Pub Date : 2025-09-26DOI: 10.1016/j.mtla.2025.102563
Chengfeng Jiang , Jinwang Sun , Haiyan Chen , Lei Liu , Chuanchang Li , Dou Zhang
Dielectric capacitors are critical for energy storage applications, especially in pulsed power systems, owing to their ultrahigh power density and ultrafast charge/discharge capabilities. Among them, HfO₂-based thin films are particularly promising for micro-energy storage devices. In this work, double-layered Hf₀.₅Zr₀.₅O₂(3 nm)/ZrO₂(12 nm) (HZO3ZO12) films are deposited across a wide temperature range (80–225 °C) to systematically investigate their energy storage performance. A machine learning-assisted multi-objective optimization approach is employed to identify the optimal deposition temperature, revealing 128 °C as the ideal condition for maximizing energy storage properties. Further thickness optimization based on this deposition temperature is used to enhance the performance, achieving an excellent energy storage density of 113 J/cm³ at an applied electric field of 9.1 MV/cm. This study demonstrates a powerful strategy combining machine learning with experimental design to optimize dielectric capacitors, providing a roadmap for developing high-performance energy storage materials.
{"title":"Optimized energy storage performance in HZO3ZO12 thin films through modulation of deposition temperature and film thickness","authors":"Chengfeng Jiang , Jinwang Sun , Haiyan Chen , Lei Liu , Chuanchang Li , Dou Zhang","doi":"10.1016/j.mtla.2025.102563","DOIUrl":"10.1016/j.mtla.2025.102563","url":null,"abstract":"<div><div>Dielectric capacitors are critical for energy storage applications, especially in pulsed power systems, owing to their ultrahigh power density and ultrafast charge/discharge capabilities. Among them, HfO₂-based thin films are particularly promising for micro-energy storage devices. In this work, double-layered Hf₀.₅Zr₀.₅O₂(3 nm)/ZrO₂(12 nm) (HZO3ZO12) films are deposited across a wide temperature range (80–225 °C) to systematically investigate their energy storage performance. A machine learning-assisted multi-objective optimization approach is employed to identify the optimal deposition temperature, revealing 128 °C as the ideal condition for maximizing energy storage properties. Further thickness optimization based on this deposition temperature is used to enhance the performance, achieving an excellent energy storage density of 113 J/cm³ at an applied electric field of 9.1 MV/cm. This study demonstrates a powerful strategy combining machine learning with experimental design to optimize dielectric capacitors, providing a roadmap for developing high-performance energy storage materials.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102563"},"PeriodicalIF":2.9,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-25DOI: 10.1016/j.mtla.2025.102560
Aniruddha Das , Nicholas Derimow , Jared Tarr , Nik Hrabe , Jordan Weaver
Powder reuse is important to reduce the cost and improve the sustainability of laser powder bed fusion (PBF-LB) additive manufacturing. Several powder reuse strategies involve the blending of unused feedstock powder with used powder, which assume that the bulk properties of blends are sufficient knowledge for decision making. Here we consider how potential chemical heterogeneity within a blend may occur locally in the dispenser (e.g., a relatively high fraction of one component of the blend compared to the expected ratio). This becomes particularly important when the usage histories of the constituent powders in the blend have significant differences. A set of experiments was designed to introduce controlled heterogeneities in the dispenser and assess the effects on the spreading process and printed parts. Specific layer-wise heterogeneities were created by switching back and forth between powder feedstocks (IN718 and CoCrMo) during a build, as an analogous but more easily measurable situation compared to mixing and tracking reused powders of the same alloy. The Co concentration was spatially mapped parallel to the build height for lightly sintered powder capture capsules and solidified parts to determine how these heterogeneities manifest in the process before and after laser melting. The melting process in PBF-LB was determined to cause significant elemental redistribution as opposed to the initial powder spreading process, which had little contribution. In every case, the starting inhomogeneity diluted in intensity but increased in spatial size to more than twice the programmed layer thickness.
