The effects of P on the creep deformation behavior for a Ni-Fe-Cr based alloy were studied by interrupted creep test. The results show that the P-doping can suppress the growth of M23C6, but has no effect on coarsening rate of γ’ during creep deformation. And the addition of P can not only retard the pile-up of dislocation near grain boundary, but also increase the stress concentration limit of grain boundary. First of all, P can retard the movement of grain boundary and dislocation by increasing grain boundary cohesion. Therefore, the grain rotation to 〈111〉 orientation and the appearance of hard grains are inhibited, which decreases the geometrically necessary dislocation density near the grain boundary and delays the creep damage process during creep deformation. Then, the granular M23C6 in the P-containing alloy can improve the deformation coordination between the adjacent grains, which increases the fraction of hard grains with <111> orientation after creep failure fracture. Hence, the addition of P increases the stress concentration limit of grain boundary and extends the creep damage process. Based on the two effects of P mentioned above, phosphorus microalloying can transform the creep damage type from microcracks to creep cavities and increase the creep strength and ductility for the Ni-Fe-Cr based alloy.
{"title":"Creep deformation behavior of a Ni-Fe-Cr based alloy: Key influences of phosphorus microalloying","authors":"Yunsheng Wu , Xiangxiang Zhang , Lei Jiang , Fanwei Zeng , Changshuai Wang , Yongan Guo , Jieshan Hou , Xianjun Guan , Lanzhang Zhou","doi":"10.1016/j.matchar.2024.114702","DOIUrl":"10.1016/j.matchar.2024.114702","url":null,"abstract":"<div><div>The effects of P on the creep deformation behavior for a Ni-Fe-Cr based alloy were studied by interrupted creep test. The results show that the P-doping can suppress the growth of M<sub>23</sub>C<sub>6</sub>, but has no effect on coarsening rate of γ’ during creep deformation. And the addition of P can not only retard the pile-up of dislocation near grain boundary, but also increase the stress concentration limit of grain boundary. First of all, P can retard the movement of grain boundary and dislocation by increasing grain boundary cohesion. Therefore, the grain rotation to 〈111〉 orientation and the appearance of hard grains are inhibited, which decreases the geometrically necessary dislocation density near the grain boundary and delays the creep damage process during creep deformation. Then, the granular M<sub>23</sub>C<sub>6</sub> in the P-containing alloy can improve the deformation coordination between the adjacent grains, which increases the fraction of hard grains with <111> orientation after creep failure fracture. Hence, the addition of P increases the stress concentration limit of grain boundary and extends the creep damage process. Based on the two effects of P mentioned above, phosphorus microalloying can transform the creep damage type from microcracks to creep cavities and increase the creep strength and ductility for the Ni-Fe-Cr based alloy.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114702"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130695","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 : 2025-02-01DOI: 10.1016/j.matchar.2024.114663
Rui Li , Chuanlong Yang , Mengtian Liang , Yongjin Chen , Huaqing Yi , Jinpeng Zhang , Yi Yang
A novel program for space group determination based on the real space method which is simple, exact, and enables more space groups to be distinguished is presented. The program employs model-based estimation, which enables the analysis of a vast field of HAADF images to obtain atomic positions and amplitudes with remarkable precision. It applies the Niggli reduced cell method to determine lattice parameters, calculates the two-dimensional (2D) space group using the information derived from lattice parameters, atomic positions and amplitudes, and then to uniquely identify a three-dimensional (3D) space group by this information. This article presents several instances of 2D plane group identification and a number of examples of space group determination based on both simulated and experimental HAADF images. AutoSGD, a user-friendly program, has been developed to facilitate the space group determination for researchers.
