Pub Date : 2024-11-14DOI: 10.1016/j.ijrmhm.2024.106961
Houzhen Chen , Fuming Deng , Hui Xie , Xiaozhou Chen , Xiaotian Xing , Ziyi Liu , Wenli Deng , Junzhe Yu , Can Li
To investigate the effect of binder type on the interface and properties of PcBN composite, a series of PcBN composites with Al, TiN, Co, Ni, and W as binders were prepared under the conditions of 5.5–6 GPa, 1450–1550 °C, and 50 min, the interfacial bonding mechanism and material properties of PcBN composite were analyzed and discussed using SEM/EDS, XRD, and mechanical testing equipment. The results show that new phases are generated in the sintering of PcBN composites with different types of binders, which are uniformly distributed at the grain boundaries or in the interstices of grains to form a dense organization; cBN-cBN and cBN-TiN grain boundaries are formed in metal and ceramic binder PcBN, respectively, and the microhardness reaches 41.66 GPa at the highest level. In addition, the metal binder mainly diffuses by capillary force, while the ceramic binder mainly infiltrates with each other. This shows that the mutual infiltration of the phases within the PcBN material layer and the cemented carbide layer is the key factor in improving the interfacial bond strength.
{"title":"Interfacial structure and performance analysis of PcBN composites with metal/ceramic binder","authors":"Houzhen Chen , Fuming Deng , Hui Xie , Xiaozhou Chen , Xiaotian Xing , Ziyi Liu , Wenli Deng , Junzhe Yu , Can Li","doi":"10.1016/j.ijrmhm.2024.106961","DOIUrl":"10.1016/j.ijrmhm.2024.106961","url":null,"abstract":"<div><div>To investigate the effect of binder type on the interface and properties of PcBN composite, a series of PcBN composites with Al, TiN, Co, Ni, and W as binders were prepared under the conditions of 5.5–6 GPa, 1450–1550 °C, and 50 min, the interfacial bonding mechanism and material properties of PcBN composite were analyzed and discussed using SEM/EDS, XRD, and mechanical testing equipment. The results show that new phases are generated in the sintering of PcBN composites with different types of binders, which are uniformly distributed at the grain boundaries or in the interstices of grains to form a dense organization; cBN-cBN and cBN-TiN grain boundaries are formed in metal and ceramic binder PcBN, respectively, and the microhardness reaches 41.66 GPa at the highest level. In addition, the metal binder mainly diffuses by capillary force, while the ceramic binder mainly infiltrates with each other. This shows that the mutual infiltration of the phases within the PcBN material layer and the cemented carbide layer is the key factor in improving the interfacial bond strength.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106961"},"PeriodicalIF":4.2,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The specific strength of refractory high entropy alloys (RHEAs) is usually impaired due to the high density of constituent elements. In order to develop a low-density RHEA, the microstructure and mechanical property of MoNbVTa0.5-based RHEAs with various Al additions have been investigated in this study. All samples exhibited a monolithic BCC solid solution structure. The addition of Al resulted in improved yield strength but a degraded plasticity at ambient temperature. In contrast, the yield strength consistently decreased with increasing Al content at elevated temperatures, and the softening occurred at ∼1000 °C. MoNbVTa0.5Al0.3 exhibited high specific strengths of 119.2 MPa cm3/g, 108.6 MPa cm3/g and 97.3 MPa cm3/g at 600 °C, 800 °C, and 1000 °C, respectively.