{"title":"Understanding the effects of metal powder feedstock heterogeneity on the laser powder bed fusion process","authors":"Aniruddha Das , Nicholas Derimow , Jared Tarr , Nik Hrabe , Jordan Weaver","doi":"10.1016/j.mtla.2025.102560","DOIUrl":"10.1016/j.mtla.2025.102560","url":null,"abstract":"<div><div>Powder reuse is important to reduce the cost and improve the sustainability of laser powder bed fusion (PBF-LB) additive manufacturing. Several powder reuse strategies involve the blending of unused feedstock powder with used powder, which assume that the bulk properties of blends are sufficient knowledge for decision making. Here we consider how potential chemical heterogeneity within a blend may occur locally in the dispenser (e.g., a relatively high fraction of one component of the blend compared to the expected ratio). This becomes particularly important when the usage histories of the constituent powders in the blend have significant differences. A set of experiments was designed to introduce controlled heterogeneities in the dispenser and assess the effects on the spreading process and printed parts. Specific layer-wise heterogeneities were created by switching back and forth between powder feedstocks (IN718 and CoCrMo) during a build, as an analogous but more easily measurable situation compared to mixing and tracking reused powders of the same alloy. The Co concentration was spatially mapped parallel to the build height for lightly sintered powder capture capsules and solidified parts to determine how these heterogeneities manifest in the process before and after laser melting. The melting process in PBF-LB was determined to cause significant elemental redistribution as opposed to the initial powder spreading process, which had little contribution. In every case, the starting inhomogeneity diluted in intensity but increased in spatial size to more than twice the programmed layer thickness.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102560"},"PeriodicalIF":2.9,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-24DOI: 10.1016/j.mtla.2025.102562
Zhan Yan , Jing Wang , Fu Wang , Haiyang Song , Yang Liu , Dichen Li , Jiantao Wu
DZ409 alloy is a new type of directional solidification nickel-based high-temperature alloy, which has excellent comprehensive performance. It can become a candidate alloy for the new generation of heavy-duty gas turbine blade materials that consider multiple properties. However, in the actual production process, shrinkage porosity often occurs in the castings, which seriously affects the mechanical properties. To investigate the effect of shrinkage porosity on the typical mechanical properties of DZ409 alloy in near service conditions (650 °C and 950 °C), Additionally, the tolerance limits of porosity for the basic mechanical properties of the DZ409 superalloy were determined, tensile experiments were designed on DZ409 specimens with different porosity amounts at 650 °C and 950 °C. The results indicate that the influence of micropores on tensile properties is non-monotonic. Furthermore, this non-monotonic influence law was verified through numerical simulation. This result indicates that when the pore content is within a limited range, its impact on the mechanical properties of directional castings is limited. The correlation between shrinkage porosity defects, mechanical properties, and microcracks has been studied, and the corresponding mechanisms have also been discussed.
{"title":"The effect of porosity content on the high-temperature mechanical properties of DZ409 superalloy","authors":"Zhan Yan , Jing Wang , Fu Wang , Haiyang Song , Yang Liu , Dichen Li , Jiantao Wu","doi":"10.1016/j.mtla.2025.102562","DOIUrl":"10.1016/j.mtla.2025.102562","url":null,"abstract":"<div><div>DZ409 alloy is a new type of directional solidification nickel-based high-temperature alloy, which has excellent comprehensive performance. It can become a candidate alloy for the new generation of heavy-duty gas turbine blade materials that consider multiple properties. However, in the actual production process, shrinkage porosity often occurs in the castings, which seriously affects the mechanical properties. To investigate the effect of shrinkage porosity on the typical mechanical properties of DZ409 alloy in near service conditions (650 °C and 950 °C), Additionally, the tolerance limits of porosity for the basic mechanical properties of the DZ409 superalloy were determined, tensile experiments were designed on DZ409 specimens with different porosity amounts at 650 °C and 950 °C. The results indicate that the influence of micropores on tensile properties is non-monotonic. Furthermore, this non-monotonic influence law was verified through numerical simulation. This result indicates that when the pore content is within a limited range, its impact on the mechanical properties of directional castings is limited. The correlation between shrinkage porosity defects, mechanical properties, and microcracks has been studied, and the corresponding mechanisms have also been discussed.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102562"},"PeriodicalIF":2.9,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The pursuit of safer and more efficient electrolytes is central to the development of next-generation lithium batteries. In this work, a hybrid gel polymer electrolyte (GPE) was engineered by combining poly(ethylene oxide) (PEO) with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) and functionalized with graphene oxide (GO). The introduction of GO disrupted PEO crystallinity and enhanced segmental motion, yielding a fourfold increase in ionic conductivity compared to the pristine polymer matrix. At an optimal loading of 1.5 wt%, the GPE achieved 1.29 × 10⁻⁴ S·cm⁻¹ while maintaining structural integrity and interfacial stability. To further boost performance, a thin lithium coating was deposited on the GPE surface, promoting uniform ion flux and reducing interfacial resistance. When paired with ZnO–Zn₃N₂ thin-film anodes, the modified GPE delivered stable cycling with capacities of 350–370 mAh g⁻¹ and 264 mAh g⁻¹ retained after 200 cycles at 0.1C, alongside Coulombic efficiencies exceeding 97 %. These findings highlight a synergistic design strategy that combines nanofiller engineering with interfacial modification to advance solid-state and gel-based lithium batteries.