{"title":"Automatic determination of crystal space groups based on the real space method","authors":"Rui Li , Chuanlong Yang , Mengtian Liang , Yongjin Chen , Huaqing Yi , Jinpeng Zhang , Yi Yang","doi":"10.1016/j.matchar.2024.114663","DOIUrl":"10.1016/j.matchar.2024.114663","url":null,"abstract":"<div><div>A novel program for space group determination based on the real space method which is simple, exact, and enables more space groups to be distinguished is presented. The program employs model-based estimation, which enables the analysis of a vast field of HAADF images to obtain atomic positions and amplitudes with remarkable precision. It applies the Niggli reduced cell method to determine lattice parameters, calculates the two-dimensional (2D) space group using the information derived from lattice parameters, atomic positions and amplitudes, and then to uniquely identify a three-dimensional (3D) space group by this information. This article presents several instances of 2D plane group identification and a number of examples of space group determination based on both simulated and experimental HAADF images. AutoSGD, a user-friendly program, has been developed to facilitate the space group determination for researchers.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114663"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130686","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}
Phase and grain boundaries can effectively strengthen dual-phase high-entropy alloys (HEAs), but as service temperature increases, they could also become sources of weakness and damage. In this work, microstructures with different phase and grain boundary densities were designed in a hypoeutectic HEA to compare their different effects on cracking behavior at elevated temperatures. The tensile ductility significantly increased by reducing the intergranular fracture with decreased grain boundary density. The analyses revealed that the grain boundary was prone to crack at the triple junctions and served as the crack propagation path. Differently, although the phase boundary also cracked preferentially, it was highly resistant to crack propagation by its serrated morphology and defects emission at the crack tip. The directionally solidified sample further proved the benefit by suppressing the intergranular cracking, achieving a higher yield strength of ∼701 MPa and considerable tensile ductility of ∼31.5 % at 800 °C. These findings create a microstructural optimization pathway based on the cracking mechanisms, aiming to produce high-performance dual-phase HEAs for application in a wide temperature range.
{"title":"Revealing cracking behavior of phase and grain boundaries in dual-phase high-entropy alloy at elevated temperatures","authors":"Linxiang Liu, Qingfeng Wu, Jiaxi Zhu, Xiaoyu Bai, Yuhao Jia, Feng He, Junjie Li, Jincheng Wang, Zhijun Wang","doi":"10.1016/j.matchar.2024.114703","DOIUrl":"10.1016/j.matchar.2024.114703","url":null,"abstract":"<div><div>Phase and grain boundaries can effectively strengthen dual-phase high-entropy alloys (HEAs), but as service temperature increases, they could also become sources of weakness and damage. In this work, microstructures with different phase and grain boundary densities were designed in a hypoeutectic HEA to compare their different effects on cracking behavior at elevated temperatures. The tensile ductility significantly increased by reducing the intergranular fracture with decreased grain boundary density. The analyses revealed that the grain boundary was prone to crack at the triple junctions and served as the crack propagation path. Differently, although the phase boundary also cracked preferentially, it was highly resistant to crack propagation by its serrated morphology and defects emission at the crack tip. The directionally solidified sample further proved the benefit by suppressing the intergranular cracking, achieving a higher yield strength of ∼701 MPa and considerable tensile ductility of ∼31.5 % at 800 °C. These findings create a microstructural optimization pathway based on the cracking mechanisms, aiming to produce high-performance dual-phase HEAs for application in a wide temperature range.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114703"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130831","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 : 2025-02-01DOI: 10.1016/j.matchar.2025.114721
Wenjie Zheng , Shuyan Wang , Qi Yang , Wuhua Yuan
In this study, quenched aluminum–lithium alloy specimens were subjected to precompression deformation (0 %–5 %). Then, the influence of predeformation amounts on the residual stress, microstructure, and mechanical properties of alloy specimens was investigated. Results revealed that the amount of residual stress release first increased and then decreased with increasing predeformation amount. The efficacy of residual stress release was influenced by the initial residual stress in the specimens and their mechanical properties at the surface and core. X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy revealed that due to predeformation, more dislocations were retained in the matrix of the specimen. These dislocations provided nucleation sites for the formation of precipitates. The T1 phase content gradually increased with increasing predeformation amount, whereas the θˊ phase content first increased and then decreased. The contribution of microstructural evolution to the yield strength (YS) of specimens was further analyzed to elucidate the relation between the strengthening mechanism and microstructure. As the predeformation amount increased from 0 % to 2 %, the increase in YS was impacted by an increase in the dislocation density and the continuous precipitation of T1 and θˊ phases. When the predeformation amount was increased to 3 %–5 %, the YS of the specimen increased primarily due to T1 phase precipitation.
