Pub Date : 2024-11-08DOI: 10.1016/j.intermet.2024.108558
Xueting Zhao , Kun Zhang , Peng Liu , Qing Guo , Haoyu Wang , Yuanwen Feng , Bing Li
Mn3Pt metal compounds are promising candidates for barocaloric cooling applications for their high thermal conductivity and pressure sensitivity. However, they are constrained by low entropy change and large thermal hysteresis. This study investigates the effects of doping with carbon (C) and nitrogen (N) and substituting with germanium (Ge) on the structure, as well as the thermal and barocaloric effects of Mn3Pt. We found that N and C doping significantly reduces the phase transition temperature and improves pressure sensitivity, although at the cost of reduced entropy change. In contrast, Ge substitution increases the phase transition temperature and enhances the entropy change by 123 %, with Mn3Pt0.8Ge0.2 achieving a maximum entropy change of 22.7 J kg−1 K−1. Additionally, defects were introduced to reduce the phase transition nucleation driving force, thereby lowering the thermal hysteresis to 4 K. This work provides a strategy for the simultaneous optimization of entropy change and thermal hysteresis, advancing the development of efficient and tunable barocaloric materials.
{"title":"Simultaneous optimization of entropy changes and thermal hysteresis in barocaloric compound of Mn3Pt","authors":"Xueting Zhao , Kun Zhang , Peng Liu , Qing Guo , Haoyu Wang , Yuanwen Feng , Bing Li","doi":"10.1016/j.intermet.2024.108558","DOIUrl":"10.1016/j.intermet.2024.108558","url":null,"abstract":"<div><div>Mn<sub>3</sub>Pt metal compounds are promising candidates for barocaloric cooling applications for their high thermal conductivity and pressure sensitivity. However, they are constrained by low entropy change and large thermal hysteresis. This study investigates the effects of doping with carbon (C) and nitrogen (N) and substituting with germanium (Ge) on the structure, as well as the thermal and barocaloric effects of Mn<sub>3</sub>Pt. We found that N and C doping significantly reduces the phase transition temperature and improves pressure sensitivity, although at the cost of reduced entropy change. In contrast, Ge substitution increases the phase transition temperature and enhances the entropy change by 123 %, with Mn<sub>3</sub>Pt<sub>0.8</sub>Ge<sub>0.2</sub> achieving a maximum entropy change of 22.7 J kg<sup>−1</sup> K<sup>−1</sup>. Additionally, defects were introduced to reduce the phase transition nucleation driving force, thereby lowering the thermal hysteresis to 4 K. This work provides a strategy for the simultaneous optimization of entropy change and thermal hysteresis, advancing the development of efficient and tunable barocaloric materials.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108558"},"PeriodicalIF":4.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660104","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 : 2024-11-08DOI: 10.1016/j.intermet.2024.108557
Baolei Wu , Weiyuan Yu , Wenqi Zhu , Yang Li
Novel nano-multilayer foils composed of Ni/Al-Al-FeCo/CrNi filler metals were developed for brazing Al0.1CoCrFeNi alloys. These Ni/Al-FeCo/CrNi filler metals, designed using a high-entropy concept, were integrated to increase the mixing entropy and form solid solution structures. This strategic integration was aimed at preventing the formation of intermetallic compounds. The microstructural evolution and shear strength of the brazed joints were investigated by varying the holding time and brazing temperature. The results demonstrated the formation of a defect-free brazing joint, marked by the emergence of a solid solution structure resulting from the higher mixing entropy. With increasing temperature, the contribution of the solid-solution phase to the strengthening effect on the joint was more significant. The maximum shear strengths of the brazed joints were 308.5 MPa and 292.8 MPa at room temperature and 800 °C, respectively. Furthermore, the extended holding time and increased brazing temperature produced a steady increase in the shear strength of the joint with a corresponding transformation in the fracture mechanism from cleavage to ductility. This study introduces a novel process for brazing Al0.1CoCrFeNi and offers a technological paradigm for manufacturing industry at a high temperature (800 °C).