追求更安全、更高效的电解质是下一代锂电池发展的核心。在这项工作中，通过将聚（环氧乙烷）（PEO）与聚（偏氟乙烯-共六氟丙烯）（pvdf -共hfp）结合并与氧化石墨烯（GO）功能化，设计了一种混合凝胶聚合物电解质（GPE）。氧化石墨烯的引入破坏了PEO的结晶度，增强了片段运动，与原始聚合物基体相比，离子电导率提高了四倍。在1.5 wt%的最佳载荷下，GPE在保持结构完整性和界面稳定性的同时达到1.29 × 10⁻⁴S·cm⁻¹。为了进一步提高性能，在GPE表面沉积了一层薄锂涂层，促进了均匀的离子通量并降低了界面阻力。当与ZnO-Zn₃N₂薄膜阳极配合使用时，改性GPE提供了稳定的循环能力，在0.1C下循环200次后，容量为350-370 mAh g⁻¹，并保持264 mAh g⁻¹，库仑效率超过97%。这些发现强调了一种协同设计策略，将纳米填料工程与界面改性相结合，以推进固态和凝胶基锂电池的发展。
{"title":"Asymmetric Li-Coated PEO–PVDF-co-HFP Membrane with Graphene Oxide as Next-Generation Gel Polymer Electrolytes for Li-Ion Batteries","authors":"Yer-Targyn Tleukenov , Yessimzhan Raiymbekov , Mukagali Yegamkulov , Arailym Nurpeissova , Zhumabay Bakenov , Aliya Mukanova","doi":"10.1016/j.mtla.2025.102559","DOIUrl":"10.1016/j.mtla.2025.102559","url":null,"abstract":"<div><div>The pursuit of safer and more efficient electrolytes is central to the development of next-generation lithium batteries. In this work, a hybrid gel polymer electrolyte (GPE) was engineered by combining poly(ethylene oxide) (PEO) with poly(vinylidene fluoride-<em>co</em>-hexafluoropropylene) (PVDF-<em>co</em>-HFP) and functionalized with graphene oxide (GO). The introduction of GO disrupted PEO crystallinity and enhanced segmental motion, yielding a fourfold increase in ionic conductivity compared to the pristine polymer matrix. At an optimal loading of 1.5 wt%, the GPE achieved 1.29 × 10⁻⁴ S·cm⁻¹ while maintaining structural integrity and interfacial stability. To further boost performance, a thin lithium coating was deposited on the GPE surface, promoting uniform ion flux and reducing interfacial resistance. When paired with ZnO–Zn₃N₂ thin-film anodes, the modified GPE delivered stable cycling with capacities of 350–370 mAh g⁻¹ and 264 mAh g⁻¹ retained after 200 cycles at 0.1C, alongside Coulombic efficiencies exceeding 97 %. These findings highlight a synergistic design strategy that combines nanofiller engineering with interfacial modification to advance solid-state and gel-based lithium batteries.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102559"},"PeriodicalIF":2.9,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-23DOI: 10.1016/j.mtla.2025.102558
Yuanyuan Zuo , Shuai Yuan , Xuefeng Han , Xin Tian , Zhaoshuai Gao , Lingfeng Xu , Hengtao Ge , Peizhi Zhao , Hongfu Jiang , Jinrong Wang , Junfu Ni , Yu Gao , Jianwei Cao , Zhongshi Lou , Wei Sun , Deren Yang
Large-diameter Floating-zone (FZ) silicon, particularly 8-inch crystals, is essential for high-voltage devices like insulated gate bipolar transistors (IGBTs) and fast recovery diodes (FRDs), yet its production is hindered by low crystal growth yield due to ridge breakage defects. This study investigates inclusion-induced ridge breakage mechanisms in mass-produced 8-inch FZ silicon, using 8-inch (100) and 5-inch (111) crystals, with the latter employed to study bulk defect propagation. Through scanning electron microscopy, energy-dispersive spectroscopy, and mechanochemical polishing, we identified two mechanisms: surface-origin carbon inclusions, likely silicon carbide particles from graphite wear at the initial heating stage, induce twin formation, while bulk-origin microcrystalline silicon inclusions trigger dislocations and cracks. Numerical simulations revealed that central and edge high-stress zones amplify inclusion effects, with stress scaling linearly with diameter, exacerbating breakage in 8-inch crystals. A stress-inclusion interaction model explains how inclusions narrow the tolerable stress window. These findings advocate optimizing preform rod preparation and heating processes to minimize inclusions, enhancing yield for 8-inch FZ silicon in high-performance electronics.
