Pub Date : 2024-10-17DOI: 10.1016/j.intermet.2024.108533
Jian Yang , Feifei Zhang , Lihong Zhai , Guofeng Qu , Jijun Yang
The FeCrAlTiMo high-entropy alloy (HEA) coatings were deposited on the ferritic/martensitic (F/M) steel fuel cladding tubes by magnetron sputtering technology to improve their lead-bismuth eutectic (LBE) corrosion resistance. The effects of bias voltage on the microstructure, mechanical and LBE corrosion properties of the FeCrAlTiMo coatings were systematically investigated. The LBE corrosion test shows that the coatings with a bias voltage of −150 V exhibit the best oxidation resistance after exposed to the oxygen-deficient LBE at 600 °C for 500 h, and can be used as a protective candidate coating material for lead-cooled fast reactor (LFR) application. The high-temperature LBE corrosion mechanism of the FeCrAlTiMo coatings under deficient oxygen concentration was also discussed in detail.
采用磁控溅射技术在铁素体/马氏体（F/M）钢燃料包壳管上沉积了铁铬铝钛钼高熵合金（HEA）涂层，以提高其铅铋共晶（LBE）耐腐蚀性。系统研究了偏压对 FeCrAlTiMo 涂层的微观结构、机械性能和 LBE 腐蚀性能的影响。LBE 腐蚀试验表明，偏置电压为 -150 V 的涂层在 600 °C 的缺氧 LBE 下暴露 500 小时后表现出最佳的抗氧化性，可用作铅冷快堆 (LFR) 应用的保护性候选涂层材料。此外，还详细讨论了缺氧条件下铁铬铝钛钼涂层的高温 LBE 腐蚀机理。
{"title":"Microstructure, mechanical and oxygen-deficient lead-bismuth eutectic corrosion properties of FeCrAlTiMo high-entropy alloy coatings for fuel claddings","authors":"Jian Yang , Feifei Zhang , Lihong Zhai , Guofeng Qu , Jijun Yang","doi":"10.1016/j.intermet.2024.108533","DOIUrl":"10.1016/j.intermet.2024.108533","url":null,"abstract":"<div><div>The FeCrAlTiMo high-entropy alloy (HEA) coatings were deposited on the ferritic/martensitic (F/M) steel fuel cladding tubes by magnetron sputtering technology to improve their lead-bismuth eutectic (LBE) corrosion resistance. The effects of bias voltage on the microstructure, mechanical and LBE corrosion properties of the FeCrAlTiMo coatings were systematically investigated. The LBE corrosion test shows that the coatings with a bias voltage of −150 V exhibit the best oxidation resistance after exposed to the oxygen-deficient LBE at 600 °C for 500 h, and can be used as a protective candidate coating material for lead-cooled fast reactor (LFR) application. The high-temperature LBE corrosion mechanism of the FeCrAlTiMo coatings under deficient oxygen concentration was also discussed in detail.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108533"},"PeriodicalIF":4.3,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446588","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 : 2024-10-17DOI: 10.1016/j.intermet.2024.108527
Weiming Huang , Lilin Wang , Haozhi Chai , Xin Lin
The influence of alloying on the microstructure, particularly the phase precipitation behavior and the volume fraction of the γʹ phase, is critical for the development of precipitation-strengthed cobalt-based superalloys. In the context of additive manufacturing, it is also essential to consider how alloying elements affect the formability of these alloys. In this study, three developed CoNi-based superalloys, named as AlTa, AlTaNb and AlTaTi, were fabricated using laser directed energy deposition, and followed by homogenization and aging treatment. The effect of alloy composition on additive manufacturing formability, microstructure and mechanical properties was analyzed. The AlTa and AlTaNb specimens show good additive manufacturing formability, but the AlTaTi specimen appears several long cracks along deposition direction. The addition of Ti is not conducive to the additive manufacturing formability of CoNi-based superalloys. The volume fraction of the γ′ phase in the three heat-treated specimens is 65∼70 %, and the average size is about 200 nm. The AlTa specimen maintains its tensile strength without softening from room temperature to 900 °C, possessing an excellent yield strength of 471 MPa at 900 °C. The AlTaNb and AlTaTi specimens achieves higher tensile strength at room temperature due to the strengthening effect of Nb and Ti elements, but underwent premature intergranular fracture during high-temperature tensile testing due to the insufficient grain boundary strength. Futher grain boundary strengthening should be considered for them.