{"title":"A high-strength self-propagating-brazed Al0.1CoCrFeNi joint at high temperatures with nano-multilayer foils composed of Ni/Al-Al-FeCo/CrNi filler metal","authors":"Baolei Wu , Weiyuan Yu , Wenqi Zhu , Yang Li","doi":"10.1016/j.intermet.2024.108557","DOIUrl":"10.1016/j.intermet.2024.108557","url":null,"abstract":"<div><div>Novel nano-multilayer foils composed of Ni/Al-Al-FeCo/CrNi filler metals were developed for brazing Al<sub>0.1</sub>CoCrFeNi alloys. These Ni/Al-FeCo/CrNi filler metals, designed using a high-entropy concept, were integrated to increase the mixing entropy and form solid solution structures. This strategic integration was aimed at preventing the formation of intermetallic compounds. The microstructural evolution and shear strength of the brazed joints were investigated by varying the holding time and brazing temperature. The results demonstrated the formation of a defect-free brazing joint, marked by the emergence of a solid solution structure resulting from the higher mixing entropy. With increasing temperature, the contribution of the solid-solution phase to the strengthening effect on the joint was more significant. The maximum shear strengths of the brazed joints were 308.5 MPa and 292.8 MPa at room temperature and 800 °C, respectively. Furthermore, the extended holding time and increased brazing temperature produced a steady increase in the shear strength of the joint with a corresponding transformation in the fracture mechanism from cleavage to ductility. This study introduces a novel process for brazing Al<sub>0.1</sub>CoCrFeNi and offers a technological paradigm for manufacturing industry at a high temperature (800 °C).</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108557"},"PeriodicalIF":4.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660107","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.intermet.2024.108559
Z.L. Li , C.Y. Liu
In this study, Al-20 wt%Zn-x wt%Ce alloys (x = 0, 0.1, 0.5, and 1) were fabricated by casting, hot rolling, cold rolling, and solution treatment to investigate the effects of Ce content and rolling route on the microstructure and mechanical properties of high-Zn content Al-Zn-Ce alloys. Ce addition with weight ratio no higher than 0.5 % led to the formation of Al2CeZn2 phases in the Al-20Zn alloy, and the CeZn3 phases were obtained in this alloy when the Ce content increased to 1 %. Rolling effectively disrupted the Ce-containing phases, and the presence of these phases changed the grain structure of the Al-Zn-Ce alloys by affecting their deformation mode during rolling. Dynamic precipitation of Zn phases occurred in the Al-20Zn alloys during rolling. However, the Ce-containing phase consumed a large amount of Zn atoms, and then inhibited the dynamic precipitation of Zn phases in the studied alloys. The alloys with 0.5 wt%Ce addition exhibited the best mechanical properties, and the strengthening mechanism of the Al-Zn-Ce alloys were studied.
本研究通过铸造、热轧、冷轧和固溶处理制造了 Al-20 wt%Zn-x wt%Ce 合金（x = 0、0.1、0.5 和 1），以研究 Ce 含量和轧制路线对高锌含量 Al-Zn-Ce 合金微观结构和力学性能的影响。添加重量比不高于 0.5 % 的 Ce 会在 Al-20Zn 合金中形成 Al2CeZn2 相，当 Ce 含量增加到 1 % 时，合金中会出现 CeZn3 相。轧制有效地破坏了含 Ce 相，这些相的存在通过影响轧制过程中的变形模式改变了 Al-Zn-Ce 合金的晶粒结构。Al-20Zn 合金在轧制过程中发生了锌相的动态沉淀。然而，含 Ce 相消耗了大量 Zn 原子，从而抑制了所研究合金中 Zn 相的动态析出。添加了 0.5 wt%Ce 的合金具有最佳的机械性能，并对 Al-Zn-Ce 合金的强化机理进行了研究。
{"title":"Effect of Ce content and rolling route on the microstructure and mechanical properties of high-Zn content Al-Zn-Ce alloys","authors":"Z.L. Li , C.Y. Liu","doi":"10.1016/j.intermet.2024.108559","DOIUrl":"10.1016/j.intermet.2024.108559","url":null,"abstract":"<div><div>In this study, Al-20 wt%Zn-x wt%Ce alloys (x = 0, 0.1, 0.5, and 1) were fabricated by casting, hot rolling, cold rolling, and solution treatment to investigate the effects of Ce content and rolling route on the microstructure and mechanical properties of high-Zn content Al-Zn-Ce alloys. Ce addition with weight ratio no higher than 0.5 % led to the formation of Al<sub>2</sub>CeZn<sub>2</sub> phases in the Al-20Zn alloy, and the CeZn<sub>3</sub> phases were obtained in this alloy when the Ce content increased to 1 %. Rolling effectively disrupted the Ce-containing phases, and the presence of these phases changed the grain structure of the Al-Zn-Ce alloys by affecting their deformation mode during rolling. Dynamic precipitation of Zn phases occurred in the Al-20Zn alloys during rolling. However, the Ce-containing phase consumed a large amount of Zn atoms, and then inhibited the dynamic precipitation of Zn phases in the studied alloys. The alloys with 0.5 wt%Ce addition exhibited the best mechanical properties, and the strengthening mechanism of the Al-Zn-Ce alloys were studied.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108559"},"PeriodicalIF":4.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660110","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 : 2024-11-05DOI: 10.1016/j.intermet.2024.108549
Jinpeng Zhang, Qingyao Wu, Chuanlong Yang, Zhenhua Yang, Bingbing Yin, Yi Yang
AlCrMoNbTi high entropy alloy (HEA) has the potential to be an excellent oxidation-resistant refractory high entropy alloy (RHEA) but has been limited by an undesirable oxide layer structure. In this work, the initial oxidation behavior of AlCrMoNbTi HEA was investigated by a combination of experiments and DFT calculations. The results indicate that O atoms tend to occupy the adsorption sites containing Ti atoms. Consequently, Ti atoms are more prone to combine with O atoms, resulting in the formation of compounds, which impedes the formation of protective oxides, such as Al2O3 and Cr2O3. Meanwhile, calculations indicate that Cr atoms can form stable Cr-O bonds in a Ti-rich environment, which can be exploited to improve oxidation resistance by modifying the Cr-rich oxide layer.