{"title":"Inclusion-related ridge breakage in large-diameter floating-zone silicon","authors":"Yuanyuan Zuo , Shuai Yuan , Xuefeng Han , Xin Tian , Zhaoshuai Gao , Lingfeng Xu , Hengtao Ge , Peizhi Zhao , Hongfu Jiang , Jinrong Wang , Junfu Ni , Yu Gao , Jianwei Cao , Zhongshi Lou , Wei Sun , Deren Yang","doi":"10.1016/j.mtla.2025.102558","DOIUrl":"10.1016/j.mtla.2025.102558","url":null,"abstract":"<div><div>Large-diameter Floating-zone (FZ) silicon, particularly 8-inch crystals, is essential for high-voltage devices like insulated gate bipolar transistors (IGBTs) and fast recovery diodes (FRDs), yet its production is hindered by low crystal growth yield due to ridge breakage defects. This study investigates inclusion-induced ridge breakage mechanisms in mass-produced 8-inch FZ silicon, using 8-inch (100) and 5-inch (111) crystals, with the latter employed to study bulk defect propagation. Through scanning electron microscopy, energy-dispersive spectroscopy, and mechanochemical polishing, we identified two mechanisms: surface-origin carbon inclusions, likely silicon carbide particles from graphite wear at the initial heating stage, induce twin formation, while bulk-origin microcrystalline silicon inclusions trigger dislocations and cracks. Numerical simulations revealed that central and edge high-stress zones amplify inclusion effects, with stress scaling linearly with diameter, exacerbating breakage in 8-inch crystals. A stress-inclusion interaction model explains how inclusions narrow the tolerable stress window. These findings advocate optimizing preform rod preparation and heating processes to minimize inclusions, enhancing yield for 8-inch FZ silicon in high-performance electronics.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102558"},"PeriodicalIF":2.9,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elastic energy plays a critical role in determining phase stability in compositionally complex alloys. However, quantifying elastic contributions in multi-component systems and incorporating them into phase diagram construction remain challenging. In this study, we present a generalized elastic energy formalism tailored for multi-component alloys, which can be directly and efficiently integrated with CALPHAD thermodynamic databases and existing frameworks such as Thermo-Calc (Andersson et al., 2002), Pandat (Cao et al., 2009) or FactSage (Bale et al., 2016). This elasticity formalism can also be introduced as a post-processing layer in open-source software such as pyCALPHAD (Otis and Liu, 2017) and Kawin (Ury et al., 2023) , enabling elastic assessments in multi-component systems.
We apply our framework for constructing the phase diagram of quinary Fe–Mn–Ni–Co–Cu alloy system, utilizing convex hull and Hessian matrix under elastic considerations. Our results reveal that incorporating elastic energy leads to an expansion of both the spinodal region and the miscibility gap. These are governed by the intricate interplay of chemical and elastic driving forces: We found that Mn and Ni contribute strongly to chemical stabilization, while Cu and Co tend to destabilize the alloy, especially at low Mn concentrations. The stabilizing effect of Fe is also pronounced in Mn-deficient regions. Acting as a destabilizing factor, the elastic energy is primarily driven by the presence of Mn, underscoring its multifaceted role in thermodynamic stability. In Mn-rich compositions, Cu markedly reduces the elastic energy contribution. Combined with CALPHAD infrastructures, the current framework offers a practical pathway to improve the predictive accuracy of phase stability and transformations in complex multi-component alloys.
