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Journal of Iron and Steel Research International 2017年第10期24卷 1048-1058页

作者： Meng-xuan Guo Kai-xiang Gao Wu-rong Wang Xi-cheng Wei School of Materials Science and Engineering Shanghai UniversityShanghai 200072China

al-si coated ultra-high strength steel（UHSS）has been commonly applied in hot stamping *** influence of austenitizing temperature on microstructure of al-si coating of UHSS during hot stamping process and its tribological behavior against H13 steel under elevated temperature were simulatively *** austenitizing temperature of al-si coated UHSS and its microstructual evolution were confirmed and analyzed by differential scanning calorimetry and scanning electron microscopy.A novel approach to tribological testing by replicating hot stamping process temperature history was *** show that the hard and stable phases Fe_2al_5＋Feal_2 formed on al-si coating surface after exposure to 930°C for 5 min,which was found to be correlated to the tribological behavior of *** friction coefficient of coated steel was more stable and higher than that of uncoated *** main wear mechanism of al-si coated UHSS was adhesion wear,while abrasive wear was dominant for the uncoated UHSS.

关键词： Hot stamping al-si coating Ultra-high strength steel Intermetallic compound Diffusion Friction coefficient Adhesive wear

Enhancing ductility of the al-si coating on hot stamping steel by controlling the Fe-al phase transformation during austenitization

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Science China(Technological Sciences) 2014年第9期57卷 1785-1793页

作者： GUI ZhongXiang LIANG WeiKang ZHANG YiSheng State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology

In this study, austenitizing heat treatment before hot stamping of al-10% si coated boron steel is first investigated through en- vironment scanning electron microscopy （ESEM） equipped with energy dispersive x-ray analysis （EDAX）. The cracking be- havior of the coating was evaluated using Gleeble 3500, a thermo-mechanical simulator under uniaxial plastic deformation at elevated temperatures. The extent and number of cracks developed in the coating were carefully assessed through an optical microscope. The coating layer under hot-dipped condition consists of an al-si eutectic matrix, Fe2al7si, Fe3al2si3 and Fe2al5, from the coating surface to the steel substrate. The coating layer remains dense, continuous and smooth. During austenitization, the al-rich Fe-al intermetallics in the coating transform to more Fe-rich intermetallics, promoted by the Fe diffusion process. The coating finally shows the coexistence of two types of Fe-al intermetallics, namely, Feal2 and Feal. Microcracks and Kirkendall voids occur in the coating layer and diffusion zone, respectively. The coating is heavily cracked and broken into segments during the hot tensile tests. Bare steel exposed between the separate segments of the coating is oxidized and covered with a thin FeOx layer. The appearance of the oxide decreases the adhesion of the al-si coating. It is found that the ductile Feal is preferred as a coating microstructure instead of the brittle Feal2. Therefore, the ductility of the al-si coating on hot stamping boron steer could be enhanced by controlling the ductile Fe-rich intermetallic phase transformations within it during austenitization. Experiments indicate that a higher austenitizing temperature or longer dwell time facilitate the Fe-rich inter- metallics transformation, increasing the volume fraction of Feal. This phase transformation also contributes to reducing the crack density and depth.

关键词： hot stamping al-si coating coating crack phase transformation ductility

Influence of Thermal Modification on al-si coating of Hot-Stamped 22MnB5 Steel:Microstructure,Phase Transformation,and Mechanical Properties

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Journal of Shanghai Jiaotong university(Science) 2021年第6期26卷 747-756页

作者： WANG Qiongyan LIN Wenhu LI Fang SHEN Chen HUA Xueming School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Center for Adaptive System Engineering ShanghaiTech UniversityShanghai 201210China

The hot-stamped steel with ultrahigh strength is a promising material for the fabrication of automotive ***,the coating on the sheet surface leads to a softening problem in the welded *** of the costly coating removal process,heat treatment is an economical and effective method for the diffusion process,which can decrease the al concentration in the *** this study,a preheating treatment was carried out on al-si-coated 22MnB5 hot-stamped steels for the homogeneity of al,followed by laser welding and hot *** effects of the preheating on the microstructure and mechanical properties of the laser-welded joints were *** the preheating treatment,the al-si coating transformed into an Fe-al intermetallic compound and the difference in al content between the coating and substrate was *** al content in the weld of the specimen with the preheating treatment was reduced,compared with that without the preheating *** amount ofδ-ferrite in the weld after laser welding was reduced *** distribution of long-bland-like segregation was changed to a fine and uniform *** the preheating treatment,the tensile strength of the welded joint was significantly improved and comparable to that of the decoated *** conclusion,the preheating treatment before the welding is an effective method to suppress the formation ofδ-ferrite and improve the mechanical properties of the welded joint.