{"title":"Effects of Ta/Nb/Ti addition on the microstructure and mechanical properties of novel CoNi-based superalloys fabricated by directed energy deposition","authors":"Weiming Huang , Lilin Wang , Haozhi Chai , Xin Lin","doi":"10.1016/j.intermet.2024.108527","DOIUrl":"10.1016/j.intermet.2024.108527","url":null,"abstract":"<div><div>The influence of alloying on the microstructure, particularly the phase precipitation behavior and the volume fraction of the γʹ phase, is critical for the development of precipitation-strengthed cobalt-based superalloys. In the context of additive manufacturing, it is also essential to consider how alloying elements affect the formability of these alloys. In this study, three developed CoNi-based superalloys, named as AlTa, AlTaNb and AlTaTi, were fabricated using laser directed energy deposition, and followed by homogenization and aging treatment. The effect of alloy composition on additive manufacturing formability, microstructure and mechanical properties was analyzed. The AlTa and AlTaNb specimens show good additive manufacturing formability, but the AlTaTi specimen appears several long cracks along deposition direction. The addition of Ti is not conducive to the additive manufacturing formability of CoNi-based superalloys. The volume fraction of the γ′ phase in the three heat-treated specimens is 65∼70 %, and the average size is about 200 nm. The AlTa specimen maintains its tensile strength without softening from room temperature to 900 °C, possessing an excellent yield strength of 471 MPa at 900 °C. The AlTaNb and AlTaTi specimens achieves higher tensile strength at room temperature due to the strengthening effect of Nb and Ti elements, but underwent premature intergranular fracture during high-temperature tensile testing due to the insufficient grain boundary strength. Futher grain boundary strengthening should be considered for them.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108527"},"PeriodicalIF":4.3,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446587","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 : 2024-10-14DOI: 10.1016/j.intermet.2024.108525
Tao Huang , Qiquan Cheng , Qinpei Liu , Junpeng Wei , Chang Han , Yanyan Huang , Jiankun Xiong , Jianping Yang , Yang Guo , Xia Li , Xiaowu Luo , Qinghua Zhou
The influence of the applied tensile elastic stresses on the corrosion behavior of GH4169 Ni-based superalloy, 75 wt% Na2SO4 + 25 wt% NaCl salt, 650 or 850 °C and 24 h, is investigated. The corrosion surface tend to exhibit serious peeling of the oxide scale and uneven morphology when stress applied, and the main corrosion products are identical with or without stress. With the increment in stress, the corrosion layer deepens, and more voids (or cracks) can be observed and their distribution as a function of stress and corrosion depth is further discussed with respect to linear density. Apart from the transverse extension of the corrosion area from grain boundaries to grain interior, the stress enhanced corrosion also demonstrates longitudinal extension along grain boundaries perpendicular to the stress direction into the alloy interior. Local mechanical properties in thermal etched region obtained by nanoindentation demonstrate that the alloy yields worse properties resulted from the negative effect of high stress and hot corrosion on internal microstructure. The mechanism of stress enhanced hot corrosion is further analyzed combining both experimental and molecular dynamics simulation results with respect to vacancies, distribution and bonding situation of atoms, and morphology and thickness of the transition layer.