{"title":"Microstructure and mechanical properties of MoNbVTa0.5Alx refractory high entropy alloys","authors":"Wei Guo , Mengyuan Zhu , Sheng Yu , Weijie Zheng , Mi Zhao , Shulin Lü , Shusen Wu","doi":"10.1016/j.ijrmhm.2024.106960","DOIUrl":"10.1016/j.ijrmhm.2024.106960","url":null,"abstract":"<div><div>The specific strength of refractory high entropy alloys (RHEAs) is usually impaired due to the high density of constituent elements. In order to develop a low-density RHEA, the microstructure and mechanical property of MoNbVTa<sub>0.5</sub>-based RHEAs with various Al additions have been investigated in this study. All samples exhibited a monolithic BCC solid solution structure. The addition of Al resulted in improved yield strength but a degraded plasticity at ambient temperature. In contrast, the yield strength consistently decreased with increasing Al content at elevated temperatures, and the softening occurred at ∼1000 °C. MoNbVTa<sub>0.5</sub>Al<sub>0.3</sub> exhibited high specific strengths of 119.2 MPa cm<sup>3</sup>/g, 108.6 MPa cm<sup>3</sup>/g and 97.3 MPa cm<sup>3</sup>/g at 600 °C, 800 °C, and 1000 °C, respectively.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106960"},"PeriodicalIF":4.2,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656072","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 : 2024-11-10DOI: 10.1016/j.ijrmhm.2024.106958
Meiling Liu , Yajing Cao , Jiaying Feng , Wanxiu Hai , Yuhong Chen , Chengshang Zhou
The Ti(C,N)-based cermet were prepared by pressureless vacuum sintering using (Ti,W0.15,NbX)C pre-solid solution powder, and the effect of Nb molar ratio on microstructure, core/rim interface, mechanical and tribological properties were investigated. The results showed that increasing of Nb content led to distinct microstructural changes in the cermets. The gray core/Gy rim and white core/Gy rim microstructure enhanced mechanical properties, while the rimless black grains and gray core/black rim had a weakening effect. The cermet with (Ti,W0.15,Nb0.01)C had a Vickers hardness of 1664 MPa, fracture toughness of 10.3 MPa·m1/2 and transverse rupture strength of 1204 MPa. The average friction coefficient and the volume wear ratio at room temperature were 0.46 and 2.49E-8 mm3*N−1*m−1, respectively, with adhesive wear as the primary mechanism. At 600 °C, the average friction coefficient and the volume wear ratio were 0.37 and 1.15E-6 mm3*N−1*m−1, respectively, with tribo-oxidation being the dominant wear mechanism.
{"title":"Effect of Nb on microstructure and tribological properties of Ti(C, N)-based cermet","authors":"Meiling Liu , Yajing Cao , Jiaying Feng , Wanxiu Hai , Yuhong Chen , Chengshang Zhou","doi":"10.1016/j.ijrmhm.2024.106958","DOIUrl":"10.1016/j.ijrmhm.2024.106958","url":null,"abstract":"<div><div>The Ti(C,N)-based cermet were prepared by pressureless vacuum sintering using (Ti,W<sub>0.15</sub>,Nb<sub>X</sub>)C pre-solid solution powder, and the effect of Nb molar ratio on microstructure, core/rim interface, mechanical and tribological properties were investigated. The results showed that increasing of Nb content led to distinct microstructural changes in the cermets. The gray core/Gy rim and white core/Gy rim microstructure enhanced mechanical properties, while the rimless black grains and gray core/black rim had a weakening effect. The cermet with (Ti,W<sub>0.15</sub>,Nb<sub>0.01</sub>)C had a Vickers hardness of 1664 MPa, fracture toughness of 10.3 MPa·m<sup>1/2</sup> and transverse rupture strength of 1204 MPa. The average friction coefficient and the volume wear ratio at room temperature were 0.46 and 2.49E-8 mm<sup>3</sup>*N<sup>−1</sup>*m<sup>−1</sup>, respectively, with adhesive wear as the primary mechanism. At 600 °C, the average friction coefficient and the volume wear ratio were 0.37 and 1.15E-6 mm<sup>3</sup>*N<sup>−1</sup>*m<sup>−1</sup>, respectively, with tribo-oxidation being the dominant wear mechanism.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106958"},"PeriodicalIF":4.2,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655971","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 : 2024-11-09DOI: 10.1016/j.ijrmhm.2024.106956
Yuxin Zhong , Shixin Gao , Moyijie Huang , Yuntai Luo , Sha Zhao , Ping Chen , Chunyu Yin , Liang He , Jijun Yang , Kun Zhang
