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Phase Evolution and Glass Formation in an Fe-Based Alloy

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金属学报:英文版 2023年第9期36卷 1502-1510页

作者： Ping Huang Yutong Shi Wei Zhang Suode Zhang Yinglei Ren keqiang qiu Jianqiang Wang School of Materials Science and Engineering Shenyang University of TechnologyShenyang110870China Shenyang National Laboratory for Materials Science Institute of Metal ResearchCASShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

The understanding of phase competing is of pretty importance in designing high glass-forming systems. In this work, it has been investigated experimentally and theoretically the phase evolution and glass formation of a wedge-casting Fe-based alloy. The results indicated that the phase formation was sensitive to the wedge position, i.e., there were amorphous phase, Fe_(2)P, {Fe, Ni} and α-Fe precipitates as well as M_(23)B_(6) phase at the distances of 3, 10 and 20 mm away from the wedge-tip, respectively. These were closely connected with the variation of cooling rate, embodied in the heat transfer at the solidification process. Furthermore, we constructed the time–temperature-transformation (TTT) diagrams of the iron-based alloy and these crystal phases through calculating Rc-related functions. Finally, the glass-forming features of the wedge-shaped Fe-based alloy have been elucidated in accordance with a crystallization kinetics analysis of the recorded temperature data and the phase selection competition. This research provides us an insight into in-depth understanding bulk metallic glass from the perspective of kinetics competition of crystallization phases.

关键词： Bulk metallic glass Phase evolution Crystallization kinetics Cooling rate

Multilayer dielectric grating pillar-removal damage induced by a picosecond laser

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High Power Laser Science and Engineering 2022年第6期10卷 66-74页

作者： Kun Shuai Xiaofeng Liu Yuanan Zhao keqiang qiu Dawei Li He Gong Jian Sun Li Zhou Youen Jiang Yaping Dai Jianda Shao Zhilin Xia School of Materials Science and Engineering Wuhan University of TechnologyWuhanChina Laboratory of Thin Film Optics Shanghai Institute of Optics and Fine MechanicsShanghaiChina National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefeiChina School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghaiChina National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsCASShanghaiChina Research Center of Laser Fusion China Academy of Engineering PhysicsMianyangChina Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhouChina

Multilayer dielectric gratings typically remove multiple-grating pillars after picosecond laser irradiation;however,the dynamic formation process of the removal is still *** this study,the damage morphologies of multilayer dielectric gratings induced by an 8.6-ps laser pulse were closely *** damage included the removal of a single grating pillar and consecutive adjacent grating pillars and did not involve the destruction of the internal high-reflection mirror *** analysis of the two damage morphological characteristics indicated the removal of adjacent pillars was related to an impact process caused by the eruption of localized materials from the left-hand pillar,exerting impact pressure on its adjacent pillars and eventually resulting in multiple pillar removal.A finite-element strain model was used to calculate the stress distribution of the grating after *** to the electric field distribution,the eruptive pressure of the dielectric materials after ionization was also *** results suggest that the eruptive pressure resulted in a stress concentration at the root of the adjacent pillar that was sufficient to cause damage,corresponding to the experimental removal of the adjacent pillar from the *** study provides further understanding of the laser-induced damage behavior of grating pillars and some insights into reducing the undesirable damage process for practical applications.

关键词： grating pillar removal laser-induced damage multilayer dielectric gratings picosecond laser

Nanosecond laser conditioning of multilayer dielectric gratings for picosecond–petawatt laser systems

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High Power Laser Science and Engineering 2023年第6期11卷 239-248页

作者： Kun Shuai Yuanan Zhao Xiaofeng Liu Xiangkun Lin Zhilin Xia keqiang qiu Dawei Li He Gong Yan Zhou Jian Sun Li Zhou Youen Jiang Yaping Dai Jianda Shao Laboratory of Thin Film Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences(CAS)ShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Key Laboratory of Materials for High Power Laser Chinese Academy of SciencesShanghaiChina School of Materials Science and Engineering Wuhan University of TechnologyWuhanChina National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefeiChina School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghaiChina National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsCASShanghaiChina Research Center of Laser Fusion China Academy of Engineering PhysicsMianyangChina Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhouChina

Multilayer dielectric gratings(MLDGs)are crucial for pulse compression in picosecond-petawatt laser *** nodular defects,embedded in coating stacks during multilayer deposition,influence the lithographic process and performance of the final MLDG *** this study,the integration of nanosecond laser conditioning(NLC)into different manufacturing stages of MLDGs was proposed for the first time on multilayer dielectric films(MLDFs)and final grating products to improve laser-induced damage *** results suggest that the remaining nodular ejection pits introduced by the two protocols exhibit a high nanosecond laser damage resistance,which remains stable when the irradiated laser fluence is more than twice the nanosecond-laser-induced damage threshold(nanosecond-LIDT)of the unconditioned ***,the picosecond-LIDT of the nodular ej ection pit conditioned on the MLDFs was approximately 40%higher than that of the nodular defects,and the loss of the grating structure surrounding the nodular defects was ***,NLC is an effective strategy for improving the laser damage resistance of MLDGs.