{"title":"Influence of precompression deformation on the residual stress, microstructure, and mechanical properties of aluminum–lithium alloys","authors":"Wenjie Zheng , Shuyan Wang , Qi Yang , Wuhua Yuan","doi":"10.1016/j.matchar.2025.114721","DOIUrl":"10.1016/j.matchar.2025.114721","url":null,"abstract":"<div><div>In this study, quenched aluminum–lithium alloy specimens were subjected to precompression deformation (0 %–5 %). Then, the influence of predeformation amounts on the residual stress, microstructure, and mechanical properties of alloy specimens was investigated. Results revealed that the amount of residual stress release first increased and then decreased with increasing predeformation amount. The efficacy of residual stress release was influenced by the initial residual stress in the specimens and their mechanical properties at the surface and core. X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy revealed that due to predeformation, more dislocations were retained in the matrix of the specimen. These dislocations provided nucleation sites for the formation of precipitates. The T1 phase content gradually increased with increasing predeformation amount, whereas the θˊ phase content first increased and then decreased. The contribution of microstructural evolution to the yield strength (YS) of specimens was further analyzed to elucidate the relation between the strengthening mechanism and microstructure. As the predeformation amount increased from 0 % to 2 %, the increase in YS was impacted by an increase in the dislocation density and the continuous precipitation of T1 and θˊ phases. When the predeformation amount was increased to 3 %–5 %, the YS of the specimen increased primarily due to T1 phase precipitation.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114721"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130910","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 : 2025-02-01DOI: 10.1016/j.matchar.2024.114683
Bingyuan Han , Ruihua Zhang , Jun Yang , Yuxiang Liu , Yonglin Zhao , Xianghan Gao , Han Li
In this paper, the wetting and interfacial behavior of Al-Si-Cu-Zn-Ni-xY (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) brazing filler alloys on 7072 aluminum alloy substrate are investigated. Results show that the trace element Y can effectively improve the stability of the characteristic transition temperature of brazing filler alloys and reduce the melting interval at the same time. Accroding to the results of molecular dynamics simulations and arc wetting tests, the surface wetting process of the filler alloy is of five stages, i.e., preheating film-breaking stage, initial stage, rapid diffusion stage, limited diffusion stage and stabilization stage. When the content of Y in the Al-Si-Cu-Zn-Ni-Y brazing alloy increased from 0 wt% to 0.8 wt%, the wetting diffusion area of the brazing alloy increased from 261.298 mm2 to 305.658 mm2, and the wetting angle decreased from 18.28°to 12.857°。The microstructure shows that element Y can purify the wetted interface because Y reacts easily with Al2(Cu,Ni) in the brazing alloy to form Al4.4(Cu,Ni)6.6Y phase. The latter phase distributes discretely along the wetting interface and thus, the fluidity of the brazing alloy is improved.