The study examined the diffusion mitigation effect and mechanical properties of the Nb interlayer prepared by magnetron sputtering as a CrZr diffusion barrier through annealing experiment, high-temperature air oxidation experiment and ring compression tests. The results show that the presence of an Nb interlayer significantly alleviates the CrZr interdiffusion, especially prevents the CrZr interdiffusion in the 1200 °C air environment and stabilizes the interface structure in the 1400 °C air environment. After undergoing air oxidation at 1200 °C, the Cr/Nb-coated samples showed the structure of Cr2O3, Cr, Cr2Nb Laves phase, Nb, (Zr, Nb) miscibility gap, β-Zr, α-Zr(O), and ZrO2 layers. During a certain period of argon annealing at 1332 °C, the increase in the thickness of the interlayer of the Cr/Nb coating, especially for samples containing micron sized Nb layer, is smaller than that of Cr-coated samples, indicating that the presence of the Nb layer is effective in alleviating the CrZr contact reaction to a certain extent. During the ring compression tests, the Cr/Nb coating is still firmly bonded to the Zr alloy cladding tube even under large deformation, and the micron-scale Nb layer releases part of the stress, resulting in short crack clusters on the surface of the coating instead of a large number of through-wall cracks. In summary, the Nb layer has the potential to be used as a diffusion barrier for CrZr interface, and the details of Nb as a diffusion barrier are discussed.
研究通过退火实验、高温空气氧化实验和环压试验，考察了磁控溅射制备的铌中间膜作为铬锆扩散屏障的扩散减缓效应和力学性能。结果表明，铌中间膜的存在明显减轻了铬锆的相互扩散，尤其是在 1200 °C 空气环境中阻止了铬锆的相互扩散，并在 1400 °C 空气环境中稳定了界面结构。经过 1200 ℃ 空气氧化后，Cr/Nb 涂层样品呈现出 Cr2O3、Cr、Cr2Nb Laves 相、Nb、（Zr，Nb）混溶间隙、β-Zr、α-Zr(O) 和 ZrO2 层结构。在 1332 °C氩气退火的一段时间内，Cr/Nb 涂层层间厚度的增加，尤其是含有微米级 Nb 层的样品，小于 Cr 涂层样品，这表明 Nb 层的存在在一定程度上有效缓解了 CrZr 接触反应。在环压试验中，即使在大变形的情况下，Cr/Nb 涂层仍与 Zr 合金包覆管牢固结合，微米级的 Nb 层释放了部分应力，导致涂层表面出现短裂纹簇，而不是大量的穿壁裂纹。总之，铌层有可能用作 CrZr 接口的扩散屏障，并对铌作为扩散屏障的细节进行了讨论。
{"title":"Study on Nb interlayer as CrZr diffusion barrier layer at high-temperature","authors":"Yuxin Zhong , Shixin Gao , Moyijie Huang , Yuntai Luo , Sha Zhao , Ping Chen , Chunyu Yin , Liang He , Jijun Yang , Kun Zhang","doi":"10.1016/j.ijrmhm.2024.106956","DOIUrl":"10.1016/j.ijrmhm.2024.106956","url":null,"abstract":"<div><div>The study examined the diffusion mitigation effect and mechanical properties of the Nb interlayer prepared by magnetron sputtering as a Cr<img>Zr diffusion barrier through annealing experiment, high-temperature air oxidation experiment and ring compression tests. The results show that the presence of an Nb interlayer significantly alleviates the Cr<img>Zr interdiffusion, especially prevents the Cr<img>Zr interdiffusion in the 1200 °C air environment and stabilizes the interface structure in the 1400 °C air environment. After undergoing air oxidation at 1200 °C, the Cr/Nb-coated samples showed the structure of Cr<sub>2</sub>O<sub>3</sub>, Cr, Cr<sub>2</sub>Nb Laves phase, Nb, (Zr, Nb) miscibility gap, β-Zr, α-Zr(O), and ZrO<sub>2</sub> layers. During a certain period of argon annealing at 1332 °C, the increase in the thickness of the interlayer of the Cr/Nb coating, especially for samples containing micron sized Nb layer, is smaller than that of Cr-coated samples, indicating that the presence of the Nb layer is effective in alleviating the Cr<img>Zr contact reaction to a certain extent. During the ring compression tests, the Cr/Nb coating is still firmly bonded to the Zr alloy cladding tube even under large deformation, and the micron-scale Nb layer releases part of the stress, resulting in short crack clusters on the surface of the coating instead of a large number of through-wall cracks. In summary, the Nb layer has the potential to be used as a diffusion barrier for Cr<img>Zr interface, and the details of Nb as a diffusion barrier are discussed.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106956"},"PeriodicalIF":4.2,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656068","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 : 2024-11-07DOI: 10.1016/j.ijrmhm.2024.106951
Li Zhang , Chunlin Zhang , Shengli Li , Shihan Zhang , Xingang Ai , Zhiwen Xie
