The recrystallization behavior of ultra-high purity aluminum (99.999%) during tube high-pressure shearing (t-HPS) was studied at the average strain rate of 0.2s-1 and 1.2s-1 respectively. The microstructure after t-HPS was characterized by electron backscatter diffraction (EBSD). Different recrystallization behavior at different strain rate of t-HPS was observed by the distinct microstructure evolution. The results showed that at higher strain rate, a finer grain size and higher recrystallization fraction were obtained. While the difference of recrystallization fraction between higher and lower strain rate decreased with increasing strain level. It has the potential for producing gradient materials as there is a grain size gradient along the direction of shear plane normal (SPN) which is more pronounce at strain level of ε=5.8.
Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.
The potential of scaling up the industrial applications of the Equal Channel Angular Pressing using large square billets (d=32 mm and 12 mm) was investigated by experiment on oxygen-free high-conductivity (OFHC) copper. The microstructure of the intermediate deformation zone between zero-pass and one-pass of ECAP was characterized by EBSD, and the distribution of microhardness was also given to analyze the deformation region. The results show the width of inhomogeneous deformation zone is proportionate to sample size. The texture evolution during first pass of ECAP was investigated, and ideal components of simple shear textures were developed. After multi-pass of ECAP there was no obvious difference of microstructures (TEM) and mechanical properties between them. Strain and strain rate distributions were given by experiments. It is found that changing the absolute size of the sample does not change strain distribution in the deformation zone significantly, and so to the strain rate distribution when the absolute pressing speed changes proportionally to the sample size.
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