{"title":"Effect of Y contents on surface wetting and interfacial behavior of Al-Si-Cu-Zn-Ni-xY brazing filler alloys on 7072 aluminum alloy","authors":"Bingyuan Han , Ruihua Zhang , Jun Yang , Yuxiang Liu , Yonglin Zhao , Xianghan Gao , Han Li","doi":"10.1016/j.matchar.2024.114683","DOIUrl":"10.1016/j.matchar.2024.114683","url":null,"abstract":"<div><div>In this paper, the wetting and interfacial behavior of Al-Si-Cu-Zn-Ni-<em>x</em>Y (<em>x</em> = 0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) brazing filler alloys on 7072 aluminum alloy substrate are investigated. Results show that the trace element Y can effectively improve the stability of the characteristic transition temperature of brazing filler alloys and reduce the melting interval at the same time. Accroding to the results of molecular dynamics simulations and arc wetting tests, the surface wetting process of the filler alloy is of five stages, i.e., preheating film-breaking stage, initial stage, rapid diffusion stage, limited diffusion stage and stabilization stage. When the content of Y in the Al-Si-Cu-Zn-Ni-Y brazing alloy increased from 0 wt% to 0.8 wt%, the wetting diffusion area of the brazing alloy increased from 261.298 mm<sup>2</sup> to 305.658 mm<sup>2</sup>, and the wetting angle decreased from 18.28°to 12.857°。The microstructure shows that element Y can purify the wetted interface because Y reacts easily with Al<sub>2</sub>(Cu,Ni) in the brazing alloy to form Al<sub>4.4</sub>(Cu,Ni)<sub>6.6</sub>Y phase. The latter phase distributes discretely along the wetting interface and thus, the fluidity of the brazing alloy is improved.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114683"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143131008","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 : 2025-02-01DOI: 10.1016/j.matchar.2024.114650
Mahdi Mahmoudiniya , Anne-Sophie Thorr , Roumen H. Petrov , Marcel J.M. Hermans , Leo A.I. Kestens
Wire arc additive manufacturing (WAAM) is a significant area of interest within the field of additive manufacturing (AM). In the present research, WAAM technology was employed to deposit a Ni-based alloy on a ductile cast iron substrate to fabricate a bimetallic structure of Ni-45 %Fe alloy and ductile cast iron. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron back scattered diffraction (EBSD) and X-ray diffraction (XRD) were used to study phase transformations, microstructure and crystallographic texture development in interfacial regions as well as deposited material. The mechanical properties were also studied using micro-hardness and profilometry-based indentation plastometry (PIP) measurements. The results showed that a wide variety of phases are generated within the heat-affected zone (HAZ) and partially melted zone (PMZ). These phases form complex microstructures with single and double shell morphology. The deposited alloy has a face-centred cubic (FCC) structure, with some carbides and graphite that are formed during the solidification of the first deposited layer. The compositional changes were also observed across the interface. The texture of the deposited alloy showed around 30° deviation from 〈100〉 II building direction due to the shape and overlap of the melt pools. The present results provide a better understanding of interface development mechanisms during WAAM of bimetallic structures. The peak of the hardness across the interface was observed in PMZ because of the formation of a martensitic matrix. The PIP measurements showed that the and the of deposited alloy are lower than the cast iron base metal.