Spherical WC particles are widely employed as hard phases to reinforce metal matrix coatings; however, their deposition during the surfacing process presents a significant challenge, resulting in limited improvements in coating hardness and wear resistance. In this work, these spherical WC as well as spherical/non-spherical WC particles have been used to prepare the WC reinforced nickel-based alloy coatings. The microstructure, mechanical, wear and fracture behavior of these coatings were investigated by detailed characterization. Results showed that spherical WC exhibited rapid sedimentation, and the primary decomposition products existed lump-like W2C. The ultimate decomposition process was based on the exfoliation of the diffusion layer. The spherical WC/Ni coatings exhibited a hardness of 13 GPa and an elastic modulus of 253 GPa, respectively. Notably, the wear rate of these coatings was relatively high, measuring 7.038 × 10−6 mm3/(N·m), while the stress and strain were comparatively low, standing at only 272.5 MPa and 0.72 %. In contrast, spherical/non-spherical WC/Ni coatings demonstrated distinct differential sedimentation behavior. Spherical WC particles settled at the bottom of the coating, whereas non-spherical WC particles were dispersed in the middle and upper regions. The decomposition of non-spherical WC particles was governed by the dissolution and diffusion of W2C, forming a skeleton-braided structure of M7C3, γ, and M23C6 phases on the coating surface. This unique structure increased the hardness of the coating to 21 GPa and the elastic modulus to 369 GPa, while reducing the wear rate to 2.853 × 10−6 mm3 (N · m) −1. In addition, the stress and strain reached 497.10 MPa and 1.97 % respectively, shifting the fracture mode to quasi-cleavage fracture with tear ridges. Overall, the spherical/non-spherical WC/Ni coating exhibited improved deformation resistance and superior wear resistance.
{"title":"Enhanced wear resistance and fracture resistance of spherical WC reinforced nickel-based alloy coating by adding non-spherical WC","authors":"Li Zhang , Chunlin Zhang , Shengli Li , Shihan Zhang , Xingang Ai , Zhiwen Xie","doi":"10.1016/j.ijrmhm.2024.106951","DOIUrl":"10.1016/j.ijrmhm.2024.106951","url":null,"abstract":"<div><div>Spherical WC particles are widely employed as hard phases to reinforce metal matrix coatings; however, their deposition during the surfacing process presents a significant challenge, resulting in limited improvements in coating hardness and wear resistance. In this work, these spherical WC as well as spherical/non-spherical WC particles have been used to prepare the WC reinforced nickel-based alloy coatings. The microstructure, mechanical, wear and fracture behavior of these coatings were investigated by detailed characterization. Results showed that spherical WC exhibited rapid sedimentation, and the primary decomposition products existed lump-like W<sub>2</sub>C. The ultimate decomposition process was based on the exfoliation of the diffusion layer. The spherical WC/Ni coatings exhibited a hardness of 13 GPa and an elastic modulus of 253 GPa, respectively. Notably, the wear rate of these coatings was relatively high, measuring 7.038 × 10<sup>−6</sup> mm<sup>3</sup>/(N·m), while the stress and strain were comparatively low, standing at only 272.5 MPa and 0.72 %. In contrast, spherical/non-spherical WC/Ni coatings demonstrated distinct differential sedimentation behavior. Spherical WC particles settled at the bottom of the coating, whereas non-spherical WC particles were dispersed in the middle and upper regions. The decomposition of non-spherical WC particles was governed by the dissolution and diffusion of W<sub>2</sub>C, forming a skeleton-braided structure of M<sub>7</sub>C<sub>3</sub>, γ, and M<sub>23</sub>C<sub>6</sub> phases on the coating surface. This unique structure increased the hardness of the coating to 21 GPa and the elastic modulus to 369 GPa, while reducing the wear rate to 2.853 × 10<sup>−6</sup> mm<sup>3</sup> (N · m) <sup>−1</sup>. In addition, the stress and strain reached 497.10 MPa and 1.97 % respectively, shifting the fracture mode to quasi-cleavage fracture with tear ridges. Overall, the spherical/non-spherical WC/Ni coating exhibited improved deformation resistance and superior wear resistance.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106951"},"PeriodicalIF":4.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656066","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 : 2024-11-07DOI: 10.1016/j.ijrmhm.2024.106954