AlCrMoNbTi 高熵合金 (HEA) 有潜力成为一种出色的抗氧化难熔高熵合金 (RHEA)，但一直受到不良氧化层结构的限制。在这项工作中，通过实验和 DFT 计算相结合的方法研究了 AlCrMoNbTi HEA 的初始氧化行为。结果表明，O 原子倾向于占据含有 Ti 原子的吸附位点。因此，Ti 原子更容易与 O 原子结合，形成化合物，从而阻碍 Al2O3 和 Cr2O3 等保护性氧化物的形成。同时，计算表明，Cr 原子可在富含 Ti 的环境中形成稳定的 Cr-O 键，可通过改变富含 Cr 的氧化物层来提高抗氧化性。
{"title":"Initial oxidation behavior of AlCrMoNbTi high-entropy alloys studied by DFT calculations and experiments","authors":"Jinpeng Zhang, Qingyao Wu, Chuanlong Yang, Zhenhua Yang, Bingbing Yin, Yi Yang","doi":"10.1016/j.intermet.2024.108549","DOIUrl":"10.1016/j.intermet.2024.108549","url":null,"abstract":"<div><div>AlCrMoNbTi high entropy alloy (HEA) has the potential to be an excellent oxidation-resistant refractory high entropy alloy (RHEA) but has been limited by an undesirable oxide layer structure. In this work, the initial oxidation behavior of AlCrMoNbTi HEA was investigated by a combination of experiments and DFT calculations. The results indicate that O atoms tend to occupy the adsorption sites containing Ti atoms. Consequently, Ti atoms are more prone to combine with O atoms, resulting in the formation of compounds, which impedes the formation of protective oxides, such as Al<sub>2</sub>O<sub>3</sub> and Cr<sub>2</sub>O<sub>3</sub>. Meanwhile, calculations indicate that Cr atoms can form stable Cr-O bonds in a Ti-rich environment, which can be exploited to improve oxidation resistance by modifying the Cr-rich oxide layer.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108549"},"PeriodicalIF":4.3,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586870","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 : 2024-11-05DOI: 10.1016/j.intermet.2024.108550
Qian Liang, Yaqi Wang, Chendong Shao, Yueqiao Feng, Fenggui Lu
In this study, CuCrZr-Hastelloy X bimetallic structure featuring an ultra-fine grain zone (UFGZ) near the interface were fabricated by laser-directed energy deposition (L-DED). Samples with UFGZ were obtained with 300 °C preheating, whereas samples without preheating did not contain UFGZ. The microstructures and mechanical properties of samples with and without UFGZ were compared. The formation of UFGZ was attributed to the presence of a spherical phase near the interface, which was identified as Ni (Fe, Cr, Mo). Due to the higher melting point of Hastelloy X compared to CuCrZr, Ni elements mixed into CuCrZr with the flow of the molten pool, solidified first, and served as substrates for the heterogeneous nucleation, ultimately promoting the formation of UFGZ. With 300 °C preheating, the hardness of CuCrZr near the interface increased from 115.07 HV to 148.51 HV due to the presence of UFGZ. And the hardness gap near the interface decreased from 172.58 HV to 147.19 HV, which improved the uniformity of mechanical properties. Moreover, the nanoindentation tests results that UFGZ increased the hardness of the zone near the interface from 1.42 GPa to 1.72 GPa. Tensile test results indicated that the UFGZ altered the fracture mode from brittle to ductile. Samples with UFGZ exhibited ductile fracture, while those without UFGZ exhibited brittle fracture. At room temperature, the tensile strength of samples with UFGZ increased from 298.44 MPa to 347.05 MPa. For tests conducted at 400 °C, the tensile strength increased from 165.12 MPa to 229.53 MPa. This enhancement indicated that UFGZ could improve the strength and toughness of the interface, thereby enhancing the interfacial bonding strength. This study is of great significance for improving the interfacial bonding strength of CuCrZr-Hastelloy X bimetallic structures.