关键词： hot-stamped steel laser welding al-si coating microstructure mechanical properties

EFFECT OF DUCTILE-BRITYLE TRANsiTION TEMPERATURE OF al-si coating ON FATIGUE PROPERTIES OF Ni-BASE SUPERalLOYS

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Acta Metallurgica sinica(English Letters) 1990年第6期3卷 435-438页

作者： ZHANG Detang Beijing Institute of Aeronautical Materials,Beijing,China Beijing Institute of Aeronautical Materials,Beijing 100095,China

The effect of al content on the ductile-brittle transition temperature of al-si coating and the effect of fracture *** the al-si coating on the fatigue properties of Ni-base superallovs have been investigated to propose the theoretical basis of search for an optimum of mechanical properties of the high temperature coating on Ni-base alloys.

关键词： al-si coating Ni-base superalloy ductile-brittle transition temperature fatigue

Preparation and Oxidation Behaviour of an al-si coating on a Ni3al Based single Crystal Superalloy IC21

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Preparation and Oxidation Behaviour of an Al-Si Coating on a...

Review on Hydrogen Embrittlement of Press-hardened Steels for Automotive Applications

中国材料大会2012

作者： Yuzhuo Liu Qiong Wu Shusuo Li Yue Ma Shengkai Gong School of Material Science and Engineering Beihang University

ISBN: (纸本)9783037856086;3037856084

An al-si coating was prepared on IC21 alloy by powder pack cementation. The cyclic oxidation tests were carried out at 1150℃ in air for up to 100 h. The results indicate that the oxidation resistance of IC21 alloy is significantly improved by the al-si coating due to the presence of Ni2al3 and β-Nial enriched outer layer, and si can effectively supress the outward diffusion of Mo. The oxide scales mainly consist of α-al2O3 , which is the favorite to the oxidation resistance. Phase transformation occurred from β-Nial to γ′-Ni3al and γ-Ni in the coating during oxidation. The coating still remained a certain amount of β phase after oxidation for 100h, which indicate a good protection. The microstructure change evolution was characterized, and the oxidation behavior of the coating was discussed.

关键词： Superalloy al-si coating High-temperature oxidation β-Nial

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Acta Metallurgica sinica(English Letters) 2023年第7期36卷 1123-1143页

作者： Z.Wang Q.Lu Z.H.Cao H.Chen M.X.Huang J.F.Wang General Motors China Science Lab Shanghai201206China Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong Kong999077China Key Laboratory for Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing100084China

Press-hardened steel(PHS)with an ultimate tensile strength(UTS)of 1500 MPa has been widely used in automotive body-in-white in the last two decades,due to its ultra-high strength and excellent formability that is achieved by hot stamping ***,the application of PHS with UTS exceeding 1500 MPa in automotive industry could be deferred due to the increased risk of hydrogen *** reduce this kind of risk,recent research efforts have been focused on various ways to optimize the microstructure of *** present review intends to summarize these efforts,to highlight present solutions to address hydrogen embrittlement,and to shed light on directions for future *** influence of microstructure on the hydrogen embrittlement of PHS has been discussed in terms of both the steel substrate and the surface *** substrate part covers the influence of martensite,carbides,inclusions,and retained austenite,while the surface part covers decarburization and oxidation,pre-coating,and trimming.

关键词： Hot stamping Press-hardened steels coating-free Hydrogen embrittlement Fracture al-si coating

Laser Oscillating of Nickel alloyed Welds on Press‑Hardened Steel

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 247-256页

作者： Qian Sun Zhenghui Zhang Xiaonan Wang Qingyu Zhang Zhenguang Liu School of Mechanical and Electrical Engineering Soochow UniversitySuzhou 215137China Shagang School of Iron and Steel Soochow UniversitySuzhou 215137China School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212000China

Laser oscillating welding was employed to fabricate al-si coated press-hardened steel(PHS)to improve the element homogeneity in the fusion *** oscillating welding was employed with various oscillation amplitudes(0 mm,0.5 mm and 1.3 mm)in this *** foil of 0.06 mm thickness was used as an interlayer between two tailored PHS *** weld morphology,elemental profile,microstructure and tensile strength of welded joints were *** results showed that full penetration weld without any weld defects were achieved for any oscillation amplitudes,and weld width increased with increasing oscillation *** the oscillation amplitudes increased,Ni and al had an uneven elemental profile due to strong stirring force,but the Ni and al content in the weld was decreased and Ni had a sharp descent compared to al *** fewδ-ferrite was presented in fusion line with the oscillation amplitudes increased to 1.3 *** oscillation amplitudes did not have an effect on the tensile properties,which was similar to that of base *** if keeping increasing the oscillation amplitudes or reducing the thickness of Ni interlayer,it has a potential risk to form more and moreδferrite such that deteriorate the mechnical properties of welded joints.