{"title":"Effect of external stress on the high-temperature corrosion behavior of GH4169 alloy","authors":"Tao Huang , Qiquan Cheng , Qinpei Liu , Junpeng Wei , Chang Han , Yanyan Huang , Jiankun Xiong , Jianping Yang , Yang Guo , Xia Li , Xiaowu Luo , Qinghua Zhou","doi":"10.1016/j.intermet.2024.108525","DOIUrl":"10.1016/j.intermet.2024.108525","url":null,"abstract":"<div><div>The influence of the applied tensile elastic stresses on the corrosion behavior of GH4169 Ni-based superalloy, 75 wt% Na<sub>2</sub>SO<sub>4</sub> + 25 wt% NaCl salt, 650 or 850 °C and 24 h, is investigated. The corrosion surface tend to exhibit serious peeling of the oxide scale and uneven morphology when stress applied, and the main corrosion products are identical with or without stress. With the increment in stress, the corrosion layer deepens, and more voids (or cracks) can be observed and their distribution as a function of stress and corrosion depth is further discussed with respect to linear density. Apart from the transverse extension of the corrosion area from grain boundaries to grain interior, the stress enhanced corrosion also demonstrates longitudinal extension along grain boundaries perpendicular to the stress direction into the alloy interior. Local mechanical properties in thermal etched region obtained by nanoindentation demonstrate that the alloy yields worse properties resulted from the negative effect of high stress and hot corrosion on internal microstructure. The mechanism of stress enhanced hot corrosion is further analyzed combining both experimental and molecular dynamics simulation results with respect to vacancies, distribution and bonding situation of atoms, and morphology and thickness of the transition layer.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108525"},"PeriodicalIF":4.3,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433220","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 : 2024-10-14DOI: 10.1016/j.intermet.2024.108513
Sourav Ghosh , Hemanth Kumar , Christian Brandl , Abhik N. Choudhury , Saswata Bhattacharyya , Rajdip Mukherjee
Inconel 740H (IN740H) has emerged as an important candidate for the advanced ultra-supercritical (AUSC) steam turbines due to its superior microstructural stability and creep resistance under service conditions. In the present work, we have reparameterized a multicomponent Ni-based superalloy (IN740H) into an equivalent ternary Ni-Al-Mo superalloy, based on the partitioning coefficients of the elements, using the thermodynamic database (CALPHAD). We use this thermodynamic description to employ a quantitative phase-field model to assess the long-term stability of γ′ precipitates in IN740H utilizing GPU-based supercomputing architecture. The assessment helps us to enhance our understanding of the effect of the atomic diffusivity of Mo on coarsening kinetics of the γ′-precipitates in equivalent ternary Ni-Al-Mo superalloy. Investigation reveals that our phase-field model can accurately predict the experimentally observed coarsening kinetics in IN740H.
{"title":"Effect of molybdenum addition on precipitate coarsening kinetics in Inconel 740H: A phase-field study","authors":"Sourav Ghosh , Hemanth Kumar , Christian Brandl , Abhik N. Choudhury , Saswata Bhattacharyya , Rajdip Mukherjee","doi":"10.1016/j.intermet.2024.108513","DOIUrl":"10.1016/j.intermet.2024.108513","url":null,"abstract":"<div><div>Inconel 740H (IN740H) has emerged as an important candidate for the advanced ultra-supercritical (AUSC) steam turbines due to its superior microstructural stability and creep resistance under service conditions. In the present work, we have reparameterized a multicomponent Ni-based superalloy (IN740H) into an equivalent ternary Ni-Al-Mo superalloy, based on the partitioning coefficients of the elements, using the thermodynamic database (CALPHAD). We use this thermodynamic description to employ a quantitative phase-field model to assess the long-term stability of <em>γ</em>′ precipitates in IN740H utilizing GPU-based supercomputing architecture. The assessment helps us to enhance our understanding of the effect of the atomic diffusivity of Mo on coarsening kinetics of the <em>γ</em>′-precipitates in equivalent ternary Ni-Al-Mo superalloy. Investigation reveals that our phase-field model can accurately predict the experimentally observed coarsening kinetics in IN740H.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108513"},"PeriodicalIF":4.3,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433221","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 : 2024-10-12DOI: 10.1016/j.intermet.2024.108522
A.V. Maiorova, V.A. Bykov, P.V. Kotenkov
To reduce material costs, it is vital to develop reliable theoretical methods for predicting glass formation regions in multicomponent metal systems. We have developed a new model for predicting the compositions of quaternary amorphous metallic glasses and applied it to the Gd-Sc-Co-Al system. The proposed model parameters make it possible to predict the location of glass-forming compositions by finding the minimum of the PHSS parameter multiplication by the geometric coefficient , . The alloy with the composition Sc33Gd32Co19Al16 was successfully predicted and cast as a glass rod with a lateral size of 3 mm. According to the results of X-ray diffraction and thermal analysis, the sample Sc33Gd32Co19Al16 is an amorphous material with the lowest crystallinity index (4.3 %). The proposed approach can be used as a predictive model for determining glass-forming compositions in various quaternary metal systems.
