Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature
In this study, the extrusion temperature (350–450 °C)-dependent microstructure evolution of AZ91 Mg alloy and its effects on the formation mechanisms of phosphate film and corrosion behavior were systematically analyzed. Results revealed that extrusion at 350 °C resulted in a refined microstructure...
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Elsevier
2025-09-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425019623 |
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| author | Haolong Bai Junlei Zhang Qiuyue Shi Xiang Chen Xuwen Yuan Shengbo Hu Chao He Qi Zhao Shuping Tan Yifu Shen Guangsheng Huang |
| author_facet | Haolong Bai Junlei Zhang Qiuyue Shi Xiang Chen Xuwen Yuan Shengbo Hu Chao He Qi Zhao Shuping Tan Yifu Shen Guangsheng Huang |
| author_sort | Haolong Bai |
| collection | DOAJ |
| description | In this study, the extrusion temperature (350–450 °C)-dependent microstructure evolution of AZ91 Mg alloy and its effects on the formation mechanisms of phosphate film and corrosion behavior were systematically analyzed. Results revealed that extrusion at 350 °C resulted in a refined microstructure with an average grain size of 8.9 μm, accompanied by an intensified basal texture (mud = 18.20) and a high proportion (64.8 %) of basal-oriented grains compared to 400 °C and 450 °C processed counterparts. The refined grain size accelerated phosphate nucleation kinetics, while the intensified basal texture and enhanced basal-oriented grain fraction promoted epitaxial growth of a dense composite film layer of MgHPO4, Al(OH)3, and MnHPO4 with an average thickness of 27 ± 2.0 μm, thereby exhibiting the lowest absolute value of corrosion current density (3.91 × 10−6 A/cm2) and superior salt spray resistance. Conversely, high-temperature extrusion (450 °C) induced grain coarsening (14.7 μm) and texture randomization (27.2.0 % basal-oriented grains), which led to a relatively thin and less uniform phosphate film with increased microcracks, thereby compromising the corrosion performance. Additionally, the precipitate evolution exhibited a non-monotonic temperature dependence, peaking at 400 °C (2.1 ± 0.45 % area fraction), but its influence diminished as the phosphating film fully developed. Additionally, the dislocation density exhibited a negligible influence on film formation and corrosion resistance. The current research offers insights into achieving phosphating film with excellent corrosion resistance through microstructural design controlled by extrusion temperature. |
| format | Article |
| id | doaj-art-0def30c718aa4ff4ada9bf6f2e4f48ac |
| institution | Kabale University |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj-art-0def30c718aa4ff4ada9bf6f2e4f48ac2025-08-20T03:59:22ZengElsevierJournal of Materials Research and Technology2238-78542025-09-01381248126210.1016/j.jmrt.2025.08.009Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperatureHaolong Bai0Junlei Zhang1Qiuyue Shi2Xiang Chen3Xuwen Yuan4Shengbo Hu5Chao He6Qi Zhao7Shuping Tan8Yifu Shen9Guangsheng Huang10College of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, ChinaCollege of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, ChinaCollege of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, ChinaCollege of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, China; Shengtak New Materials Co., Ltd., Changzhou, 213144, China; College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China; Corresponding author. College of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, China.College of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, China; Corresponding author.College of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, ChinaCollege of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, ChinaCollege of Automotive Materials, Hubei University of Automotive Technology, Shiyan, 442002, ChinaShengtak New Materials Co., Ltd., Changzhou, 213144, ChinaCollege of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, ChinaCollege of Materials Science and Engineering, Chongqing University, Chongqing, 400044, ChinaIn this study, the extrusion temperature (350–450 °C)-dependent microstructure evolution of AZ91 Mg alloy and its effects on the formation mechanisms of phosphate film and corrosion behavior were systematically analyzed. Results revealed that extrusion at 350 °C resulted in a refined microstructure with an average grain size of 8.9 μm, accompanied by an intensified basal texture (mud = 18.20) and a high proportion (64.8 %) of basal-oriented grains compared to 400 °C and 450 °C processed counterparts. The refined grain size accelerated phosphate nucleation kinetics, while the intensified basal texture and enhanced basal-oriented grain fraction promoted epitaxial growth of a dense composite film layer of MgHPO4, Al(OH)3, and MnHPO4 with an average thickness of 27 ± 2.0 μm, thereby exhibiting the lowest absolute value of corrosion current density (3.91 × 10−6 A/cm2) and superior salt spray resistance. Conversely, high-temperature extrusion (450 °C) induced grain coarsening (14.7 μm) and texture randomization (27.2.0 % basal-oriented grains), which led to a relatively thin and less uniform phosphate film with increased microcracks, thereby compromising the corrosion performance. Additionally, the precipitate evolution exhibited a non-monotonic temperature dependence, peaking at 400 °C (2.1 ± 0.45 % area fraction), but its influence diminished as the phosphating film fully developed. Additionally, the dislocation density exhibited a negligible influence on film formation and corrosion resistance. The current research offers insights into achieving phosphating film with excellent corrosion resistance through microstructural design controlled by extrusion temperature.http://www.sciencedirect.com/science/article/pii/S2238785425019623AZ91 Mg alloyExtrusion temperatureMicrostructurePhosphate filmCorrosion behavior |
| spellingShingle | Haolong Bai Junlei Zhang Qiuyue Shi Xiang Chen Xuwen Yuan Shengbo Hu Chao He Qi Zhao Shuping Tan Yifu Shen Guangsheng Huang Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature Journal of Materials Research and Technology AZ91 Mg alloy Extrusion temperature Microstructure Phosphate film Corrosion behavior |
| title | Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature |
| title_full | Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature |
| title_fullStr | Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature |
| title_full_unstemmed | Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature |
| title_short | Microstructure-dependent phosphating film formation and its corrosion behavior in AZ91 Mg alloy: Effect of extrusion temperature |
| title_sort | microstructure dependent phosphating film formation and its corrosion behavior in az91 mg alloy effect of extrusion temperature |
| topic | AZ91 Mg alloy Extrusion temperature Microstructure Phosphate film Corrosion behavior |
| url | http://www.sciencedirect.com/science/article/pii/S2238785425019623 |
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