Spiral fibers were considered to be an ideal toughening phase of ultra-high torsional release effect.In this work,ZrB_(2)(Z)-20 vol%SiC(S)spiral fiber(ZS_(sf))with controllable structure was prepared by a combination ...Spiral fibers were considered to be an ideal toughening phase of ultra-high torsional release effect.In this work,ZrB_(2)(Z)-20 vol%SiC(S)spiral fiber(ZS_(sf))with controllable structure was prepared by a combination approach of liquid rope effect and non-solvent-induced phase separation.Dominantly depended on the kinematic viscosity(η),dropping height(H),and flow rate(Q),the geometric parameters of ZS_(sf) involving filament diameter(d)and coil diameter(D)were followed the relationship of d≈0.516×10^(-3) Q^(1/2)H^(−1/4) and D≈0.25×10^(-3)(Q/H)^(1/3),respectively,within the optimizedηof 10-15 Pa·s.Three different microstructures of ZS_(sf) were achieved by adjusting the polymer/solvent/non-solvent system assisted with phase diagram calculation,including dense,hollow,and hierarchical pore structures.The ZrB_(2)-SiC with 1 wt%ZS_(sf) composites prepared by hot isostatic pressing(HIP)exhibited a~30%increase in fracture toughness(KIC,4.41 MPa·m^(1/2))compared with the ZrB_(2)-SiC composite,where the microscopic fracture toughness of the ZS_(sf) was~80%higher than that of the matrix.The fibers with a~10 nm in-situ-synthesized graphite phase amongst grain boundaries of ZrB_(2) and SiC changed the fracture mode,and promoted the crack deflection and pull-out adjacent the interface of matrix and the fiber.展开更多
基金supported by the Science and Technology Innovation Program of Shanghai in 2020 (Grant No.STCSM-20520714300)the National Natural Science Foundation of China (Grant No.U19A2099)+1 种基金National Major Science and Technology Projects of China (Grant No.J2019-VIII-0003-0165)Open Project of Shanghai Key Laboratory of Spacecraft Mechanism.
文摘Spiral fibers were considered to be an ideal toughening phase of ultra-high torsional release effect.In this work,ZrB_(2)(Z)-20 vol%SiC(S)spiral fiber(ZS_(sf))with controllable structure was prepared by a combination approach of liquid rope effect and non-solvent-induced phase separation.Dominantly depended on the kinematic viscosity(η),dropping height(H),and flow rate(Q),the geometric parameters of ZS_(sf) involving filament diameter(d)and coil diameter(D)were followed the relationship of d≈0.516×10^(-3) Q^(1/2)H^(−1/4) and D≈0.25×10^(-3)(Q/H)^(1/3),respectively,within the optimizedηof 10-15 Pa·s.Three different microstructures of ZS_(sf) were achieved by adjusting the polymer/solvent/non-solvent system assisted with phase diagram calculation,including dense,hollow,and hierarchical pore structures.The ZrB_(2)-SiC with 1 wt%ZS_(sf) composites prepared by hot isostatic pressing(HIP)exhibited a~30%increase in fracture toughness(KIC,4.41 MPa·m^(1/2))compared with the ZrB_(2)-SiC composite,where the microscopic fracture toughness of the ZS_(sf) was~80%higher than that of the matrix.The fibers with a~10 nm in-situ-synthesized graphite phase amongst grain boundaries of ZrB_(2) and SiC changed the fracture mode,and promoted the crack deflection and pull-out adjacent the interface of matrix and the fiber.