在复杂合金中，弹性能是决定相稳定性的关键因素。然而，量化多组分系统中的弹性贡献并将其纳入相图构建仍然具有挑战性。在本研究中，我们提出了一种针对多组分合金的广义弹性能量形式，该形式可以直接有效地与CALPHAD热力学数据库和现有框架(如thermal - calc （Andersson等人，2002）、Pandat （Cao等人，2009）或FactSage （Bale等人，2016）集成。这种弹性形式也可以作为后处理层引入开源软件，如pyCALPHAD （Otis and Liu, 2017）和Kawin (Ury et al., 2023)，从而可以在多组件系统中进行弹性评估。在弹性条件下，利用凸包和Hessian矩阵，应用我们的框架构造了Fe-Mn-Ni-Co-Cu合金体系的相图。我们的研究结果表明，加入弹性能会导致旋多区和混相间隙的扩大。这些是由化学和弹性驱动力的复杂相互作用所控制的：我们发现Mn和Ni对化学稳定有很强的贡献，而Cu和Co倾向于破坏合金的稳定，特别是在低Mn浓度下。铁的稳定作用在缺锰地区也很明显。作为一个不稳定因素，弹性能主要是由Mn的存在驱动的，强调了它在热力学稳定性中的多方面作用。在富锰组分中，Cu显著降低了弹性能的贡献。结合CALPHAD基础结构，目前的框架为提高复杂多组分合金相稳定性和相变的预测精度提供了一条实用的途径。
{"title":"Incorporating elasticity into the thermodynamics and phase diagrams of multi-component systems","authors":"Niklas Marschall , Jegatheesan Murugan , Reza Darvishi Kamachali","doi":"10.1016/j.mtla.2025.102546","DOIUrl":"10.1016/j.mtla.2025.102546","url":null,"abstract":"<div><div>Elastic energy plays a critical role in determining phase stability in compositionally complex alloys. However, quantifying elastic contributions in multi-component systems and incorporating them into phase diagram construction remain challenging. In this study, we present a generalized elastic energy formalism tailored for multi-component alloys, which can be directly and efficiently integrated with CALPHAD thermodynamic databases and existing frameworks such as Thermo-Calc (Andersson et al., 2002), Pandat (Cao et al., 2009) or FactSage (Bale et al., 2016). This elasticity formalism can also be introduced as a post-processing layer in open-source software such as pyCALPHAD (Otis and Liu, 2017) and Kawin (Ury et al., 2023) , enabling elastic assessments in multi-component systems.</div><div>We apply our framework for constructing the phase diagram of quinary Fe–Mn–Ni–Co–Cu alloy system, utilizing convex hull and Hessian matrix under elastic considerations. Our results reveal that incorporating elastic energy leads to an expansion of both the spinodal region and the miscibility gap. These are governed by the intricate interplay of chemical and elastic driving forces: We found that Mn and Ni contribute strongly to chemical stabilization, while Cu and Co tend to destabilize the alloy, especially at low Mn concentrations. The stabilizing effect of Fe is also pronounced in Mn-deficient regions. Acting as a destabilizing factor, the elastic energy is primarily driven by the presence of Mn, underscoring its multifaceted role in thermodynamic stability. In Mn-rich compositions, Cu markedly reduces the elastic energy contribution. Combined with CALPHAD infrastructures, the current framework offers a practical pathway to improve the predictive accuracy of phase stability and transformations in complex multi-component alloys.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102546"},"PeriodicalIF":2.9,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-20DOI: 10.1016/j.mtla.2025.102557
S. Gholizadeh , S Chung Kim Yuen , S.L. George
Blast loading generates intense shock waves that produce inhomogeneous strain, leading to severe plastic deformation or failure through mechanisms such as twinning, dislocation multiplication, and grain morphology evolution. Understanding the influence of crystal structure on mechanical and microstructural response under such conditions is critical for designing materials for protective and structural applications. This study investigates the behavior of body-centered cubic (BCC) Ferritic Stainless Steel (FSS 430) under localized blast loads and compares it with face-centered cubic (FCC) Austenitic Stainless Steel (ASS 316L), building on our previous work under similar loading conditions. Square test plates, 2mm thick, with circular areas of 106 mm in diameter, were exposed to localized blast loads. Post-blast evaluation was examined using micro-tensile testing to assess changes in mechanical properties, while electron backscatter diffraction (EBSD) was used to interrogate strain localization, twinning activity, and dislocation storage. The results revealed distinct crystal-structure-dependent responses. FSS 430 (BCC) exhibited highly localized strain accumulation, characterized by the formation of very low-angle grain boundaries (VLAGBs) and activation of blast-induced twinning on the {332}<113> system. In contrast, ASS 316L (FCC) showed more uniform strain distribution, dominated by annealing twins on {111}<112> and close-packed slip on {111}<110>, with non-octahedral slip on {100}<110> as a secondary mechanism. The findings also highlighted while both structures exhibited similar deflection and strain distribution, the superior ability of FCC alloys to distribute strain uniformly and better energy absorption, while BCC alloys tended to concentrate deformation in isolated regions, increasing susceptibility to localized failure. These findings provide valuable insight into the role of crystal structure in blast resilience and can inform the selection and development of materials with improved blast protection capabilities.
