The details of the special three-dimensional micro-nano scale ripples with a period of hundreds of microns on the surfaces of a Zr-based and a La-based metallic glass irradiated separately by single laser pulse are in...The details of the special three-dimensional micro-nano scale ripples with a period of hundreds of microns on the surfaces of a Zr-based and a La-based metallic glass irradiated separately by single laser pulse are investigated.We use the small-amplitude capillary wave theory to unveil the ripple formation mechanism through considering each of the molten metallic glasses as an incompressible viscous fluid.A generalized model is presented to describe the special morphology,which fits the experimental result well.It is also revealed that the viscosity brings about the biggest effect on the monotone decreasing nature of the amplitude and the wavelength of the surface ripples.The greater the viscosity is,the shorter the amplitude and the wavelength are.展开更多
Zr 52 Cu 18 Ni 15 Al 10 Ti 5 bulk glass samples with a diameter of 8 mm prepared by copper mold with water cooling have a mixing structure of amorphous phase and quenched in crystals. By isothermal annealing at differ...Zr 52 Cu 18 Ni 15 Al 10 Ti 5 bulk glass samples with a diameter of 8 mm prepared by copper mold with water cooling have a mixing structure of amorphous phase and quenched in crystals. By isothermal annealing at different temperatures, the crystallization process of the glass alloy is shown to be a multi staged crystallization reaction as follows: Am+quenched in crystals→Am′+cellular phase+(Zr, Ti) Al→Am′+cellular phase+(Zr, Ti) Al+(Zr, Ti) 2(Cu, Ni). Morphology of the quenched in crystals changes from dot or dendritic phase in the as cast bulk glass to cellular phase at different annealing states. The residual region surrounded by the cellular phase has a mixing structure of nano scale phase and amorphous phase.展开更多
The electrical properties of proton ion beam irradiated glass samples are carried out by impedance spectroscopy in the frequency range from 10 Hz to 32 MHz. The ion beam of energy 3 MeV and fluence of of 1014 particle...The electrical properties of proton ion beam irradiated glass samples are carried out by impedance spectroscopy in the frequency range from 10 Hz to 32 MHz. The ion beam of energy 3 MeV and fluence of of 1014 particles cm-2 was chosen for irradiation. The conductivity of the super ionic glass samples increases after irradiation and other electrical parameters like dielectric constant, dielectric loss and modulus of the proton irradiated glass samples as a function of glass composition and temperature are observed to change. The dielectric constant and the dielectric losses are increased after irradiation and the modulus parameters confirm the non-Debye nature for irradiated samples also.展开更多
Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabr...Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabricated. The parameters like bird dimension and energy requirements are accordingly scaled to conduct the bird strike tests. Two leading-edge components have been prepared, namely one with AL 2024-T3 aluminium alloy and the other specimen of the same dimension and material, additionally having GF-SMP composite layers inside the metallic leading edge, in order to enhance its impact resistance. Bird strike experiments are performed on both the specimens, impacting at the centre of the leading edge in the nose tip region with an impact velocity of 115 m/s. The test component is instrumented with linear post-yield strain gauges on the top side and the PZT sensors on the bottom. Furthermore, the impact scenario is monitored using a high-speed camera at 7000 fps. The bird strike event is simulated by an equation of state model, in which the mass of the bird is idealized using smooth particle hydrodynamics element in PAMCRASH<sup>?</sup><sup> </sup>explicit solver. The strain magnitude and its pattern including time duration are found to be in a good correlation between test and simulation. Key metrics are evaluated to devise an SHM scheme for the load and impact event monitoring using strain gauges and PZT sensors. GF-SMP layers have improved the impact resistance of the aluminium leading edge which is certainly encouraging towards finding a novel solution for the high-velocity impact.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10572002,10732010,and 11332002)
文摘The details of the special three-dimensional micro-nano scale ripples with a period of hundreds of microns on the surfaces of a Zr-based and a La-based metallic glass irradiated separately by single laser pulse are investigated.We use the small-amplitude capillary wave theory to unveil the ripple formation mechanism through considering each of the molten metallic glasses as an incompressible viscous fluid.A generalized model is presented to describe the special morphology,which fits the experimental result well.It is also revealed that the viscosity brings about the biggest effect on the monotone decreasing nature of the amplitude and the wavelength of the surface ripples.The greater the viscosity is,the shorter the amplitude and the wavelength are.
文摘Zr 52 Cu 18 Ni 15 Al 10 Ti 5 bulk glass samples with a diameter of 8 mm prepared by copper mold with water cooling have a mixing structure of amorphous phase and quenched in crystals. By isothermal annealing at different temperatures, the crystallization process of the glass alloy is shown to be a multi staged crystallization reaction as follows: Am+quenched in crystals→Am′+cellular phase+(Zr, Ti) Al→Am′+cellular phase+(Zr, Ti) Al+(Zr, Ti) 2(Cu, Ni). Morphology of the quenched in crystals changes from dot or dendritic phase in the as cast bulk glass to cellular phase at different annealing states. The residual region surrounded by the cellular phase has a mixing structure of nano scale phase and amorphous phase.
文摘The electrical properties of proton ion beam irradiated glass samples are carried out by impedance spectroscopy in the frequency range from 10 Hz to 32 MHz. The ion beam of energy 3 MeV and fluence of of 1014 particles cm-2 was chosen for irradiation. The conductivity of the super ionic glass samples increases after irradiation and other electrical parameters like dielectric constant, dielectric loss and modulus of the proton irradiated glass samples as a function of glass composition and temperature are observed to change. The dielectric constant and the dielectric losses are increased after irradiation and the modulus parameters confirm the non-Debye nature for irradiated samples also.
文摘Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabricated. The parameters like bird dimension and energy requirements are accordingly scaled to conduct the bird strike tests. Two leading-edge components have been prepared, namely one with AL 2024-T3 aluminium alloy and the other specimen of the same dimension and material, additionally having GF-SMP composite layers inside the metallic leading edge, in order to enhance its impact resistance. Bird strike experiments are performed on both the specimens, impacting at the centre of the leading edge in the nose tip region with an impact velocity of 115 m/s. The test component is instrumented with linear post-yield strain gauges on the top side and the PZT sensors on the bottom. Furthermore, the impact scenario is monitored using a high-speed camera at 7000 fps. The bird strike event is simulated by an equation of state model, in which the mass of the bird is idealized using smooth particle hydrodynamics element in PAMCRASH<sup>?</sup><sup> </sup>explicit solver. The strain magnitude and its pattern including time duration are found to be in a good correlation between test and simulation. Key metrics are evaluated to devise an SHM scheme for the load and impact event monitoring using strain gauges and PZT sensors. GF-SMP layers have improved the impact resistance of the aluminium leading edge which is certainly encouraging towards finding a novel solution for the high-velocity impact.
