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Differential scanning calorimetry(DSC) analysis, isothermal solidification experiment and Thermo-Calc simulation were employed to investigate solidification characteristics of K417 G Ni-base superalloy. Electron probe microanalysis(EPMA) was employed to analyze the segregation characteristics. Liquidus,solidus and the formation temperatures of main phases were measured. In the process of solidification,the volume fraction of liquid dropped dramatically in the initial stage, while the dropping rate became very low in the final stage due to severe segregation of positive segregation elements into the residual liquid. The solidification began with the formation of primary γ. Then with solidification proceeding, Ti and Mo were enriched in the liquid interdendrite, which resulted in the precipitation of MC carbides in the interdendrite. Al accumulated into liquid at the initial stage, but gathered to solid later due to the precipitation of γ/γ’ eutectic at the intermediate stage of solidification. However, Co tended to segregate toward the solid phase. In the case of K417 G alloy, combining DSC analysis and isothermal solidification experiment is a good way to investigate the solidification characteristics. Thermo-Calc simulation can serve as reference to investigate K417 G alloy. 相似文献
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Muhammad-Sadeeq Balogun Yongchao Huang Weitao Qiu Hao Yang Hongbing Ji Yexiang Tong 《Materials Today》2017,20(8):425-451
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Xiangyu Chen Longfei Liu Yawei Feng Longfei Wang Zhenfeng Bian Hexing Li Zhong Lin Wang 《Materials Today》2017,20(9):501-506
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Systematic analysis about the exploitation of imidazolium based ionic liquids（ILs）,[BMIM]BF4[IL1],[EMIM]BF4 [IL2]and[BMIM]PF6[IL3]as the morphological template on the basic sol-gel method adopted synthesis of nanostructured zinc oxide（ZnO） is presented.X-ray diffraction（XRD）,particle size analysis（PSA） and scanning electron microscopy（SEM） have been employed for the characterization of structure and morphology of the synthesized ZnO particles.Well-defined capsule like shaped morphology with lower nanosize is observed for the ZnO nanoparticles with IL1 than those with IL2 and IL3.This confirms that IL1 served as an effective templating material due to their unique properties.Especially the effective aggregation of ZnO particles with a self-organized frame of IL1 was the essential factor to produce the lower nanosized ZnO with capsule shaped structure.The synthesized ZnO samples with IL2 and IL3 fabricated the flake like shaped and rod like shaped morphologies in the range of nanoscale.The formed ZnO nanoparticles with IL2 exhibit higher nanosize than the ZnO nanoparticles produced by IL1,owing to shorter length of alkyl group in its cation which restricts steric effect and permits the nanoparticles to grow longer.Even though IL3 produced the discrete ZnO nanorods,the hydrophobic nature of IL3 created the higher nanosize than the ZnO nanoparticles formed by other two ionic liquids.Antibacterial properties of the synthesized ZnO nanostructures were investigated against Staphylococcus aureus（gram positive） and Escherichia coli（gram negative） bacteria by Agar diffusion test method.Microbial experiments indicate that the synthesized ZnO samples show a wide spectrum of antimicrobial activities and performed better against S.aureus than E.coli with the same concentration of ZnO. 相似文献