{"title":"Comparative analysis of microstructural and mechanical properties in BCC and FCC metals subjected to localized blast loads","authors":"S. Gholizadeh , S Chung Kim Yuen , S.L. George","doi":"10.1016/j.mtla.2025.102557","DOIUrl":"10.1016/j.mtla.2025.102557","url":null,"abstract":"<div><div>Blast loading generates intense shock waves that produce inhomogeneous strain, leading to severe plastic deformation or failure through mechanisms such as twinning, dislocation multiplication, and grain morphology evolution. Understanding the influence of crystal structure on mechanical and microstructural response under such conditions is critical for designing materials for protective and structural applications. This study investigates the behavior of body-centered cubic (BCC) Ferritic Stainless Steel (FSS 430) under localized blast loads and compares it with face-centered cubic (FCC) Austenitic Stainless Steel (ASS 316L), building on our previous work under similar loading conditions. Square test plates, 2mm thick, with circular areas of 106 mm in diameter, were exposed to localized blast loads. Post-blast evaluation was examined using micro-tensile testing to assess changes in mechanical properties, while electron backscatter diffraction (EBSD) was used to interrogate strain localization, twinning activity, and dislocation storage. The results revealed distinct crystal-structure-dependent responses. FSS 430 (BCC) exhibited highly localized strain accumulation, characterized by the formation of very low-angle grain boundaries (VLAGBs) and activation of blast-induced twinning on the {332}<113> system. In contrast, ASS 316L (FCC) showed more uniform strain distribution, dominated by annealing twins on {111}<112> and close-packed slip on {111}<110>, with non-octahedral slip on {100}<110> as a secondary mechanism. The findings also highlighted while both structures exhibited similar deflection and strain distribution, the superior ability of FCC alloys to distribute strain uniformly and better energy absorption, while BCC alloys tended to concentrate deformation in isolated regions, increasing susceptibility to localized failure. These findings provide valuable insight into the role of crystal structure in blast resilience and can inform the selection and development of materials with improved blast protection capabilities.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102557"},"PeriodicalIF":2.9,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145332739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-17DOI: 10.1016/j.mtla.2025.102556
Aritra Sarkar , Simen U. Tråstadkjølen , Håvard Wilson , Jon Holmestad , Bård Nyhus , Nima Razavi
The present study investigates the synergistic influence of fatigue and corrosion damage in a simulated recycled 6082 Al-alloy with high content of trace elements like Fe, Cu and Zn through carrying out high cycle fatigue (HCF) tests after prior accelerated intergranular corrosion at different durations viz. 1, 4, 12 and 24 h- in as-extruded and glass-bead blasted condition. Maximum corrosion depth is found to show an increasing trend for all corrosion durations barring between 4 and 12 h. On the contrary, fatigue life is found to reduce with consecutive levels of increasing corrosion duration, but the reduction is significant only at shorter corrosion duration like 1 or 4 h. This depicts an inverse relationship between fatigue life and corrosion depth, indicating the possibility of a critical corrosion depth beyond which corrosion attack does not affect the fatigue life significantly. Detailed fractographic investigation revealed that this phenomenon is attributed to significant curtailing of the crack-initiation phase even at smaller corrosion durations, on account of extensive intergranular corrosion emanating from corrosion pits in the surface grains. Although glass-bead blasting leads to significant improvement in fatigue life in controlled condition, the extent of such improvement is significantly curtailed in pre-corroded condition owing to the presence of intergranular corrosion extending to the interior grains, which offsets to a great extent the effect of compressive residual stresses present in the surface layer.
