The void nucleation mechanism within lead phase during spallation of leaded brass |
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| Authors: | Yang Yang Can Wang Xingzhi Chen Kaiguo Chen Haibo Hu Yanan Fu |
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| Institution: | 1. School of Material Science and Engineering, Central South University , Changsha, China;2. Institute of Fluid Physics, China Academy of Engineering Physics , Mianyang, China;3. Key Laboratory of Nonferrous Metals Material Science and Engineering of Ministry of Education, Central South University , Changsha, China;4. School of Material Science and Engineering, Central South University , Changsha, China;5. Institute of Fluid Physics, China Academy of Engineering Physics , Mianyang, China;6. Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai, China |
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| Abstract: | The incipient spall behaviours of Cu-34%Zn-3%Pb leaded brass samples with annealed and cryogenic-treated conditions were loaded using one-stage light gas gun experiments. The effect of Pb-phase on dynamic damage nucleation in leaded brass specimens was investigated by means of optical microscopy, scanning electron microscopy and x-ray computer tomography. It was found that the voids of incipient spall were mainly nucleated in the interior of the lead (no tensile stress would be produced within lead according to the impact theory) instead of nucleated at the phase interface as expected by quasi-static damage fracture theory. A nucleation model is proposed in the present work that is the asymmetry high compression zones in the centre of the lead-phase were formed by the rarefaction wave convergence effects of matrix/quasi-spherical lead interface, which caused adiabatic temperature rise that exceeded melting point of lead due to severe plastic deformation, finally led to local melting and void nucleation. In addition, the spall strength and damage rate increased with the increase in the Pb-phase number. |
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| Keywords: | Spall void nucleation cryogenic treatment x-ray computer tomography leaded brass |
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