Max Emmanuel , Zhuoqi Lucas Li , Harry Heptinstall , Oriol Gavalda-Diaz , Rachid M'saoubi , Tomas Persson , Susanne Norgren , Thomas Benjamin Britton , Finn Giuliani , Katharina Marquardt
The life of cutting tool inserts is critically important for efficient machining, reducing manufacturing cost, embedded energy, and enabling more complex parts to be machined. For these applications, cemented carbide (WC-Co) materials are a prime candidate. The performance of these materials can be limited by early fracture, typically via an intergranular fracture path with respect to carbide grains. This motivates further studies to understand the character of the grain boundary network so that grain boundary engineering (GBE) of WC-Co tools can be used to improve tool life and performance. In this work, we have used Rohrer et al.'s five-parameter grain boundary character distribution (GBCD) analysis to examine the grain boundary network of WC-10wt%Co and WC-10wt%Co-1wt%Cr samples (Rohrer et al., 2004a [1]). It was found that the measured area fraction of the Σ2 boundaries was comparable to the values reported in the literature despite the relatively larger grain sizes (∼14 μm) and higher cobalt contents. The result suggests that chromium doping increases the area fraction of Σ2 boundaries from 12.8 % to 14.8 %. It is proposed that this is a consequence of altering the Σ2 boundary energy, as associated with adding chromium.
{"title":"Effect of chromium doping on the grain boundary character of WC-Co","authors":"Max Emmanuel , Zhuoqi Lucas Li , Harry Heptinstall , Oriol Gavalda-Diaz , Rachid M'saoubi , Tomas Persson , Susanne Norgren , Thomas Benjamin Britton , Finn Giuliani , Katharina Marquardt","doi":"10.1016/j.ijrmhm.2024.106954","DOIUrl":"10.1016/j.ijrmhm.2024.106954","url":null,"abstract":"<div><div>The life of cutting tool inserts is critically important for efficient machining, reducing manufacturing cost, embedded energy, and enabling more complex parts to be machined. For these applications, cemented carbide (WC-Co) materials are a prime candidate. The performance of these materials can be limited by early fracture, typically via an intergranular fracture path with respect to carbide grains. This motivates further studies to understand the character of the grain boundary network so that grain boundary engineering (GBE) of WC-Co tools can be used to improve tool life and performance. In this work, we have used Rohrer et al.'s five-parameter grain boundary character distribution (GBCD) analysis to examine the grain boundary network of WC-10wt%Co and WC-10wt%Co-1wt%Cr samples (Rohrer et al., 2004a [<span><span>1</span></span>]). It was found that the measured area fraction of the Σ2 boundaries was comparable to the values reported in the literature despite the relatively larger grain sizes (∼14 μm) and higher cobalt contents. The result suggests that chromium doping increases the area fraction of Σ2 boundaries from 12.8 % to 14.8 %. It is proposed that this is a consequence of altering the Σ2 boundary energy, as associated with adding chromium.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106954"},"PeriodicalIF":4.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656069","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 : 2024-11-07DOI: 10.1016/j.ijrmhm.2024.106955
Mohamed Ragab Diab , Koki Murasawa , Ahmed Mohamed Mahmoud Ibrahim , Hiroshi Naragino , Tsuyoshi Yoshitake , Mohamed Egiza
Conventional machining lubricants pose environmental hazards and increase production costs. This study addresses this challenge by investigating nanodiamond composite (NDC) coatings deposited on WC–Co substrates as a lubricant-free alternative for sustainable machining. The NDC films show superior hardness (65 GPa) compared to the substrate (22 GPa) and enhanced adhesion (HF2). The NDC's unique self-lubrication results in a low and stable friction coefficient (COF ≤ 0.095) and exceptional wear resistance (7.45 × 10−8 mm3/N·m) in dry tesing against Al2O3 counter-body. Compared to CVD diamond, NDC coatings show a 47.8 % reduction in COF and a 31.65 % enhancement in wear resistance, promoting environmentally friendly machining practices.
