Effect of impurities on adiabatic shear bands (ASB) formation and evolution in U-2.5 wt%Nb alloy under impact
| Autor: | Lifeng He, Tian Yang, Dongli Zou, Xianglin Chen, Piheng Chen, Ping Zhou, Dawu Xiao |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Nuclear and High Energy Physics
Materials science Alloy Nucleation 02 engineering and technology Split-Hopkinson pressure bar engineering.material 021001 nanoscience & nanotechnology 01 natural sciences 010305 fluids & plasmas Adiabatic shear band Shear (sheet metal) Condensed Matter::Materials Science Brittleness Nuclear Energy and Engineering 0103 physical sciences engineering Fracture (geology) General Materials Science Composite material 0210 nano-technology Stress concentration |
| Zdroj: | Journal of Nuclear Materials. 517:225-233 |
| ISSN: | 0022-3115 |
| Popis: | Local stress concentration sites and/or microstructural inhomogeneities result in the nucleation and initiation of adiabatic shear bands (ASB). This paper reports the influence of impurities for the initiation and evolution of ASBs in U-2.5 wt%Nb alloy. Both cylindrical specimen and hat-shaped specimen were used to investigate the formation and evolution mechanism of ASBs in U-2.5 wt%Nb alloy using a split Hopkinson pressure bar apparatus. It was observed that brittle inclusions such as carbides in all of the specimens break up to form microcracks at very small strain during impact, then the microcracks coalesce and grow with increasing strain, which revealed that the brittle impurities in specimen not only precedes adiabatic shear failure, but also likely to be a dominant micromechanical factor in the very generation of the band. Adiabatic shear fracture occurs in the top end of hat-shaped specimen, it also appears that the microstructural inhomogeneities play more important role in occurrence of ASBs than the geometrical inhomogeneities. Additionally, it was demonstrated that the ductile inclusion of niobium was susceptible to resist the propagation of shear bands. |
| Databáze: | OpenAIRE |
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