A comparative study on the influence of different manufacturing methods(selective laser melting and hot rolling)on the microstructure,mechanical and thermal behaviours of tungsten(W)was presented for the first time.Th...A comparative study on the influence of different manufacturing methods(selective laser melting and hot rolling)on the microstructure,mechanical and thermal behaviours of tungsten(W)was presented for the first time.The results indicated that the selective laser melting(SLM)W exhibited a finer grain sizes,a lower strength ductility,hardness and thermal conductivity compared to hot-rolled W.The main reason for this result was that the laser underwent rapid heating and cooling when it was used to melt W powder with high energy density,resulting in large internal stress in the sample after manufacturing.Subsequently,the internal stress was released,leading to the generation of microcracks at the grain boundaries,thereby affecting the performance of SLM W samples.In addition,the higher fraction of high-angle grain boundaries(HAGBs)of SLM W was found to be the key factor for intrinsic brittleness.Because the HAGBs are the preferred crack paths,which could promote crack propagation and decrease fracture energy.展开更多
Excellent fluid sealing performance is crucial to ensuring the safety of important equipment,especially in aerospace field,such as space capsule and fuel chamber.The frequently opening and closing of the sealing devic...Excellent fluid sealing performance is crucial to ensuring the safety of important equipment,especially in aerospace field,such as space capsule and fuel chamber.The frequently opening and closing of the sealing devices is particularly important.Driven by this background,clams(Mactra chinensis)which can open and close their double shells with superior sealing performance,are studied in this work.Here,we show that the clam’s sealing ability is the result of its unique multilevel intermeshing microstructures,including hinge teeth and micro-blocks.These microstructures,which resemble gear teeth,engage with each other when the shell closes,forming a tight structure that prevents the infiltration of water from the outside.Furthermore,the presence of micron blocks prevents the penetration of finer liquids.The simulation results of the bionic end seal components show that the multilevel microstructure has a superior sealing effect.This research is expected to be applied to undersea vehicles that require frequent door opening and closing.展开更多
基金National Natural Science Foundation of China(Grant No.U1808216)Hubei Provincial Natural Science Foundation of China(Grant No.2020CFB667)+2 种基金Hubei Provincial Key Research and Development Program of China(Grant No.2020BAB045)Wuhan Second Ship Design and Research Institute(No.YT19201903)the Sixth China Association of Science and Technology Youth Talents Invitation Project(No.YESS20200326).
文摘A comparative study on the influence of different manufacturing methods(selective laser melting and hot rolling)on the microstructure,mechanical and thermal behaviours of tungsten(W)was presented for the first time.The results indicated that the selective laser melting(SLM)W exhibited a finer grain sizes,a lower strength ductility,hardness and thermal conductivity compared to hot-rolled W.The main reason for this result was that the laser underwent rapid heating and cooling when it was used to melt W powder with high energy density,resulting in large internal stress in the sample after manufacturing.Subsequently,the internal stress was released,leading to the generation of microcracks at the grain boundaries,thereby affecting the performance of SLM W samples.In addition,the higher fraction of high-angle grain boundaries(HAGBs)of SLM W was found to be the key factor for intrinsic brittleness.Because the HAGBs are the preferred crack paths,which could promote crack propagation and decrease fracture energy.
基金supported by the National Natural Science Foundation of China(52105296,51973165 and 62161160311)the Fundamental Research Funds for the Central Universities(2042022kf1220)+1 种基金Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(EMPI2023020)Large-scale Instrument And Equipment Sharing Foundation of Wuhan University.
文摘Excellent fluid sealing performance is crucial to ensuring the safety of important equipment,especially in aerospace field,such as space capsule and fuel chamber.The frequently opening and closing of the sealing devices is particularly important.Driven by this background,clams(Mactra chinensis)which can open and close their double shells with superior sealing performance,are studied in this work.Here,we show that the clam’s sealing ability is the result of its unique multilevel intermeshing microstructures,including hinge teeth and micro-blocks.These microstructures,which resemble gear teeth,engage with each other when the shell closes,forming a tight structure that prevents the infiltration of water from the outside.Furthermore,the presence of micron blocks prevents the penetration of finer liquids.The simulation results of the bionic end seal components show that the multilevel microstructure has a superior sealing effect.This research is expected to be applied to undersea vehicles that require frequent door opening and closing.