{"title":"Effect of ultra-fine grain zone on mechanical properties of CuCrZr-Hastelloy X bimetallic structure manufactured by laser-directed energy deposition","authors":"Qian Liang, Yaqi Wang, Chendong Shao, Yueqiao Feng, Fenggui Lu","doi":"10.1016/j.intermet.2024.108550","DOIUrl":"10.1016/j.intermet.2024.108550","url":null,"abstract":"<div><div>In this study, CuCrZr-Hastelloy X bimetallic structure featuring an ultra-fine grain zone (UFGZ) near the interface were fabricated by laser-directed energy deposition (L-DED). Samples with UFGZ were obtained with 300 °C preheating, whereas samples without preheating did not contain UFGZ. The microstructures and mechanical properties of samples with and without UFGZ were compared. The formation of UFGZ was attributed to the presence of a spherical phase near the interface, which was identified as Ni (Fe, Cr, Mo). Due to the higher melting point of Hastelloy X compared to CuCrZr, Ni elements mixed into CuCrZr with the flow of the molten pool, solidified first, and served as substrates for the heterogeneous nucleation, ultimately promoting the formation of UFGZ. With 300 °C preheating, the hardness of CuCrZr near the interface increased from 115.07 HV to 148.51 HV due to the presence of UFGZ. And the hardness gap near the interface decreased from 172.58 HV to 147.19 HV, which improved the uniformity of mechanical properties. Moreover, the nanoindentation tests results that UFGZ increased the hardness of the zone near the interface from 1.42 GPa to 1.72 GPa. Tensile test results indicated that the UFGZ altered the fracture mode from brittle to ductile. Samples with UFGZ exhibited ductile fracture, while those without UFGZ exhibited brittle fracture. At room temperature, the tensile strength of samples with UFGZ increased from 298.44 MPa to 347.05 MPa. For tests conducted at 400 °C, the tensile strength increased from 165.12 MPa to 229.53 MPa. This enhancement indicated that UFGZ could improve the strength and toughness of the interface, thereby enhancing the interfacial bonding strength. This study is of great significance for improving the interfacial bonding strength of CuCrZr-Hastelloy X bimetallic structures.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108550"},"PeriodicalIF":4.3,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592697","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 : 2024-11-04DOI: 10.1016/j.intermet.2024.108553
Han Hu , Fangjie Li , Min Liu , Dongye Yang , Zongxin Zhu , Qin Shen , Zhigang Yu
This study examined both theoretically and experimentally the oxidation behavior of AlCoCr0.5Fe2.5Ni2.5 and Al0.25CoCrFeNi alloys in the time for 10 h and 180 h at 800 °C in air atmosphere. The results showed that the weight gain of the dual-phase AlCoCr0.5Fe2.5Ni2.5 alloy followed the parabolic rate law, while this value persisted almost unchanged for the single-phase Al0.25CoCrFeNi alloy at the same oxidizing condition. Surface analysis of the oxide scale confirmed the formation of Al2O3, Cr2O3 and Fe3O4 oxides. Comparing the experimental results with thermodynamic models and Density functional theory (DFT) calculations suggests that Al and Cr are first oxidized in the AlCoCr0.5Fe2.5Ni2.5 and Al0.25CoCrFeNi alloys, respectively, then outer Fe3O4 scale appeared in the two alloys. The weak resistance to high temperature oxidation of AlCoCr0.5Fe2.5Ni2.5 alloy was mainly ascribed to its high fraction of grain and phase boundaries, as well as the fragmented oxide layer formed due to enhanced element diffusion at the FCC/BCC phase boundaries. The element migration and oxidation process of oxide layers in the two alloys were declared based on thermodynamic and DFT calculations.