关键词： laser-induced damage threshold multilayer dielectric gratings nanosecond laser conditioning nodular defects picosecond-petawatt laser systems

Morphology and microstructure of rapidly solidified tin-lead alloy powders

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China Foundry 2014年第5期11卷 428-434页

作者： Xiang Qingchun Zhang Wei qiu keqiang Qu Yingdong Li Rongde School of Materials Science and Engineering Shenyang University of Technology

Sn60Pb40 alloy powders were fabricated using the planar flow casting(PFC) atomization process. By using OM, SEM and EPMA, the characteristics of the morphologies and microstructures of the powders have been investigated. It is observed that the environment of ambient gas in the atomization box has great effects on the morphology of the alloy powders. The microstructures of Sn60Pb40 alloy powders produced by the PFC atomization process are completely composed of eutectic, which is made up of both oversaturated α solid solution and β solid solution. The microstructures of small size powders are extraordinarily undeveloped dendritic eutectic, in which the large majority of the α phase appears nearly spherical, evidently since the cooling rate is higher and the under-cooling is larger. As for the large size powders, since the cooling rate and undercooling are relatively low, lamellar α phase apparently increases in the eutectic microstructures of these powders, and there is even typical lamellar eutectic structure clearly observed in some micro-areas. After remelting tests by DTA, the microstructures of small size powders are transformed, which become composed of large crumby α phase and eutectic(α+β), while those of large size powders change into classical tin-lead structures of primary α phase plus lamellar eutectic(α+β). By studying the microstructures of tin-lead alloy powders, a model has been proposed to predict the microstructure formation of Sn60Pb40 alloy powders.

关键词： rapid solidification planar flow casting tin-lead alloy metal powders microstructure

Efects of minor amounts of scandium on microstructure and mechanical properties of ZA27 alloy

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China Foundry 2013年第5期10卷 294-298页

作者： Xiang Qingchun Zhang Wei Wang Ruichun qiu keqiang Li Rongde School of Materials Science Engineering Shenyang University of Technology

The influences of minor amounts of scandium on the microstructure and mechanical properties of as-cast ZA27 alloy have been experimentally *** experimental results show that as far as the Sc addition is individually concerned,the refinement result of the as-cast ZA27 alloy with 0.5wt.%Sc addition is comparatively *** alloying with minor amounts of Sc,the coarse dendrites of the ZA27 alloy are refined and transformed into the uniform and small equiaxed grain microstructure;also the eutectics among the grain boundaries become *** test results of mechanical properties show that the tensile strength and hardness of the as-cast ZA27 alloy containing 0.5wt.%Sc approach 495 MPa and 120.2 HB,increase by28.5%and 33.1%,respectively,compared with those of the ZA27 alloy with no addition of Sc element,while the elongation of the alloy is improved to 7.6%from 2.7%.The SEM,EDAX and XRD analyses show that in the ZA27 alloy,the trace element Sc combines with Al to form the square Al3Sc phase particles,which serve as heterogeneous nuclei,facilitating the refinement of the microstructure and the improvement of the mechanical properties of the alloy.

关键词： ZA27 alloy scandium microstructure mechanical properties heterogeneous nuclei

Fabrication of Porous Bulk Metallic Glass

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Journal of Materials Science & Technology 2005年第6期21卷 788-790页

作者： keqiang qiu+ and Yinglei REN School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023, China School of Materials Science and Engineering Shenyang University of Technology Shenyang 110023 China

An open-cell porous bulk metallic glass （BMG） with a diameter of at least 6 mm was fabricated by using an U-turn quartz tube and infiltration casting around soluble NaCI placeholders. The pore formation and glassy structure were examined by optical microscopy （OM）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the pores or cells are connected to each other and the specimen is composed of a mostly glassy phase. This paper provides a suitable method for fabrication of porous BMG and BMG with larger size in diameter.