{"title":"Wire arc additive manufacturing of NiFe alloy/ductile cast iron bimetallic structure; phase transformations, microstructure and crystallographic texture","authors":"Mahdi Mahmoudiniya , Anne-Sophie Thorr , Roumen H. Petrov , Marcel J.M. Hermans , Leo A.I. Kestens","doi":"10.1016/j.matchar.2024.114650","DOIUrl":"10.1016/j.matchar.2024.114650","url":null,"abstract":"<div><div>Wire arc additive manufacturing (WAAM) is a significant area of interest within the field of additive manufacturing (AM). In the present research, WAAM technology was employed to deposit a Ni-based alloy on a ductile cast iron substrate to fabricate a bimetallic structure of Ni-45 %Fe alloy and ductile cast iron. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron back scattered diffraction (EBSD) and X-ray diffraction (XRD) were used to study phase transformations, microstructure and crystallographic texture development in interfacial regions as well as deposited material. The mechanical properties were also studied using micro-hardness and profilometry-based indentation plastometry (PIP) measurements. The results showed that a wide variety of phases are generated within the heat-affected zone (HAZ) and partially melted zone (PMZ). These phases form complex microstructures with single and double shell morphology. The deposited alloy has a face-centred cubic (FCC) structure, with some carbides and graphite that are formed during the solidification of the first deposited layer. The compositional changes were also observed across the interface. The texture of the deposited alloy showed around 30° deviation from 〈100〉 II building direction due to the shape and overlap of the melt pools. The present results provide a better understanding of interface development mechanisms during WAAM of bimetallic structures. The peak of the hardness across the interface was observed in PMZ because of the formation of a martensitic matrix. The PIP measurements showed that the <span><math><msub><mi>σ</mi><mi>y</mi></msub></math></span> and the <span><math><mi>UTS</mi></math></span> of deposited alloy are lower than the cast iron base metal.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114650"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130688","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 : 2025-02-01DOI: 10.1016/j.matchar.2024.114708
Yulai Xu , Lijun Fan , Liuyang Li , Liqin Shen , Xiaofei Wu , Xingyu Wang , Zhilong Tan
Effect of cobalt on microstructures and mechanical properties of Nimonic 80A has been investigated. Room temperature tensile strength increases by about 8.8%, and stress-rupture life at 750 °C/310 MPa increases by about 53.0% of 5Co alloy. Area fraction of γ' linearly increases from about 59.6% to 65.6% and average diameter of γ' significantly decreases from about 21.0 to 6.6 nm with the increased Co content after full heat treatment. The γ' exhibits a coherent orientation relationship with γ on {100} and {110}. Area fraction of γ' decreases and average size of γ' increases after stress-rupture test for each alloy due to the coarsening of approximately spherical γ' particles, but addition of Co can stabilize γ' phase because the average size of γ' in 5Co alloy is smaller than that in 2Co alloy. The lattice misfit of γ'/γ increases with the increased Co content both before and after stress-rupture test, but the lattice misfit for each alloy slightly decreases after stress-rupture test compared with that after full heat treatment. The addition of Co can easily lead to the appearance of numerous dislocations, and significantly varied interplanar spacing of {111} and {200} in γ phase. The blocky Cr23C6 carbide prefers to precipitate at GBs with an orientation relationship with the nearby γ matrix on {100}, the Cr23C6 carbide can suppress the movement of dislocations and grain boundaries, which benefits better mechanical properties.
{"title":"Microstructure evolution and improved mechanical properties of a cobalt modified nickel-based superalloy","authors":"Yulai Xu , Lijun Fan , Liuyang Li , Liqin Shen , Xiaofei Wu , Xingyu Wang , Zhilong Tan","doi":"10.1016/j.matchar.2024.114708","DOIUrl":"10.1016/j.matchar.2024.114708","url":null,"abstract":"<div><div>Effect of cobalt on microstructures and mechanical properties of Nimonic 80A has been investigated. Room temperature tensile strength increases by about 8.8%, and stress-rupture life at 750 °C/310 MPa increases by about 53.0% of 5Co alloy. Area fraction of γ' linearly increases from about 59.6% to 65.6% and average diameter of γ' significantly decreases from about 21.0 to 6.6 nm with the increased Co content after full heat treatment. The γ' exhibits a coherent orientation relationship with γ on {100} and {110}. Area fraction of γ' decreases and average size of γ' increases after stress-rupture test for