{"title":"Wear-resistant and stable low-friction nanodiamond composite superhard coatings against Al2O3 counter-body in dry condition","authors":"Mohamed Ragab Diab , Koki Murasawa , Ahmed Mohamed Mahmoud Ibrahim , Hiroshi Naragino , Tsuyoshi Yoshitake , Mohamed Egiza","doi":"10.1016/j.ijrmhm.2024.106955","DOIUrl":"10.1016/j.ijrmhm.2024.106955","url":null,"abstract":"<div><div>Conventional machining lubricants pose environmental hazards and increase production costs. This study addresses this challenge by investigating nanodiamond composite (NDC) coatings deposited on WC–Co substrates as a lubricant-free alternative for sustainable machining. The NDC films show superior hardness (65 GPa) compared to the substrate (22 GPa) and enhanced adhesion (HF2). The NDC's unique self-lubrication results in a low and stable friction coefficient (COF ≤ 0.095) and exceptional wear resistance (7.45 × 10<sup>−8</sup> mm<sup>3</sup>/N·m) in dry tesing against Al<sub>2</sub>O<sub>3</sub> counter-body. Compared to CVD diamond, NDC coatings show a 47.8 % reduction in COF and a 31.65 % enhancement in wear resistance, promoting environmentally friendly machining practices.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106955"},"PeriodicalIF":4.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656070","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 : 2024-11-07DOI: 10.1016/j.ijrmhm.2024.106943
Youwei Liu , Yuxin Gao , Xiang Lei , Shuyuan Lin , Xiaoshan Zhu , Jinliang Wang
Pyrometallurgical recovery of rare-earth elements from NdFeB wastes is affected by the quality of the raw materials, and mixed rare-earth products add little value. Therefore, this study investigates NaBF4 fluoride roasting for the recovery of rare-earth elements and its underlying mechanisms. Reasonable roasting temperatures were determined based on thermodynamic calculations, and single-factor experiments were conducted. When roasted at 600 °C for 30 min with 65 % NaBF4, the fluorination rate of rare-earth elements reached 95.83 %. The composition of the clinker mesophase after roasting under different conditions was analyzed. At high temperatures, oxygen heteroatoms entered the crystal lattice of the rare-earth fluorides, which were subsequently removed during acid leaching, thereby reducing the recovery rate. A three-factor, three-level Box–Behnken test was conducted using the response surface methodology to analyze the effects of various factors and their interactions on the fluorination rate. Thus, an experimental basis for the recovery of rare-earth elements from NdFeB by fluoridation roasting was established. The roasting temperature had the greatest effect on the fluorination rate, followed by the roasting time and amount of NaBF4. The model predicted an optimal fluorination rate of 98.63 % when the material was roasted at 573 °C for 25 min with 59 % NaBF4. The clinker was acid-leached under optimal conditions (2.5 h at 80 °C with 9 M HCl and a liquid–solid ratio of 4 mL/g), and the Purity of fluorinated rare earths reached 99.39%. These results provide theoretical and experimental support for the application of pyrometallurgy in the recovery of rare-earth elements from NdFeB wastes.