关键词： Porous bulk metallic glass U-turn quartz tube Infiltration casting

Microstructures and formation mechanism of hypoeutectic white cast iron by isothermal electromagnetic rheocast process

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China Foundry 2010年第2期7卷 113-116页

作者： Zhang Wanning Song Dan Zhang Hongbing Li Deyuan Yuan Xiaoguang qiu keqiang Shenyang Government Investment Project Evaluation Center Shenyang 1100141 China School of Materials Science and Engineering Shenyang University of Technology Shenyang 110870 China

An investigation was made on the evolution of microstructures of hypoeutectic white cast iron slurry containing 2.5wt.%C and 1.8wt.%Si produced by rheocasting in which the solidifying alloy was vigorously agitated by electromagnetic stirrer during isothermal cooling *** results indicated that under the proper agitating temperatures and speeds applied,the dendrite structures in white cast iron slurry were gradually evolved into spherical structures during a certain agitating *** also revealed that the bent dendrites were formed by either convection force or by the growth of the dendrites themselves in the bending direction;then,as they were in solidifying,they were gradually being alternated into separated particles and into more spherical structures at the end of the isothermal cooling ***,the dendrites were granulated as the bending process proceeding,which suggested that they were caused by unwanted elements such as sulfur and phosphor usually contained in engineering cast ***-ow of the melt caused corrosion on the dendritic segments where they were weaker in strength and lower in melting temperature because of higher concentration of sulfur or *** the granulation process for such dendrites formed in the melt became possible under the ***,dendrite fragments are another factors considerable to function for spherical particles formation.A new mechanism,regarding to the rheocast structure formation of white cast iron,was suggested based on the structural evolution observed in the study.

关键词：电磁搅拌器微观结构等温过程白口铸铁亚共晶机制弯曲过程球形微粒

Application of digital pattern-less molding technology to produce art casting

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China Foundry 2014年第6期11卷 487-492页

作者： Chen Li Zhang Wei Wu Chenhong Jia Baochang Xiang Qingchun qiu keqiang Li Rongde School of Information Science and Engineering Shenyang University of Technology School of Materials Science and Engineering Shenyang University of Technology

Compared with the conventional casting process, digital pattern-less casting technology has many advantages such as good machining accuracy, a short processing cycle, and low production cost. It is a new rapid manufacturing technology for castings, integrated with CAD/CAM, casting, CNC machining and many other advanced technologies. With this digital casting technology, no pattern is needed for making molds; it is precise, f lexible, and green. Usually, art castings have complex structures and are made in small batches or even made in a single-piece, especially for large-sized art castings. So it has the shortcomings of high cost, low eff iciency and long time for making a pattern to produce art castings with the conventional casting processes. However, the digital pattern-less casting technology can be applied to fabricate art castings, since it can greatly shorten the manufacturing cycle and lower the production cost, thus having a very good prospect. In this study, based on the digital pattern-less casting technology, a plaque casting with artistic Chinese characters(a Chinese poem) was designed and manufactured, and the production process was demonstrated in detail.

关键词： digital pattern-less casting art castings

铁基非晶合金和13Cr不锈钢在超临界CO_(2)环境的腐蚀行为

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中国表面工程 2023年第1期36卷 85-94页

作者：姚莹杨柏俊张锁德邱克强沈阳工业大学材料科学与工程学院沈阳110870 中国科学院金属研究所沈阳材料科学国家研究中心沈阳110016

非晶合金由于其独特的结构、优异的耐磨耐蚀性能在海洋及CO_(2)地质封存领域展现出广阔的应用前景,有望成为超临界CO_(2)环境下钢构件的耐蚀涂层材料,但关于非晶合金在该环境下的腐蚀行为鲜有报道.利用高温高压反应釜对SAM2X5铁基非晶... 详细信息

非晶合金由于其独特的结构、优异的耐磨耐蚀性能在海洋及CO_(2)地质封存领域展现出广阔的应用前景,有望成为超临界CO_(2)环境下钢构件的耐蚀涂层材料,但关于非晶合金在该环境下的腐蚀行为鲜有报道.利用高温高压反应釜对SAM2X5铁基非晶合金与13Cr马氏体不锈钢在温度80℃,压力10MPa的模拟环境下进行腐蚀行为对比研究.通过XRD、DSC、CLSM、SEM、XPS以及电化学Mott-Schottky测试等方法对两种材料的微观结构、腐蚀形貌以及表面膜成分及结构进行表征与分析.研究结果表明:在高温高压的超临界CO_(2)环境下进行168 h腐蚀试验后,13Cr不锈钢表面发生严重的点蚀,而铁基非晶合金表面无点蚀发生;非晶合金表面膜除Fe和Cr外,富含大量的Si元素,会促进形成稳定致密的钝化膜;13Cr不锈钢表面膜为p型半导体,非晶合金表面膜为n型半导体,13Cr不锈钢钝化膜载流子密度远高于铁基非晶合金.证实了在该环境下铁基非晶合金的耐蚀性能远优于13Cr不锈钢.

关键词：铁基非晶合金腐蚀行为超临界CO_(2) XPS