each alloy due to the coarsening of approximately spherical γ' particles, but addition of Co can stabilize γ' phase because the average size of γ' in 5Co alloy is smaller than that in 2Co alloy. The lattice misfit of γ'/γ increases with the increased Co content both before and after stress-rupture test, but the lattice misfit for each alloy slightly decreases after stress-rupture test compared with that after full heat treatment. The addition of Co can easily lead to the appearance of numerous dislocations, and significantly varied interplanar spacing of {111} and {200} in γ phase. The blocky Cr<sub>23</sub>C<sub>6</sub> carbide prefers to precipitate at GBs with an orientation relationship with the nearby γ matrix on {100}, the Cr<sub>23</sub>C<sub>6</sub> carbide can suppress the movement of dislocations and grain boundaries, which benefits better mechanical properties.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114708"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130905","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 : 2025-02-01DOI: 10.1016/j.matchar.2025.114714
Abdelkader Khalfallah , Sid Ahmed Amzert , Fahd Arbaoui , Nacereddine Titouche , Noureddine Selmi , Piotr Bazarnik , Hiba Azzeddine , Thierry Baudin , François Brisset , Yi Huang , Terence G. Langdon
The corrosion behavior of a commercial Al-6061 alloy was explored in a 3.5 % (wt%) NaCl solution after high-pressure torsion (HPT) processing at room temperature for numbers of revolutions of N = 0, 1/2, 2 and 10 turns. The microstructures revealed by electron backscatter diffraction (EBSD) showed excellent grain refinement from 121 ± 5 to 0.44 ± 0.1 μm after N = 10 turns with a high fraction of high-angle grain boundaries (∼65 %). The results from electrochemical tests demonstrate that HPT processing significantly improves the corrosion resistance and reduces the corrosion rate due to a combination of grain refinement, an increased dislocation density and texture weakening. The corrosion mechanism was not affected by the HPT processing and found to be controlled by charge transfer. The corrosion morphology of the HPT-processed sample taken through N = 10 turns and observed after 14 days of immersion showed a smooth surface except for the presence of some corrosion microcracks around large particles enriched with Zn and Fe elements.
{"title":"Corrosion performance of Al-6061 alloy after high-pressure torsion processing","authors":"Abdelkader Khalfallah , Sid Ahmed Amzert , Fahd Arbaoui , Nacereddine Titouche , Noureddine Selmi , Piotr Bazarnik , Hiba Azzeddine , Thierry Baudin , François Brisset , Yi Huang , Terence G. Langdon","doi":"10.1016/j.matchar.2025.114714","DOIUrl":"10.1016/j.matchar.2025.114714","url":null,"abstract":"<div><div>The corrosion behavior of a commercial Al-6061 alloy was explored in a 3.5 % (wt%) NaCl solution after high-pressure torsion (HPT) processing at room temperature for numbers of revolutions of <em>N</em> = 0, 1/2, 2 and 10 turns. The microstructures revealed by electron backscatter diffraction (EBSD) showed excellent grain refinement from 121 ± 5 to 0.44 ± 0.1 μm after <em>N</em> = 10 turns with a high fraction of high-angle grain boundaries (∼65 %). The results from electrochemical tests demonstrate that HPT processing significantly improves the corrosion resistance and reduces the corrosion rate due to a combination of grain refinement, an increased dislocation density and texture weakening. The corrosion mechanism was not affected by the HPT processing and found to be controlled by charge transfer. The corrosion morphology of the HPT-processed sample taken through <em>N</em> = 10 turns and observed after 14 days of immersion showed a smooth surface except for the presence of some corrosion microcracks around large particles enriched with Zn and Fe elements.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114714"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130908","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 : 2025-02-01DOI: 10.1016/j.matchar.2024.114669
Jin-Bum Kim, Junha Lee, In-Gyeong Kim, Yong-Bum Park, Se-Eun Shin