{"title":"Influence of prior corrosion on fatigue behaviour in a simulated recycled 6082 Al-alloy","authors":"Aritra Sarkar , Simen U. Tråstadkjølen , Håvard Wilson , Jon Holmestad , Bård Nyhus , Nima Razavi","doi":"10.1016/j.mtla.2025.102556","DOIUrl":"10.1016/j.mtla.2025.102556","url":null,"abstract":"<div><div>The present study investigates the synergistic influence of fatigue and corrosion damage in a simulated recycled 6082 Al-alloy with high content of trace elements like Fe, Cu and Zn through carrying out high cycle fatigue (HCF) tests after prior accelerated intergranular corrosion at different durations viz. 1, 4, 12 and 24 h- in as-extruded and glass-bead blasted condition. Maximum corrosion depth is found to show an increasing trend for all corrosion durations barring between 4 and 12 h. On the contrary, fatigue life is found to reduce with consecutive levels of increasing corrosion duration, but the reduction is significant only at shorter corrosion duration like 1 or 4 h. This depicts an inverse relationship between fatigue life and corrosion depth, indicating the possibility of a critical corrosion depth beyond which corrosion attack does not affect the fatigue life significantly. Detailed fractographic investigation revealed that this phenomenon is attributed to significant curtailing of the crack-initiation phase even at smaller corrosion durations, on account of extensive intergranular corrosion emanating from corrosion pits in the surface grains. Although glass-bead blasting leads to significant improvement in fatigue life in controlled condition, the extent of such improvement is significantly curtailed in pre-corroded condition owing to the presence of intergranular corrosion extending to the interior grains, which offsets to a great extent the effect of compressive residual stresses present in the surface layer.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102556"},"PeriodicalIF":2.9,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-17DOI: 10.1016/j.mtla.2025.102554
Sakshi Bajpai , Xin Wang , Bijun Xie , Hangman Chen , Jize Zhang , Calvin Belcher , Benjamin MacDonald , Julia Ivanisenko , Yu Zhong , Penghui Cao , Enrique J. Lavernia , Diran Apelian
Complex, concentrated alloys (CCAs) are composed of multiple principal elements in significant proportions and have attracted substantial interest due to their distinctive properties. It was initially thought that CCAs formed primarily as single-phase structures; however, subsequent research has revealed that CCAs may undergo phase decomposition when subjected to intermediate temperatures over extended durations. This study investigates the phase stability of equiatomic CoCrNi alloy, commonly recognized as a single-phase face-centered cubic (FCC) material. The alloy was subjected to severe plastic deformation, resulting in a high density of grain boundaries and deformation-induced structures. Guided by the calculation of phase diagrams (CALPHAD) predictions, prolonged annealing at a selected temperature was conducted to evaluate its phase stability. Microstructural characterization from the micro- to atomic-scale revealed that the FCC matrix undergoes structural decomposition into an HCP phase, accompanied by elemental partitioning within this phase. Transmission electron microscopy confirmed the presence of the HCP phase, while high-throughput CALPHAD and hybrid Monte Carlo/Molecular Dynamics simulations provided mechanistic insights into its formation. The emergence of this HCP phase, and the associated redistribution of elements, explains the observed differences in phase constitution compared to previously studied alloys. These findings highlight the critical role of processing-dependent phase evolution and elemental partitioning in dictating the performance of complex concentrated alloys (CCAs), thereby influencing their mechanical properties and long-term reliability in demanding applications.