{"title":"Development and testing of algorithms for predicting the glass-forming ability in the multicomponent Sc-Gd-Co-Al metallic alloys","authors":"A.V. Maiorova, V.A. Bykov, P.V. Kotenkov","doi":"10.1016/j.intermet.2024.108522","DOIUrl":"10.1016/j.intermet.2024.108522","url":null,"abstract":"<div><div>To reduce material costs, it is vital to develop reliable theoretical methods for predicting glass formation regions in multicomponent metal systems. We have developed a new model for predicting the compositions of quaternary amorphous metallic glasses and applied it to the Gd-Sc-Co-Al system. The proposed model parameters <span><math><mrow><msubsup><mi>Θ</mi><mrow><mi>i</mi><mo>−</mo><mi>j</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msubsup><mrow><mo>(</mo><msub><mi>x</mi><mi>i</mi></msub><mo>)</mo></mrow><mo>,</mo><msubsup><mi>Θ</mi><mrow><mi>i</mi><mo>−</mo><mi>j</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msubsup><mrow><mo>(</mo><msub><mi>x</mi><mi>j</mi></msub><mo>)</mo></mrow></mrow></math></span> make it possible to predict the location of glass-forming compositions by finding the minimum of the <em>P</em><sub>HSS</sub> parameter multiplication by the geometric coefficient <span><math><mrow><msub><mi>Γ</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><msub><mi>Γ</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></mrow></math></span>. The alloy with the composition Sc<sub>33</sub>Gd<sub>32</sub>Co<sub>19</sub>Al<sub>16</sub> was successfully predicted and cast as a glass rod with a lateral size of 3 mm. According to the results of X-ray diffraction and thermal analysis, the sample Sc<sub>33</sub>Gd<sub>32</sub>Co<sub>19</sub>Al<sub>16</sub> is an amorphous material with the lowest crystallinity index (4.3 %). The proposed approach can be used as a predictive model for determining glass-forming compositions in various quaternary metal systems.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108522"},"PeriodicalIF":4.3,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423472","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 : 2024-10-08DOI: 10.1016/j.intermet.2024.108521
Afagh Akbari, Reza Vafaei, Hossein Jamali, Ehsan Mohammad Sharifi
In this study, the microstructure, magnetic properties, and tensile behavior of high entropy alloys of FeCoNi(MnAl)x (x = 0–0.6, in molar ratios) were investigated after casting, cold rolling and annealing. X-ray diffractometry (XRD), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), and also tensile tests were used to evaluate phase formation, microstructure, magnetic behavior and tensile properties of the samples, respectively. The results showed that as the indices of x value increase to 0.6, crystallographic structures transform from FCC to FCC + BCC. This in turn decreased the magnetic saturation of FeCoNi(MnAl)0.6 from 151 to 36 emu/g. Increasing x to 0.6, also raised the values of Hc from 3 to 16 Oe. This behavior was also observed in annealed and cold rolled alloys. Annealing treatment also released the residual stresses and resulted in reduction of Hc values. However, the highest values of Hc was observed in cold rolled samples which ranged from 5 to 25 Oe. The tensile strength of cold rolled and annealed alloys for x values of 0, 0.2, and 0.4, were 510, 635, and 910 Mpa, respectively. Furthermore, the electrical resistance augmented monotonously with an increasing value of x. It is therefore concluded that cold rolled and annealed high entropy alloys of FeCoNi(AlMn)x can present a variety combinations of tensile, magnetic, and electrical behavior when compared to other soft magnetic materials.