{"title":"High temperature oxidation behavior of the dual-phase AlCoCr0.5Fe2.5Ni2.5 and single phase Al0.25CoCrFeNi high entropy alloys","authors":"Han Hu , Fangjie Li , Min Liu , Dongye Yang , Zongxin Zhu , Qin Shen , Zhigang Yu","doi":"10.1016/j.intermet.2024.108553","DOIUrl":"10.1016/j.intermet.2024.108553","url":null,"abstract":"<div><div>This study examined both theoretically and experimentally the oxidation behavior of AlCoCr<sub>0.5</sub>Fe<sub>2.5</sub>Ni<sub>2.5</sub> and Al<sub>0.25</sub>CoCrFeNi alloys in the time for 10 h and 180 h at 800 °C in air atmosphere. The results showed that the weight gain of the dual-phase AlCoCr<sub>0.5</sub>Fe<sub>2.5</sub>Ni<sub>2.5</sub> alloy followed the parabolic rate law, while this value persisted almost unchanged for the single-phase Al<sub>0.25</sub>CoCrFeNi alloy at the same oxidizing condition. Surface analysis of the oxide scale confirmed the formation of Al<sub>2</sub>O<sub>3</sub>, Cr<sub>2</sub>O<sub>3</sub> and Fe<sub>3</sub>O<sub>4</sub> oxides. Comparing the experimental results with thermodynamic models and Density functional theory (DFT) calculations suggests that Al and Cr are first oxidized in the AlCoCr<sub>0.5</sub>Fe<sub>2.5</sub>Ni<sub>2.5</sub> and Al<sub>0.25</sub>CoCrFeNi alloys, respectively, then outer Fe<sub>3</sub>O<sub>4</sub> scale appeared in the two alloys. The weak resistance to high temperature oxidation of AlCoCr<sub>0.5</sub>Fe<sub>2.5</sub>Ni<sub>2.5</sub> alloy was mainly ascribed to its high fraction of grain and phase boundaries, as well as the fragmented oxide layer formed due to enhanced element diffusion at the FCC/BCC phase boundaries. The element migration and oxidation process of oxide layers in the two alloys were declared based on thermodynamic and DFT calculations.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108553"},"PeriodicalIF":4.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578394","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}
During the investigation of the Cu-As-Sb ternary system, we identified the ternary intermetallic Cu3−x(As,Sb) compound. Its crystal structure was solved and refined by single crystal and powder X-ray diffraction. While the binary Cu3−xAs and Cu3−xSb phases crystallize in the hexagonal Cu3P-type (hP24, P63cm) and cubic anti-BiF3-type (cF16, Fmm), respectively, Cu3−x(As,Sb) adopts the cubic Cu6AsSb prototype (cP32, Pmn). Crystallochemical reasons lead to the exclusion that its structure could be of the UH3-type. Cu3−x(As,Sb) is isotypic with Cu12−xTeSb3; their crystal structure is a stuffed ternary derivative of the Cr3Si-type. SEM-EDX analyses reveal very large compositional ranges for this compound, mostly concerning the Sb/As ratio: 71.1−73.9 at.% Cu, 4.0−24.5 at.% As and 2.5−23.5 at.% Sb, corresponding to about Cu2.5-2.8As0.23-0.98Sb0.23-0.92 (x = 0.2−0.5). The lattice parameter and, consequently, the unit cell volume regularly expand while increasing the Sb/As compositional ratio: a ≈ 7.47 Å for Cu3−xAs0.75Sb0.25, a ≈ 7.65 Å for Cu3−xAs0.25Sb0.75 (averaged values).
Cu3−x(As,Sb) forms either by a peritectic reaction for As-rich compositions, or congruently for the equiatomic Sb/As and Sb-rich compositions. The decomposition- or melting-temperature values decrease as a function of the Sb/As compositional ratio [e.g. peritectic at 710 °C for Cu3−xAs0.75Sb0.25 (Cu72As21Sb7), congruent melting at 690 °C for Cu3−xAs0.50Sb0.50 (Cu72As14Sb14), and at 675 °C for Cu3−xAs0.25Sb0.75 (Cu72As7Sb21)].
Physical properties (electrical resistivity and magnetic susceptibility) indicate that Cu3−x(As,Sb) behaves as a good metal with electrical resistivity decreasing as the Sb/As compositional ratio increases; a peculiar anomaly in the electrical resistivity behavior (heavy-fermions like) was observed at low temperature, the origin of which needs further investigation. The compound is a standard diamagnet.