{"title":"Mechanism and experimental study on the recovery of rare earth elements from neodymium iron boron waste by NaBF4 fluorination method","authors":"Youwei Liu , Yuxin Gao , Xiang Lei , Shuyuan Lin , Xiaoshan Zhu , Jinliang Wang","doi":"10.1016/j.ijrmhm.2024.106943","DOIUrl":"10.1016/j.ijrmhm.2024.106943","url":null,"abstract":"<div><div>Pyrometallurgical recovery of rare-earth elements from NdFeB wastes is affected by the quality of the raw materials, and mixed rare-earth products add little value. Therefore, this study investigates NaBF<sub>4</sub> fluoride roasting for the recovery of rare-earth elements and its underlying mechanisms. Reasonable roasting temperatures were determined based on thermodynamic calculations, and single-factor experiments were conducted. When roasted at 600 °C for 30 min with 65 % NaBF<sub>4</sub>, the fluorination rate of rare-earth elements reached 95.83 %. The composition of the clinker mesophase after roasting under different conditions was analyzed. At high temperatures, oxygen heteroatoms entered the crystal lattice of the rare-earth fluorides, which were subsequently removed during acid leaching, thereby reducing the recovery rate. A three-factor, three-level Box–Behnken test was conducted using the response surface methodology to analyze the effects of various factors and their interactions on the fluorination rate. Thus, an experimental basis for the recovery of rare-earth elements from NdFeB by fluoridation roasting was established. The roasting temperature had the greatest effect on the fluorination rate, followed by the roasting time and amount of NaBF<sub>4</sub>. The model predicted an optimal fluorination rate of 98.63 % when the material was roasted at 573 °C for 25 min with 59 % NaBF<sub>4</sub>. The clinker was acid-leached under optimal conditions (2.5 h at 80 °C with 9 M HCl and a liquid–solid ratio of 4 mL/g), and the Purity of fluorinated rare earths reached 99.39%. These results provide theoretical and experimental support for the application of pyrometallurgy in the recovery of rare-earth elements from NdFeB wastes.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106943"},"PeriodicalIF":4.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705094","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 : 2024-11-06DOI: 10.1016/j.ijrmhm.2024.106953
Liying Yao , Yuan He , Yimin Gao , Guojun Zhang
Y-Zr-O complex oxide dispersion-strengthened Mo alloys with different Zr contents (Mo-2Y2O3–0.6Zr, Mo-1Y2O3–0.6Zr, and Mo-1Y2O3–1.2Zr, wt%) were designed and fabricated by mechanical alloying and spark plasma sintering to investigate the effect of Zr addition on the microstructure and mechanical properties of this Mo alloy. The size and spatial distribution of oxide particles were characterized using Fresnel contrast mode in TEM, and mechanical properties were measured using small-scale three-point bending tests. Results show that Zr addition leads to the coarsening of oxide particles, especially intergranular particles. Based on Weibull theory, the strength ratio of Mo alloys in three-point bending and tensile tests is well fitted as 1.70. Furthermore, the Mo-2Y2O3–0.6Zr alloy exhibits an unprecedented tensile strength and fracture strain of 1059 MPa and 1.01 %, attributed to its ultrafine Mo grains (∼0.3 μm), semi-coherent intragranular oxide nanoprecipitates (∼18.09 nm), and intergranular oxide nanoprecipitates (∼67.11 nm). The theoretical calculation indicates that the strength is mainly affected by grain boundary strengthening and intragranular particle strengthening. The findings can provide a beneficial reference for the relationship between microstructure and mechanical properties of high-performance Mo alloy for nuclear energy applications.