本研究调查了 FeCoNi(MnAl)x（x = 0-0.6，摩尔比）高熵合金在铸造、冷轧和退火后的微观结构、磁性能和拉伸行为。分别使用了 X 射线衍射仪 (XRD)、场发射扫描电子显微镜 (FE-SEM)、振动样品磁力计 (VSM) 和拉伸试验来评估样品的相形成、微观结构、磁性行为和拉伸性能。结果表明，当 x 指数增加到 0.6 时，晶体结构从 FCC 转变为 FCC + BCC。这反过来又使铁钴镍锰铝 0.6 的磁饱和度从 151 降至 36 emu/g。将 x 增加到 0.6 时，Hc 值也从 3 Oe 增加到 16 Oe。在退火和冷轧合金中也观察到了这种行为。退火处理也释放了残余应力，导致 Hc 值降低。不过，冷轧样品的 Hc 值最高，在 5 到 25 Oe 之间。冷轧和退火合金在 x 值为 0、0.2 和 0.4 时的抗拉强度分别为 510、635 和 910 兆帕。因此可以得出结论，与其他软磁材料相比，冷轧和退火的高熵铁钴镍(铝锰)x 合金具有多种拉伸、磁性和电气性能。
{"title":"Effects of annealing and cold rolling on microstructural features, magnetic properties, tensile behavior and electrical resistance of FeCoNi(MnAl)x high entropy alloys","authors":"Afagh Akbari, Reza Vafaei, Hossein Jamali, Ehsan Mohammad Sharifi","doi":"10.1016/j.intermet.2024.108521","DOIUrl":"10.1016/j.intermet.2024.108521","url":null,"abstract":"<div><div>In this study, the microstructure, magnetic properties, and tensile behavior of high entropy alloys of FeCoNi(MnAl)<sub>x</sub> (x = 0–0.6, in molar ratios) were investigated after casting, cold rolling and annealing. X-ray diffractometry (XRD), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), and also tensile tests were used to evaluate phase formation, microstructure, magnetic behavior and tensile properties of the samples, respectively. The results showed that as the indices of x value increase to 0.6, crystallographic structures transform from FCC to FCC + BCC. This in turn decreased the magnetic saturation of FeCoNi(MnAl)<sub>0.6</sub> from 151 to 36 emu/g. Increasing x to 0.6, also raised the values of Hc from 3 to 16 Oe. This behavior was also observed in annealed and cold rolled alloys. Annealing treatment also released the residual stresses and resulted in reduction of Hc values. However, the highest values of Hc was observed in cold rolled samples which ranged from 5 to 25 Oe. The tensile strength of cold rolled and annealed alloys for x values of 0, 0.2, and 0.4, were 510, 635, and 910 Mpa, respectively. Furthermore, the electrical resistance augmented monotonously with an increasing value of x. It is therefore concluded that cold rolled and annealed high entropy alloys of FeCoNi(AlMn)x can present a variety combinations of tensile, magnetic, and electrical behavior when compared to other soft magnetic materials.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108521"},"PeriodicalIF":4.3,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423565","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 : 2024-10-07DOI: 10.1016/j.intermet.2024.108523
Shuai Zhang , Haoyu Zhang , Chuan Wang , Ge Zhou , Jun Cheng , Zhongshi Zhang , Xiaohu Wang , Lijia Chen
In this work, the vacuum arc-melting was used to prepare the Ti-10V-5Al-2.5Fe-0.1B alloy. Single-pass isothermal compression experiments were carried out on the alloy in the temperature range of 770–920 °C at strain rates of 0.0005–0.5 s−1. The BP model optimized by the bald eagle search algorithm (BES-BP), the BP model optimized by the sparrow search algorithm (SSA-BP), and the BP model optimized by the gray wolf optimization algorithm (GWO-BP) were developed for high-precision prediction of flow stress. The above models were compared by using the mean square correlation coefficient, root mean square error, and average absolute relative error between the predicted and experimental flow stress. The three prediction accuracy parameters have indicated that the BES-BP model has a higher accuracy for flow stress prediction at the known and the new process parameters. A hot processing map based on the dynamic materials model was developed by using the flow stress predicted in the framework of the BES-BP model, and EBSD analysis was performed as well. The results show that the degree of dynamic recrystallization increases with an increase in the power dissipation factor, and the formation of deformation bands is the main cause of instability. The minimum critical stress for inducing dynamic recrystallization of the alloy was found to be 13.13 MPa at 890 °C/0.0005 s−1. Moreover, the power dissipation factor increases with a decrease in critical stress. In addition, microstructure validation data reveal that the dynamic recrystallization model has a high accuracy for critical stress prediction, confirming that the critical stress increases with a decrease in the dynamic recrystallization fraction.