关键词： Laser oscillating welding al-si coating Press-hardened steel Nickel alloyed Microstructure and properties

Effect of Temperature on Microstructure and Formability of al-10 mass% si coatings

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Journal of Iron and Steel Research International 2016年第3期23卷 270-275页

作者： Jie ZHANG She-ming JIANG Qi-fu ZHANG Chang-sheng LIU National Engineering Laboratory Advanced coating Technology for Metals Central Iron and Steel Research InstituteBeijing 100081China School of Materials and Metallurgy Northeastern UniversityShenyang 110004LiaoningChina

The type-1aluminized（al-10mass% si）coating on hot stamped steel is used in commercial *** effect of temperature on microstructure and formability of the al-10mass% si coating was ***-dip aluminized 22MnB5 steel was heated at 870,900,930,and 1 050 ℃ for 5 *** heat treatment at different temperatures,the microstructure of al-10mass% si was characterized by field-emission scanning electron microscopy and energy-dispersive *** results show that when the al-10mass% si coating was heated at 870℃for 5min,three types of intermetallic phases were formed：two ternary Fe-si-al phases（Fe2sial7＋Fe2si2al5and Fe2sial2＋Fe2si2al5）and one binary Fe-al phase（Feal3）.The phases in the coating became Fe2sial2＋Fe2si2al5and Feal3,the binary Fe-al phase near the interface became Fe2al5 and the si-rich layers were decreased with the increase of heating *** the heat treatment was 1 050℃for 5min,the si-rich layer disappeared,the coating consisted of Feal and Fe3 al,and the Kirkendall voids were *** the heating temperature was increased through 870,900,and 930℃,the coating hardness was reduced and cracks were formed in the coating after hot *** formability of the coating with temperature change was confirmed by a hot stamping *** heated at 1 050 ℃,the coating was formable but continuous Kirkendall voids were observed.

关键词： al-si coating heating temperature microstructure formability hot-stamping

Formability of aluminum-silicon coated boron steel in hot stamping process

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Transactions of Nonferrous Metals Society of China 2014年第6期24卷 1750-1757页

作者：桂中祥梁卫抗张宜生华中科技大学材料成形与模具技术国家重点实验室武汉430074 华中科技大学材料科学与工程学院武汉430074

Flow behavior of the al-si coated boron steel was investigated with Gleeble-3500,in comparison with the uncoated *** of deformation conditions on the coating integrity was characterized by optical *** surfaces of the coated steels were inspected under *** results indicate that the ultimate tensile strength and ductility of the al-si coated boron steel are lower than those of the uncoated steel under test *** cracks occur in the coating after tensile tests;the width and density of cracks are sensitive to the deformation temperatures and strain *** bare substrate exposed between the separate coating segments is *** of the oxide degrades the al-si coating *** difference between formability of the coating layer and the substrate is *** formability of the al-si coating could be optimized by controlling the phase transformation of the ductile Fe-rich intermetallic compounds within it during the austenization.

关键词： hot stamping boron steel oxidation al-si coating crack formability

Fatigue behavior of press hardened al-si coated high strength steel

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Engineering Sciences 2014年第5期12卷 28-32页

作者： Wang Zijian Gui Zhongxiang Zhang Yisheng State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology

The fatigue behavior of press hardened al-si coated high strength steel has been investigated,and the fatigue strength turns out to be about 1 000 *** morphology of fractured and non-fractured specimen has been observed,and the coating shows significant influence on the fatigue *** difference of elastic modulus between coating and substrate led to the main cracks perpendicular to the loading *** coating close to fracture exfoliated thinly,while the coating far away from the fracture kept *** the specimen was polished to obtain high surface quality,3 types of cracks occurred during the fatigue ***’s more,inclusion particles were proved to play a crucial role in causing these cracks.

关键词： fatigue behavior high strength steel al-si coating crack