{"title":"Effects of Zr addition on the microstructure and mechanical properties of Y-Zr-O complex oxide dispersion-strengthened Mo alloys","authors":"Liying Yao , Yuan He , Yimin Gao , Guojun Zhang","doi":"10.1016/j.ijrmhm.2024.106953","DOIUrl":"10.1016/j.ijrmhm.2024.106953","url":null,"abstract":"<div><div>Y-Zr-O complex oxide dispersion-strengthened Mo alloys with different Zr contents (Mo-2Y<sub>2</sub>O<sub>3</sub>–0.6Zr, Mo-1Y<sub>2</sub>O<sub>3</sub>–0.6Zr, and Mo-1Y<sub>2</sub>O<sub>3</sub>–1.2Zr, wt%) were designed and fabricated by mechanical alloying and spark plasma sintering to investigate the effect of Zr addition on the microstructure and mechanical properties of this Mo alloy. The size and spatial distribution of oxide particles were characterized using Fresnel contrast mode in TEM, and mechanical properties were measured using small-scale three-point bending tests. Results show that Zr addition leads to the coarsening of oxide particles, especially intergranular particles. Based on Weibull theory, the strength ratio of Mo alloys in three-point bending and tensile tests is well fitted as 1.70. Furthermore, the Mo-2Y<sub>2</sub>O<sub>3</sub>–0.6Zr alloy exhibits an unprecedented tensile strength and fracture strain of 1059 MPa and 1.01 %, attributed to its ultrafine Mo grains (∼0.3 μm), semi-coherent intragranular oxide nanoprecipitates (∼18.09 nm), and intergranular oxide nanoprecipitates (∼67.11 nm). The theoretical calculation indicates that the strength is mainly affected by grain boundary strengthening and intragranular particle strengthening. The findings can provide a beneficial reference for the relationship between microstructure and mechanical properties of high-performance Mo alloy for nuclear energy applications.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106953"},"PeriodicalIF":4.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593587","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 : 2024-11-03DOI: 10.1016/j.ijrmhm.2024.106949
N. Yurchenko , E. Panina , V. Mirontsov , D. Kapustin , M. Mishunin , S. Zherebtsov , N. Stepanov
Herein, structure, mechanical properties, and oxidation behaviour of a refractory (CrHfMoNbTaTiVZr)84Si16 complex concentrated alloy (RCCA) prepared by vacuum arc melting were studied. Consisting of C11b-MeSi2, C14 Laves, bcc, and Me5Si3 phases, the alloy exhibited better 1200 °C-specific yield strength (45 MPa cm3 g−1), fracture toughness (5.77 ± 1.58 MPa m1/2), and 1 h-mass gain at 1200 °C (∼60 mg cm−2) than most of current RCCAs.
本文研究了通过真空电弧熔炼制备的难熔（CrHfMoNbTaTiVZr）84Si16 复合浓缩合金（RCCA）的结构、力学性能和氧化行为。该合金由 C11b-MeSi2、C14 Laves、bcc 和 Me5Si3 相组成，与目前大多数 RCCA 相比，具有更好的 1200 °C 特定屈服强度（45 MPa cm3 g-1）、断裂韧性（5.77 ± 1.58 MPa m1/2）和 1200 °C 1 h 质量增益（60 mg cm-2）。
{"title":"Structure, mechanical properties, and oxidation behaviour of a refractory (CrHfMoNbTaTiVZr)84Si16 complex concentrated alloy","authors":"N. Yurchenko , E. Panina , V. Mirontsov , D. Kapustin , M. Mishunin , S. Zherebtsov , N. Stepanov","doi":"10.1016/j.ijrmhm.2024.106949","DOIUrl":"10.1016/j.ijrmhm.2024.106949","url":null,"abstract":"<div><div>Herein, structure, mechanical properties, and oxidation behaviour of a refractory (CrHfMoNbTaTiVZr)<sub>84</sub>Si<sub>16</sub> complex concentrated alloy (RCCA) prepared by vacuum arc melting were studied. Consisting of C11<sub>b</sub>-MeSi<sub>2</sub>, C14 Laves, bcc, and Me<sub>5</sub>Si<sub>3</sub> phases, the alloy exhibited better 1200 °C-specific yield strength (45 MPa cm<sup>3</sup> g<sup>−1</sup>), fracture toughness (5.77 ± 1.58 MPa m<sup>1/2</sup>), and 1 h-mass gain at 1200 °C (∼60 mg cm<sup>−2</sup>) than most of current RCCAs.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"126 ","pages":"Article 106949"},"PeriodicalIF":4.2,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578980","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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