本研究采用真空电弧熔炼法制备了 Ti-10V-5Al-2.5Fe-0.1B 合金。在 770-920 °C 的温度范围内，以 0.0005-0.5 s-1 的应变速率对合金进行了单程等温压缩实验。针对流动应力的高精度预测，建立了秃鹰搜索算法优化的 BP 模型（BES-BP）、麻雀搜索算法优化的 BP 模型（SSA-BP）和灰狼优化算法优化的 BP 模型（GWO-BP）。采用均方相关系数、均方根误差和预测与实验流量应力的平均绝对相对误差对上述模型进行了比较。这三个预测精度参数表明，BES-BP 模型在已知工艺参数和新工艺参数下的流动应力预测精度更高。利用 BES-BP 模型框架下预测的流动应力，绘制了基于动态材料模型的热加工图，并进行了 EBSD 分析。结果表明，动态再结晶程度随功率耗散因子的增加而增加，变形带的形成是不稳定的主要原因。在 890 °C/0.0005 s-1 条件下，诱导合金动态再结晶的最小临界应力为 13.13 MPa。此外，功率耗散因数随着临界应力的降低而增加。此外，微观结构验证数据显示，动态再结晶模型对临界应力的预测具有很高的准确性，证实了临界应力随着动态再结晶分数的降低而增加。
{"title":"Prediction of flow and dynamic recrystallization behavior based on three machine learning methods for a novel duplex-phase titanium alloy","authors":"Shuai Zhang , Haoyu Zhang , Chuan Wang , Ge Zhou , Jun Cheng , Zhongshi Zhang , Xiaohu Wang , Lijia Chen","doi":"10.1016/j.intermet.2024.108523","DOIUrl":"10.1016/j.intermet.2024.108523","url":null,"abstract":"<div><div>In this work, the vacuum arc-melting was used to prepare the Ti-10V-5Al-2.5Fe-0.1B alloy. Single-pass isothermal compression experiments were carried out on the alloy in the temperature range of 770–920 °C at strain rates of 0.0005–0.5 s<sup>−1</sup>. The BP model optimized by the bald eagle search algorithm (BES-BP), the BP model optimized by the sparrow search algorithm (SSA-BP), and the BP model optimized by the gray wolf optimization algorithm (GWO-BP) were developed for high-precision prediction of flow stress. The above models were compared by using the mean square correlation coefficient, root mean square error, and average absolute relative error between the predicted and experimental flow stress. The three prediction accuracy parameters have indicated that the BES-BP model has a higher accuracy for flow stress prediction at the known and the new process parameters. A hot processing map based on the dynamic materials model was developed by using the flow stress predicted in the framework of the BES-BP model, and EBSD analysis was performed as well. The results show that the degree of dynamic recrystallization increases with an increase in the power dissipation factor, and the formation of deformation bands is the main cause of instability. The minimum critical stress for inducing dynamic recrystallization of the alloy was found to be 13.13 MPa at 890 °C/0.0005 s<sup>−1</sup>. Moreover, the power dissipation factor increases with a decrease in critical stress. In addition, microstructure validation data reveal that the dynamic recrystallization model has a high accuracy for critical stress prediction, confirming that the critical stress increases with a decrease in the dynamic recrystallization fraction.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108523"},"PeriodicalIF":4.3,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423515","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 : 2024-10-07DOI: 10.1016/j.intermet.2024.108502
Qiang Wan , Cai Lu , Yan Liu , Guodong Zhang , Jun Zhang , Bing Yang
High entropy alloys (HEAs) with nitriding process have been widely regarded as potential materials to manufacture machinery parts use in extremely environment such as high temperature, cryogenic temperatures, and corrosion conditions.
The multi-equal elements induced local chemical fluctuation (LCF) revealed significant effects in diffusion process which is the fundament for excellent thermal and chemical stability. However, the influence of LCF on the absorption stage of chemical surface process such as nitriding has remained uncertain so far, which greatly limited the application of chemical process in enhancing the surface hardness of HEAs. In this work, atomic-scale observations and first-principle calculations are combined to reveal that the presence of LCF determined the detailed effects of non-nitride forming element on nitrogen absorption and diffusion of nitride forming elements. In particular, Ni preferred locates closer with Cr while Co reveals equal space with Cr and Mn. This LCF promoted the absorption and diffusion of nitrogen in Cr lattice, arising from great decreased absorption energy and diffusion energy barrier (≈91.5 %). Thereby, the formation of nano CrN grains is enhanced via the co-contribution of accelerated absorption resulted from LCF and boundary diffusion via grain refinement. These findings provide profound understanding for HEA nitriding and promising strategy to improve the nitriding rate and hardness of HEAs.