{"title":"Crystallochemistry, thermodynamic and physical properties of the intermetallic compound Cu3−x(As,Sb)","authors":"Marianne Mödlinger , Alessia Provino , Pavlo Solokha , Serena De Negri , Federico Caglieris , Michele Ceccardi , Cristina Bernini , Pietro Manfrinetti","doi":"10.1016/j.intermet.2024.108526","DOIUrl":"10.1016/j.intermet.2024.108526","url":null,"abstract":"<div><div>During the investigation of the Cu-As-Sb ternary system, we identified the ternary intermetallic Cu<sub>3−x</sub>(As,Sb) compound. Its crystal structure was solved and refined by single crystal and powder X-ray diffraction. While the binary Cu<sub>3−x</sub>As and Cu<sub>3−x</sub>Sb phases crystallize in the hexagonal Cu<sub>3</sub>P-type (<em>hP</em>24, <em>P</em>6<sub>3</sub><em>cm</em>) and cubic anti-BiF<sub>3</sub>-type (<em>cF</em>16, <em>Fm</em><span><math><mover><mn>3</mn><mo>¯</mo></mover></math></span><em>m</em>), respectively, Cu<sub>3−x</sub>(As,Sb) adopts the cubic Cu<sub>6</sub>AsSb prototype (<em>cP</em>32, <em>Pm</em><span><math><mrow><mover><mn>3</mn><mo>‾</mo></mover></mrow></math></span><em>n</em>). Crystallochemical reasons lead to the exclusion that its structure could be of the UH<sub>3</sub>-type. Cu<sub>3−x</sub>(As,Sb) is isotypic with Cu<sub>12−x</sub>TeSb<sub>3</sub>; their crystal structure is a stuffed ternary derivative of the Cr<sub>3</sub>Si-type. SEM-EDX analyses reveal very large compositional ranges for this compound, mostly concerning the Sb/As ratio: 71.1−73.9 at.% Cu, 4.0−24.5 at.% As and 2.5−23.5 at.% Sb, corresponding to about Cu<sub>2.5-2.8</sub>As<sub>0.23-0.98</sub>Sb<sub>0.23-0.92</sub> (x = 0.2−0.5). The lattice parameter and, consequently, the unit cell volume regularly expand while increasing the Sb/As compositional ratio: <em>a</em> ≈ 7.47 Å for Cu<sub>3−x</sub>As<sub>0.75</sub>Sb<sub>0.25</sub>, <em>a</em> ≈ 7.65 Å for Cu<sub>3−x</sub>As<sub>0.25</sub>Sb<sub>0.75</sub> (averaged values).</div><div>Cu<sub>3−x</sub>(As,Sb) forms either by a peritectic reaction for As-rich compositions, or congruently for the equiatomic Sb/As and Sb-rich compositions. The decomposition- or melting-temperature values decrease as a function of the Sb/As compositional ratio [<em>e.g</em>. peritectic at 710 °C for Cu<sub>3−x</sub>As<sub>0.75</sub>Sb<sub>0.25</sub> (Cu<sub>72</sub>As<sub>21</sub>Sb<sub>7</sub>), congruent melting at 690 °C for Cu<sub>3−x</sub>As<sub>0.50</sub>Sb<sub>0.50</sub> (Cu<sub>72</sub>As<sub>14</sub>Sb<sub>14</sub>), and at 675 °C for Cu<sub>3−x</sub>As<sub>0.25</sub>Sb<sub>0.75</sub> (Cu<sub>72</sub>As<sub>7</sub>Sb<sub>21</sub>)].</div><div>Physical properties (electrical resistivity and magnetic susceptibility) indicate that Cu<sub>3−x</sub>(As,Sb) behaves as a good metal with electrical resistivity decreasing as the Sb/As compositional ratio increases; a peculiar anomaly in the electrical resistivity behavior (heavy-fermions like) was observed at low temperature, the origin of which needs further investigation. The compound is a standard diamagnet.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108526"},"PeriodicalIF":4.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571854","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 : 2024-10-31DOI: 10.1016/j.intermet.2024.108538
Xuesong Xu , He Liang , Hongsheng Ding , Karl P. Davidson , R.V. Ramanujan , Ruirun Chen , Jingjie Guo , Hengzhi Fu
The high temperature oxidation behavior and mechanical property response of a directionally solidified Ti-46Al-7Nb-0.4W-0.6Cr-0.1B alloy were investigated. The ultimate tensile strength of the alloy at 800 °C, 850 °C and 900 °C are 647 MPa, 590 MPa and 508 MPa, respectively, and the tensile fracture mode changed from brittle cleavage fracture to micro-void accumulation ductile fracture. At lower temperatures Al2O3 forms first, growing along the γ lamellae to form oxide bands aligned with the lamellar orientation. The oxidation mass gain of the alloy after 900 °C/100 h isothermal oxidation is only 0.91 mg/cm2. The oxidation kinetics results show the microalloyed high Nb TiAl alloy has excellent oxidation resistance, which is due to the formation of a TiO2 layer containing Nb, Cr and W, the AlNb2 phase and an Al/Cr rich transition layer above the directionally solidified lamellar matrix.
