sintered material. These findings offer valuable insights for understanding and optimizing the SPS process.
{"title":"Preparation of WC-Co cemented carbide by spark plasma sintering: Microstructure evolution, mechanical properties and densification mechanism","authors":"Yong Niu , Pan Gong , Xiao Xu , Xin Wang , Yunfei Ma , Maojun Li , Qingzhong Lu , Hanmin Yang , Zhao Liu , Mao Zhang , Xuefeng Tang , Xinyun Wang","doi":"10.1016/j.ijrmhm.2024.106964","DOIUrl":"10.1016/j.ijrmhm.2024.106964","url":null,"abstract":"<div><div>In this study, Spark Plasma Sintering (SPS) was utilized to fabricate fine-grained cemented carbides, and an orthogonal experimental design was employed to examine the influence of holding temperature (1100 °C, 1200 °C, 1300 °C) and holding time (5, 10, and 15 min) on the performance of WC-10Co cemented carbide specimens. Compared with conventional sintering methods, this work achieved the production of samples with enhanced overall performance at lower temperatures and shorter durations. Specifically, under the conditions of a holding temperature of 1300 °C and a holding time of 5 min, the resulting specimens exhibited a density of 14.64 g/cm<sup>3</sup>, a hardness of 91.29 HRA, a fracture toughness of 16.39 MPa·m½, and a transverse rupture strength of 2398 MPa. The microstructural analysis revealed that as the holding temperature increased, the Co phase in the specimens underwent a transformation from its initial powder form to banded cobalt and subsequently to slit-shaped cobalt. It was found that the presence of banded cobalt effectively hinders crack propagation, whereas slit-shaped cobalt is more effective in preventing crack initiation, thus impacting the overall performance of the specimens. By analyzing the sintering curves and microstructures, the densification mechanisms during SPS sintering of WC-Co cemented carbides were elucidated. The study concluded that the state changes of the Co phase play a significant role in the densification behavior, final microstructure, and properties of the sintered material. These findings offer valuable insights for understanding and optimizing the SPS process.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106964"},"PeriodicalIF":4.2,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705095","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 : 2024-11-15DOI: 10.1016/j.ijrmhm.2024.106952
Miaoxia Xie , Long Zhang , Xintao Ren , Chengyu Xiang , Linjie Zhang , Won-Ik Cho
Effects of adding nano-sized ZrC in the fusion zone (FZ) on the microstructures and properties of laser-welded joints of pure molybdenum (Mo) and underlying mechanisms were explored. Compared with the joints without ZrC, the average microhardness of the FZ increases from 180 HV to 330 HV, the tensile strength of joints grows from 32 MPa to 386 MPa, and the fracture mode of joints switches from intergranular fractures to that dominated by cleavage fractures, after adding ZrC. ZrC, ZrO2, and Mo2C are detected in the FZ after adding ZrC. ZrC and ZrO2 is mainly found on grain boundaries (GBs). ZrC is able to deplete O in the FZ, thus decreasing the amount of harmful molybdenum (Mo) oxides on GBs, so it plays a role in purifying and strengthening GBs. ZrC, ZrO2, and Mo2C particles not only hinder dislocation movement and GB movement, but also serve as effective heterogeneous nucleation cores and therefore can refine grains in the FZ. The average grain size in the FZ of the joint without ZrC is 47.6 μm, while it is 28.4 μm after adding ZrC, which reduces by 40.3 % compared with the former. The significant improvement of the joint strength after adding ZrC is a result of joint action of dispersion strengthening, fine-grain strengthening, and GB purification.
{"title":"Microstructural and mechanical properties of laser-welded molybdenum joints with the addition of nano-sized ZrC in the weld pool","authors":"Miaoxia Xie , Long Zhang , Xintao Ren , Chengyu Xiang , Linjie Zhang , Won-Ik Cho","doi":"10.1016/j.ijrmhm.2024.106952","DOIUrl":"10.1016/j.ijrmhm.2024.106952","url":null,"abstract":"<div><div>Effects of adding nano-sized ZrC in the fusion zone (FZ) on the microstructures and properties of laser-welded joints of pure molybdenum (Mo) and underlying mechanisms were explored. Compared with the joints without ZrC, the average microhardness of the FZ increases from 180 HV to 330 HV, the tensile strength of joints grows from 32 MPa to 386 MPa, and the fracture mode of joints switches from intergranular fractures to that dominated by cleavage fractures, after adding ZrC. ZrC, ZrO<sub>2</sub>, and Mo<sub>2</sub>C are detected in the FZ after adding ZrC. ZrC and ZrO<sub>2</sub> is mainly found on grain boundaries (GBs). ZrC is able to deplete O in the FZ, thus decreasing the amount of harmful molybdenum (Mo) oxides on GBs, so it plays a role in purifying and strengthening GBs. ZrC, ZrO<sub>2</sub>, and Mo<sub>2</sub>C particles not only hinder dislocation movement and GB movement, but also serve as effective heterogeneous nucleation cores and therefore can refine grains in the FZ. The average grain size in the FZ of the joint without ZrC is 47.6 μm, while it is 28.4 μm after adding ZrC, which reduces by 40.3 % compared with the former. The significant improvement of the joint strength after adding ZrC is a result of joint action of dispersion strengthening, fine-grain strengthening, and GB purification.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106952"},"PeriodicalIF":4.2,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705097","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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