采用氮化工艺的高熵合金（HEAs）已被广泛认为是制造高温、低温和腐蚀等极端环境下使用的机械零件的潜在材料。然而，迄今为止，LCF 对氮化等化学表面工艺吸收阶段的影响仍不确定，这极大地限制了化学工艺在提高 HEA 表面硬度方面的应用。在这项工作中，原子尺度观测和第一原理计算相结合，揭示了 LCF 的存在决定了非氮化物形成元素对氮化物形成元素的氮吸收和扩散的详细影响。特别是，镍与铬的位置更接近，而钴与铬和锰的空间相等。这种 LCF 促进了铬晶格中氮的吸收和扩散，因为吸收能和扩散能垒大大降低（≈91.5%）。因此，LCF 的加速吸收和晶粒细化的边界扩散共同促进了纳米 CrN 晶粒的形成。这些发现为 HEA 氮化提供了深刻的理解，并为提高 HEA 的氮化率和硬度提供了可行的策略。
{"title":"Local chemical fluctuation promoted formation of nano CrN to achieve superhardness in FeCoCrNiMn high entropy alloy","authors":"Qiang Wan , Cai Lu , Yan Liu , Guodong Zhang , Jun Zhang , Bing Yang","doi":"10.1016/j.intermet.2024.108502","DOIUrl":"10.1016/j.intermet.2024.108502","url":null,"abstract":"<div><div>High entropy alloys (HEAs) with nitriding process have been widely regarded as potential materials to manufacture machinery parts use in extremely environment such as high temperature, cryogenic temperatures, and corrosion conditions.</div><div>The multi-equal elements induced local chemical fluctuation (LCF) revealed significant effects in diffusion process which is the fundament for excellent thermal and chemical stability. However, the influence of LCF on the absorption stage of chemical surface process such as nitriding has remained uncertain so far, which greatly limited the application of chemical process in enhancing the surface hardness of HEAs. In this work, atomic-scale observations and first-principle calculations are combined to reveal that the presence of LCF determined the detailed effects of non-nitride forming element on nitrogen absorption and diffusion of nitride forming elements. In particular, Ni preferred locates closer with Cr while Co reveals equal space with Cr and Mn. This LCF promoted the absorption and diffusion of nitrogen in Cr lattice, arising from great decreased absorption energy and diffusion energy barrier (≈91.5 %). Thereby, the formation of nano CrN grains is enhanced via the co-contribution of accelerated absorption resulted from LCF and boundary diffusion via grain refinement. These findings provide profound understanding for HEA nitriding and promising strategy to improve the nitriding rate and hardness of HEAs.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108502"},"PeriodicalIF":4.3,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.intermet.2024.108516
Yao Huang , Yuqi Wang , Shan Yu , Hexin Zhang , Yihan Zhao , Chengzhi Zhao
A novel polycrystalline Ni3Al-based intermetallic alloy was prepared using the vacuum induction melting process. Subsequently, the alloy was subjected to the solution-treatment underwent two different aging processes: 870 °C for 24 h in air cooling, referred to as AT 1, and 1060 °C for 4 h in air cooling followed by 870 °C for 24 h in air cooling, referred to as AT 2. The effects of different aging processes on the microstructure and mechanical properties of the polycrystalline Ni3Al-based intermetallic alloys were analyzed. Results indicated the cubicity of the primary γ′ phase within the dendritic γ+γ′ structure of the AT 2 sample was significantly enhanced, yielding the best overall mechanical properties for the alloy. The percentage elongation increased from less than 3 % for the AT 1 sample to about 4.5 %, highlighting a notable enhancement in room temperature tensile plasticity. The creep rupture time at 1100 °C/30 MPa reached 113 h. The α-Cr particles in the As-cast and solid solution alloy gradually transformed into Cr23C6 during the aging process, exhibiting the orientation relationships of (020)Cr23C6||(010)γ' and [103]Cr23C6||[103]γ'. High-temperature aging treatments resulted in Cr23C6 particles that provided enhanced precipitation strengthening effects, thereby improving the creep rupture performance of the Ni3Al-based intermetallic alloys. Following high-temperature aging, a four-layer interface structure formed around the blocky γ′ matrix phase, which altered the alloy's fracture mechanism from a brittle intergranular fracture to a ductile transgranular fracture.
