Precipitation of multiple strong nanoprecipitates is crucial for the development of ultrahigh-strength structural materials with a strength of 2.5 GPa or above.Nevertheless,the ductility usually loses rapidly with str...Precipitation of multiple strong nanoprecipitates is crucial for the development of ultrahigh-strength structural materials with a strength of 2.5 GPa or above.Nevertheless,the ductility usually loses rapidly with strength due to limited dislocation mobility and high cracking tendency if coarse non-deformable precipitates are employed.Herein,we report a 2.5 GPa maraging steel strengthened by an ultrahigh den-sity of intermeshed shearable nanostructures consisting of Ni(Al,Fe)nanoprecipitates and Mo-rich(∼30 at.%)disordered clusters,both of which assume coherent interfaces.The fully coherent B2-Ni(Al,Fe)par-ticles precipitate in an extremely fast fashion,effectively accelerating local aggregation of low-diffusivity Mo atoms and promoting the formation of Mo-rich clusters surrounding them.This elemental partition was found to be further enhanced by Co addition via depleting both residual Al and Mo within the ma-trix,leading to the formation of copious yet fine intermeshed nanostructures.During plastic deformation,the interlocked nanostructures not only enhance local cutting stress by combining long-range elastic and short-range chemically ordering effects but also improve dislocation activity and resist shear-induced plastic instability.The multiple shearable nanostructures endow decent ductility(>6%)of the 2.5 GPa steel,suggesting a new paradigm for designing ultrastrong steels.展开更多
The Phased Array Feed(PAF)is considered as one of the next generation receivers for radio telescopes,which can significantly enlarge the instantaneous Field-of-View of large aperture single dish radio telescopes and e...The Phased Array Feed(PAF)is considered as one of the next generation receivers for radio telescopes,which can significantly enlarge the instantaneous Field-of-View of large aperture single dish radio telescopes and enable more flexible observing configurations.Study efforts on PAF development for radio telescopes have been made for more than two decades and have become more and more applicable.We report the development of an ambient-temperature 19 element L-band PAF system and the experimental results including its far field beam pattern and system temperature measurement,which achieve the expectations.Implementing the aperture array beam-forming method,we demonstrate a wide-field Galactic HI observations in the radio camera mode.The results indicate that this system might be applicable for strong Galactic transient detections.This system could be directly equipped to large telescopes like the Five-hundred-meter Aperture Spherical radio Telescope(FAST)and FAST array in the future.展开更多
基金This research was supported by the National Key Research and Development Program of China(nos.2022YFB3705201 and 2022YFB4602101)National Natural Science Foundation of China(nos.51971018,U20B2025,11790293,52225103,51871016,51971017,52071024,52271003)+3 种基金the Funds for Creative Research Groups of NSFC(51921001)Projects of International Cooperation and Exchanges of NSFC(nos.51961160729,52061135207)111 Project(no.BP0719004)Program for Changjiang Scholars and In-novative Research Team in University of China(no.IRT_14R05),and the Fundamental Research Funds for the Central Universities of China:FRF-MP-20-43Z(JSH),FRF-TP-22-130A1(ZXB),FRF-TP-22-001C2(WY).
文摘Precipitation of multiple strong nanoprecipitates is crucial for the development of ultrahigh-strength structural materials with a strength of 2.5 GPa or above.Nevertheless,the ductility usually loses rapidly with strength due to limited dislocation mobility and high cracking tendency if coarse non-deformable precipitates are employed.Herein,we report a 2.5 GPa maraging steel strengthened by an ultrahigh den-sity of intermeshed shearable nanostructures consisting of Ni(Al,Fe)nanoprecipitates and Mo-rich(∼30 at.%)disordered clusters,both of which assume coherent interfaces.The fully coherent B2-Ni(Al,Fe)par-ticles precipitate in an extremely fast fashion,effectively accelerating local aggregation of low-diffusivity Mo atoms and promoting the formation of Mo-rich clusters surrounding them.This elemental partition was found to be further enhanced by Co addition via depleting both residual Al and Mo within the ma-trix,leading to the formation of copious yet fine intermeshed nanostructures.During plastic deformation,the interlocked nanostructures not only enhance local cutting stress by combining long-range elastic and short-range chemically ordering effects but also improve dislocation activity and resist shear-induced plastic instability.The multiple shearable nanostructures endow decent ductility(>6%)of the 2.5 GPa steel,suggesting a new paradigm for designing ultrastrong steels.
基金supported by the National Key R&D Program of China under grant No.2018YFA0404703the Open Project Program of the Key Laboratory of FAST,NAOC,Chinese Academy of Sciences。
文摘The Phased Array Feed(PAF)is considered as one of the next generation receivers for radio telescopes,which can significantly enlarge the instantaneous Field-of-View of large aperture single dish radio telescopes and enable more flexible observing configurations.Study efforts on PAF development for radio telescopes have been made for more than two decades and have become more and more applicable.We report the development of an ambient-temperature 19 element L-band PAF system and the experimental results including its far field beam pattern and system temperature measurement,which achieve the expectations.Implementing the aperture array beam-forming method,we demonstrate a wide-field Galactic HI observations in the radio camera mode.The results indicate that this system might be applicable for strong Galactic transient detections.This system could be directly equipped to large telescopes like the Five-hundred-meter Aperture Spherical radio Telescope(FAST)and FAST array in the future.