研究了定向凝固 Ti-46Al-7Nb-0.4W-0.6Cr-0.1B 合金的高温氧化行为和力学性能响应。合金在 800 ℃、850 ℃ 和 900 ℃ 时的极限拉伸强度分别为 647 MPa、590 MPa 和 508 MPa，拉伸断裂模式从脆性劈裂断裂转变为微空洞堆积韧性断裂。在较低温度下，Al2O3 首先形成，沿着 γ 薄片生长，形成与薄片取向一致的氧化带。合金在 900 °C/100 h 等温氧化后的氧化质量增量仅为 0.91 mg/cm2。氧化动力学结果表明，微合金化高 Nb TiAl 合金具有优异的抗氧化性，这是由于在定向凝固的片状基体上方形成了含有 Nb、Cr 和 W 的 TiO2 层、AlNb2 相和富 Al/Cr 过渡层。
{"title":"Oxidation behavior and mechanical properties of a directionally solidified high Nb TiAl based alloy between 800 °C and 900 °C","authors":"Xuesong Xu , He Liang , Hongsheng Ding , Karl P. Davidson , R.V. Ramanujan , Ruirun Chen , Jingjie Guo , Hengzhi Fu","doi":"10.1016/j.intermet.2024.108538","DOIUrl":"10.1016/j.intermet.2024.108538","url":null,"abstract":"<div><div>The high temperature oxidation behavior and mechanical property response of a directionally solidified Ti-46Al-7Nb-0.4W-0.6Cr-0.1B alloy were investigated. The ultimate tensile strength of the alloy at 800 °C, 850 °C and 900 °C are 647 MPa, 590 MPa and 508 MPa, respectively, and the tensile fracture mode changed from brittle cleavage fracture to micro-void accumulation ductile fracture. At lower temperatures Al<sub>2</sub>O<sub>3</sub> forms first, growing along the γ lamellae to form oxide bands aligned with the lamellar orientation. The oxidation mass gain of the alloy after 900 °C/100 h isothermal oxidation is only 0.91 mg/cm<sup>2</sup>. The oxidation kinetics results show the microalloyed high Nb TiAl alloy has excellent oxidation resistance, which is due to the formation of a TiO<sub>2</sub> layer containing Nb, Cr and W, the AlNb<sub>2</sub> phase and an Al/Cr rich transition layer above the directionally solidified lamellar matrix.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"176 ","pages":"Article 108538"},"PeriodicalIF":4.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571853","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 : 2024-10-30DOI: 10.1016/j.intermet.2024.108547
Xiang Gao , Aili Tao , Mingcong Zou , Zaidong Xu
In this paper, a new type of Ti-8V-4Mo-3Cr-3Zr-3Al metastable β-type titanium alloy is designed based on alloy design parameters such as valence electron concentration (VEC), Bo, and Md, and combines them with the empirical criterion of molybdenum equivalent fractionation. Optimize the microstructure of the alloy through processes such as cold rolling, annealing, and aging treatment to obtain good mechanical properties. The microstructure of cold rolling and post rolling heat treatment was observed and analyzed using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM), and the tensile properties of the alloy were tested. The characteristics of the alloy in terms of microstructure and properties were summarized and analyzed. The results show that the cold formability of the alloy after solid solution treatment is good, with a cold rolling reduction of over 85 %, and a large number of deformation twins generated during the cold rolling process. The yield strength after annealing and recrystallization is up to 1160 MPa, and elongation is 18.9 %. The final performance of the aged alloy is 1510 MPa for yield strength and 5 % for elongation.