{"title":"Erratum to “The effect of thermomechanical treatment on the electrodeposited Invar alloy for FMM” [Matarials Characterization, Volume 210, (2024) 113809]","authors":"Jin-Bum Kim, Junha Lee, In-Gyeong Kim, Yong-Bum Park, Se-Eun Shin","doi":"10.1016/j.matchar.2024.114669","DOIUrl":"10.1016/j.matchar.2024.114669","url":null,"abstract":"","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114669"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The η-Ni6AlNb in GH4169D could pin grain boundaries, and hinder crack propagation. However, the dissolution of the η phase at 1020 °C causes the notch sensitivity in GH4169D. So low-melting-point alloys, Cu-30Ag-32Zn-1Sn (wt%) (CuAgZnSn), were employed to achieve high-strength brazing of GH4169D at different brazing temperatures (850, 870, 890, 910, and 930 °C) for 30 min and 890 °C for different holding time (10, 60, and 120 min). The influence of the brazing process on the interface microstructure, mechanical properties, and fracture behavior of GH4169D/CuAgZnSn/GH4169D joints was investigated. The brazed seam (BS) was mainly composed of (Cu, Zn)ss and (Ag, Zn)ss. The BS achieved isothermal solidification at 890 °C for 30 min and an ordered solid solution Cu2NiZn formed at 890 °C for 60 min. Meanwhile, the content of (Ag, Cu, Zn)ss decreased. However, as the holding time increased from 60 min to 120 min, the content of (Ag, Cu, Zn)ss increased from 0.7 % to 40.3 %. This was mainly because of the reduced solid solubility of Ag in the (Cu, Zn, Ni)ss as the Ni increased. The interface structure of the brazed joint at 890 °C for 60 min was GH4169D/Cu2NiZn + Cr-rich (Cr, Ni, Cu)ss/Cu2NiZn + Ag-rich (Ag, Cu, Zn)ss + Cu-rich (Cu, Zn, Ni, Cr)ss/Cu2NiZn + Cr-rich (Cr, Ni, Cu)ss/GH4169D. The shear strength of the joints reached 708 MPa. As the holding times increased, the crack initiated from the BS/substrates interface with drastic changes in hardness to the BS. The fracture morphology changed from typical brittle cleavage fracture characteristics to dimples and cleavage steps.
{"title":"High-strength GH4169D joint brazed with medium temperature Cu-30Ag-32Zn-1Sn filler metal","authors":"Xin Jiang, Honggang Dong, Liangliang Zhang, Zhiwei Qin, Yinchen Wang, Bomin Zhao, Peng Li","doi":"10.1016/j.matchar.2024.114662","DOIUrl":"10.1016/j.matchar.2024.114662","url":null,"abstract":"<div><div>The η-Ni<sub>6</sub>AlNb in GH4169D could pin grain boundaries, and hinder crack propagation. However, the dissolution of the η phase at 1020 °C causes the notch sensitivity in GH4169D. So low-melting-point alloys, Cu-30Ag-32Zn-1Sn (wt%) (CuAgZnSn), were employed to achieve high-strength brazing of GH4169D at different brazing temperatures (850, 870, 890, 910, and 930 °C) for 30 min and 890 °C for different holding time (10, 60, and 120 min). The influence of the brazing process on the interface microstructure, mechanical properties, and fracture behavior of GH4169D/CuAgZnSn/GH4169D joints was investigated. The brazed seam (BS) was mainly composed of (Cu, Zn)<sub>ss</sub> and (Ag, Zn)<sub>ss</sub>. The BS achieved isothermal solidification at 890 °C for 30 min and an ordered solid solution Cu<sub>2</sub>NiZn formed at 890 °C for 60 min. Meanwhile, the content of (Ag, Cu, Zn)<sub>ss</sub> decreased. However, as the holding time increased from 60 min to 120 min, the content of (Ag, Cu, Zn)<sub>ss</sub> increased from 0.7 % to 40.3 %. This was mainly because of the reduced solid solubility of Ag in the (Cu, Zn, Ni)<sub>ss</sub> as the Ni increased. The interface structure of the brazed joint at 890 °C for 60 min was GH4169D/Cu<sub>2</sub>NiZn + Cr-rich (Cr, Ni, Cu)<sub>ss</sub>/Cu<sub>2</sub>NiZn + Ag-rich (Ag, Cu, Zn)<sub>ss</sub> + Cu-rich (Cu, Zn, Ni, Cr)<sub>ss</sub>/Cu<sub>2</sub>NiZn + Cr-rich (Cr, Ni, Cu)<sub>ss</sub>/GH4169D. The shear strength of the joints reached 708 MPa. As the holding times increased, the crack initiated from the BS/substrates interface with drastic changes in hardness to the BS. The fracture morphology changed from typical brittle cleavage fracture characteristics to dimples and cleavage steps.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":"220 ","pages":"Article 114662"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143131005","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}