{"title":"Influence of aging heat treatment on microstructure and mechanical properties of a novel polycrystalline Ni3Al-based intermetallic alloy","authors":"Yao Huang , Yuqi Wang , Shan Yu , Hexin Zhang , Yihan Zhao , Chengzhi Zhao","doi":"10.1016/j.intermet.2024.108516","DOIUrl":"10.1016/j.intermet.2024.108516","url":null,"abstract":"<div><div>A novel polycrystalline Ni<sub>3</sub>Al-based intermetallic alloy was prepared using the vacuum induction melting process. Subsequently, the alloy was subjected to the solution-treatment underwent two different aging processes: 870 °C for 24 h in air cooling, referred to as AT 1, and 1060 °C for 4 h in air cooling followed by 870 °C for 24 h in air cooling, referred to as AT 2. The effects of different aging processes on the microstructure and mechanical properties of the polycrystalline Ni<sub>3</sub>Al-based intermetallic alloys were analyzed. Results indicated the cubicity of the primary γ′ phase within the dendritic γ+γ′ structure of the AT 2 sample was significantly enhanced, yielding the best overall mechanical properties for the alloy. The percentage elongation increased from less than 3 % for the AT 1 sample to about 4.5 %, highlighting a notable enhancement in room temperature tensile plasticity. The creep rupture time at 1100 °C/30 MPa reached 113 h. The α-Cr particles in the As-cast and solid solution alloy gradually transformed into Cr<sub>23</sub>C<sub>6</sub> during the aging process, exhibiting the orientation relationships of (020)<sub>Cr23C6</sub>||(010)<sub>γ'</sub> and [103]<sub>Cr23C6</sub>||[103]<sub>γ'</sub>. High-temperature aging treatments resulted in Cr<sub>23</sub>C<sub>6</sub> particles that provided enhanced precipitation strengthening effects, thereby improving the creep rupture performance of the Ni<sub>3</sub>Al-based intermetallic alloys. Following high-temperature aging, a four-layer interface structure formed around the blocky γ′ matrix phase, which altered the alloy's fracture mechanism from a brittle intergranular fracture to a ductile transgranular fracture.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108516"},"PeriodicalIF":4.3,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.intermet.2024.108515
Yixing Wan , Xiubing Liang , Yanhai Cheng , Yanan Liu , Pengfei He , Zhibin Zhang , Jinyong Mo
High-temperature structural alloys are urgently desired for refractory applications. In this work, we conceived a facile route to achieve an excellent combination of high-temperature strength and room-temperature ductility in a NbMoTaWHf refractory high-entropy alloy (RHEA). The idea is to break up the stable single body-centered cubic (BCC) phase in NbMoTaW RHEA to introduce the tiny secondary phase by alloying appropriate hafnium (Hf) that can stall and accumulate dislocations. The dual-BCC-phase structure and the dislocations for the NbMoTaWHf RHEA were characterized. The compressive yield strengths of the NbMoTaWHf RHEA at room temperature, 1200, 1600, and 1800 °C were 1730, 1088, 390, and 312 MPa, respectively. The alloy displayed plastic deformation behaviors and dual-BCC-phase structure stability after compressing at 1600 and 1800 °C. The superb high-temperature strength was mainly ascribed to the high softening temperature, second-phase strengthening, and solid-solution strengthening. This work provides a promising high-temperature structural material with improved room-temperature ductility and high strength at elevated temperatures and enriches the database of the NbMoTaW-based RHEAs.
{"title":"Superior high-temperature strength in a dual-BCC-phase NbMoTaWHf refractory high-entropy alloy","authors":"Yixing Wan , Xiubing Liang , Yanhai Cheng , Yanan Liu , Pengfei He , Zhibin Zhang , Jinyong Mo","doi":"10.1016/j.intermet.2024.108515","DOIUrl":"10.1016/j.intermet.2024.108515","url":null,"abstract":"<div><div>High-temperature structural alloys are urgently desired for refractory applications. In this work, we conceived a facile route to achieve an excellent combination of high-temperature strength and room-temperature ductility in a NbMoTaWHf refractory high-entropy alloy (RHEA). The idea is to break up the stable single body-centered cubic (BCC) phase in NbMoTaW RHEA to introduce the tiny secondary phase by alloying appropriate hafnium (Hf) that can stall and accumulate dislocations. The dual-BCC-phase structure and the dislocations for the NbMoTaWHf RHEA were characterized. The compressive yield strengths of the NbMoTaWHf RHEA at room temperature, 1200, 1600, and 1800 °C were 1730, 1088, 390, and 312 MPa, respectively. The alloy displayed plastic deformation behaviors and dual-BCC-phase structure stability after compressing at 1600 and 1800 °C. The superb high-temperature strength was mainly ascribed to the high softening temperature, second-phase strengthening, and solid-solution strengthening. This work provides a promising high-temperature structural material with improved room-temperature ductility and high strength at elevated temperatures and enriches the database of the NbMoTaW-based RHEAs.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"175 ","pages":"Article 108515"},"PeriodicalIF":4.3,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423514","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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