{"title":"Phase decomposition in the equiatomic CoCrNi alloy","authors":"Sakshi Bajpai , Xin Wang , Bijun Xie , Hangman Chen , Jize Zhang , Calvin Belcher , Benjamin MacDonald , Julia Ivanisenko , Yu Zhong , Penghui Cao , Enrique J. Lavernia , Diran Apelian","doi":"10.1016/j.mtla.2025.102554","DOIUrl":"10.1016/j.mtla.2025.102554","url":null,"abstract":"<div><div>Complex, concentrated alloys (CCAs) are composed of multiple principal elements in significant proportions and have attracted substantial interest due to their distinctive properties. It was initially thought that CCAs formed primarily as single-phase structures; however, subsequent research has revealed that CCAs may undergo phase decomposition when subjected to intermediate temperatures over extended durations. This study investigates the phase stability of equiatomic CoCrNi alloy, commonly recognized as a single-phase face-centered cubic (FCC) material. The alloy was subjected to severe plastic deformation, resulting in a high density of grain boundaries and deformation-induced structures. Guided by the calculation of phase diagrams (CALPHAD) predictions, prolonged annealing at a selected temperature was conducted to evaluate its phase stability. Microstructural characterization from the micro- to atomic-scale revealed that the FCC matrix undergoes structural decomposition into an HCP phase, accompanied by elemental partitioning within this phase. Transmission electron microscopy confirmed the presence of the HCP phase, while high-throughput CALPHAD and hybrid Monte Carlo/Molecular Dynamics simulations provided mechanistic insights into its formation. The emergence of this HCP phase, and the associated redistribution of elements, explains the observed differences in phase constitution compared to previously studied alloys. These findings highlight the critical role of processing-dependent phase evolution and elemental partitioning in dictating the performance of complex concentrated alloys (CCAs), thereby influencing their mechanical properties and long-term reliability in demanding applications.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102554"},"PeriodicalIF":2.9,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-16DOI: 10.1016/j.mtla.2025.102547
E.C. Galliopoulou , S. He , G.T. Martinez , P.J. Thomas , L. Coghlan , H. Shang , C. Jones , M. Zimina , J. Siefert , J.D. Parker , G.M. Hughes , N. Grilli , A. Cocks , T.L. Martin
The majority of premature failures in Grade 91 steel components used in high-temperature applications, such as power plants, are attributed to creep cavity nucleation. This study examined creep cavity nucleation in ferritic P91 ex-service material during its early formation stages through interrupted creep tests at 4% and 10% strain, as well as in later stages by analysing a failed creep-tested specimen with 35.6% strain at failure. While cavity growth under high-temperature exposure did not require applied stress, cavity interlinkage was more pronounced in high-stress regions. It was found that manganese sulfide (MnS) inclusions were highly prone to damage and were responsible for the nucleation of the first cavities during early creep life stages. This process was facilitated by the presence of M23C6 carbides and Laves phase located at the interface between the MnS inclusions and the ferrite matrix. Grain boundary misorientation was highly associated with cavitation with grain boundaries of misorientations being the predominant type in the ferritic microstructure and, consequently, the most frequently cavitating. Although less frequent in the microstructure, lower-angle GBs with misorientations exhibited the highest cavitation ratios. Localized deformation was found to be strongly correlated with cavitation, whereas the Schmid factor did not exhibit a statistically significant link to damage. A dense dislocation structure, observed using TEM and SEM imaging at early creep life stages, was significantly reduced at the failure stage, likely due to dislocation relief during cavity formation and crack propagation.
{"title":"Investigation of creep cavitation mechanisms in ferritic Grade 91 steel","authors":"E.C. Galliopoulou , S. He , G.T. Martinez , P.J. Thomas , L. Coghlan , H. Shang , C. Jones , M. Zimina , J. Siefert , J.D. Parker , G.M. Hughes , N. Grilli , A. Cocks , T.L. Martin","doi":"10.1016/j.mtla.2025.102547","DOIUrl":"10.1016/j.mtla.2025.102547","url":null,"abstract":"<div><div>The majority of premature failures in Grade 91 steel components used in high-temperature applications, such as power plants, are attributed to creep cavity nucleation. This study examined creep cavity nucleation in ferritic P91 ex-service material during its early formation stages through interrupted creep tests at 4% and 10% strain, as well as in later stages by analysing a failed creep-tested specimen with 35.6% strain at failure. While cavity growth under high-temperature exposure did not require applied stress, cavity interlinkage was more pronounced in high-stress regions. It was found that manganese sulfide (MnS) inclusions were highly prone to damage and were responsible for the nucleation of the first cavities during early creep life stages. This process was facilitated by the presence of M<sub>23</sub>C<sub>6</sub> carbides and Laves phase located at the interface between the MnS inclusions and the ferrite matrix. Grain boundary misorientation was highly associated with cavitation with grain boundaries of misorientations <span><math><mrow><mn>45</mn><mo>−</mo><mn>5</mn><msup><mrow><mn>5</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> being the predominant type in the ferritic microstructure and, consequently, the most frequently cavitating. Although less frequent in the microstructure, lower-angle GBs with misorientations <span><math><mrow><mo><</mo><mn>15</mn><mo>−</mo><mn>2</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> exhibited the highest cavitation ratios. Localized deformation was found to be strongly correlated with cavitation, whereas the Schmid factor did not exhibit a statistically significant link to damage. A dense dislocation structure, observed using TEM and SEM imaging at early creep life stages, was significantly reduced at the failure stage, likely due to dislocation relief during cavity formation and crack propagation.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102547"},"PeriodicalIF":2.9,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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