{"title":"Research on the microstructure and properties of metastable β type Ti-8V4Mo3Cr3Zr3Al alloy with high strength and toughness","authors":"Xiang Gao , Aili Tao , Mingcong Zou , Zaidong Xu","doi":"10.1016/j.intermet.2024.108547","DOIUrl":"10.1016/j.intermet.2024.108547","url":null,"abstract":"<div><div>In this paper, a new type of Ti-8V-4Mo-3Cr-3Zr-3Al metastable β-type titanium alloy is designed based on alloy design parameters such as valence electron concentration (VEC), <em>Bo</em>, and <em>Md</em>, and combines them with the empirical criterion of molybdenum equivalent fractionation. Optimize the microstructure of the alloy through processes such as cold rolling, annealing, and aging treatment to obtain good mechanical properties. The microstructure of cold rolling and post rolling heat treatment was observed and analyzed using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM), and the tensile properties of the alloy were tested. The characteristics of the alloy in terms of microstructure and properties were summarized and analyzed. The results show that the cold formability of the alloy after solid solution treatment is good, with a cold rolling reduction of over 85 %, and a large number of deformation twins generated during the cold rolling process. The yield strength after annealing and recrystallization is up to 1160 MPa, and elongation is 18.9 %. The final performance of the aged alloy is 1510 MPa for yield strength and 5 % for elongation.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108547"},"PeriodicalIF":4.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554515","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 : 2024-10-30DOI: 10.1016/j.intermet.2024.108544
Qi Zhang , Kaihong Zheng , Juan Wang , Xianzhu Qin
Reliable brazing joints of Al2O3 ceramics were obtained using an active Ni‒Ti interlayer under vacuum conditions. The interfacial microstructure and mechanical properties of the joints were studied. The structural, electronic, and elastic properties of the primary interfacial reaction phases were determined using first–principles calculations. After brazing at 1320 °C for 30 min, Ni2Ti4O layer and columnar AlNi2Ti formed at the interface adjacent to the Al2O3 substrate. With increasing brazing temperature between 1300 °C and 1380 °C, Ni2Ti4O layer thickened gradually, and the AlNi2Ti became increasingly longer. As brazing temperature reached 1400 °C, TiO was formed at the interface, and the Ni2Ti4O content decreased significantly; moreover, bulk AlNi2Ti and TiNi3 were distributed in the brazing seam. The highest shear strength of 129 MPa was achieved when brazed at 1350 °C for 30 min. According to the first–principles calculations, Ni2Ti4O is more readily formed than AlNi2Ti, whereas AlNi2Ti exhibits greater stability than Ni2Ti4O. Both AlNi2Ti and Ni2Ti4O possess metallic bonds, contributing to the adhesion of the filler metal to the Al2O3 substrates. The calculated modulus and Poisson’s ratio indicate that both AlNi2Ti and Ni2Ti4O exhibit ductile characteristics, which assist in relieving residual stress within the joint.
{"title":"Interfacial microstructure evolution and mechanical characterization of brazed Al2O3 joints with Ni‒Ti interlayer: An experimental and theoretical approach","authors":"Qi Zhang , Kaihong Zheng , Juan Wang , Xianzhu Qin","doi":"10.1016/j.intermet.2024.108544","DOIUrl":"10.1016/j.intermet.2024.108544","url":null,"abstract":"<div><div>Reliable brazing joints of Al<sub>2</sub>O<sub>3</sub> ceramics were obtained using an active Ni‒Ti interlayer under vacuum conditions. The interfacial microstructure and mechanical properties of the joints were studied. The structural, electronic, and elastic properties of the primary interfacial reaction phases were determined using first–principles calculations. After brazing at 1320 °C for 30 min, Ni<sub>2</sub>Ti<sub>4</sub>O layer and columnar AlNi<sub>2</sub>Ti formed at the interface adjacent to the Al<sub>2</sub>O<sub>3</sub> substrate. With increasing brazing temperature between 1300 °C and 1380 °C, Ni<sub>2</sub>Ti<sub>4</sub>O layer thickened gradually, and the AlNi<sub>2</sub>Ti became increasingly longer. As brazing temperature reached 1400 °C, TiO was formed at the interface, and the Ni<sub>2</sub>Ti<sub>4</sub>O content decreased significantly; moreover, bulk AlNi<sub>2</sub>Ti and TiNi<sub>3</sub> were distributed in the brazing seam. The highest shear strength of 129 MPa was achieved when brazed at 1350 °C for 30 min. According to the first–principles calculations, Ni<sub>2</sub>Ti<sub>4</sub>O is more readily formed than AlNi<sub>2</sub>Ti, whereas AlNi<sub>2</sub>Ti exhibits greater stability than Ni<sub>2</sub>Ti<sub>4</sub>O. Both AlNi<sub>2</sub>Ti and Ni<sub>2</sub>Ti<sub>4</sub>O possess metallic bonds, contributing to the adhesion of the filler metal to the Al<sub>2</sub>O<sub>3</sub> substrates. The calculated modulus and Poisson’s ratio indicate that both AlNi<sub>2</sub>Ti and Ni<sub>2</sub>Ti<sub>4</sub>O exhibit ductile characteristics, which assist in relieving residual stress within the joint.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108544"},"PeriodicalIF":4.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554514","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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