Adiabatic shearing behaviour of unweldable Al–Sc alloy under extremely high shear loading
Adiabatic shearing behaviour of unweldable Al–Sc alloy under extremely high shear loading
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DOI：
10.1179/026708309x12454008169384
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发表时间：
2010-06
影响因子：
1.8
通讯作者：
W. Lee;T.‐H. Chen;G. Lu
中科院分区：
文献类型：
--
作者：
W. Lee;T.‐H. Chen;G. Lu
本文采用压缩式分离式Hopkinson压杆研究了不可焊Al-Sc合金在3.0 × 105 ~ 6.3 × 105 s-1的高应变率下的绝热剪切行为。系统地研究了应变速率对不可焊铝钪合金的剪切应力、绝热剪切带特征和断裂特征的影响。结果表明，随着应变速率的增加，剪切应力和应变速率敏感性均增大。此外，它表明，绝热剪切带内形成的变形试样的所有值的应变速率。随着应变速率的增加，剪切带宽度减小，显微硬度增加。随着应变率的增加，剪切带附近的变形角和局部剪应变的大小都增加。当应变速率为3.0 × 105 s ~（-1）时，断口为多个穿晶断裂。当应变速率大于4.5 × 105 s-1时，断口呈现穿晶韧窝状特征，由此推断，随着应变速率的增加，不可焊Al-Sc合金的塑性提高。
The present study applies a compressive type split Hopkinson pressure bar to investigate the adiabatic shear behaviour of unweldable Al–Sc alloy under high strain rates ranging from 3·0 × 105 to 6·3 × 105 s–1. The effects of the strain rate on the shear stress, adiabatic shear band characteristics, and fracture features of the unweldable Al–Sc alloy are systematically examined. The results show that both the shear stress and the strain rate sensitivity increase with increasing the strain rate. In addition, it is shown that an adiabatic shear band is formed within the deformed specimens for all values of the strain rate. As the strain rate is increased, the width of the shear band decreases, but the microhardness increases. Moreover, the distortion angle and the magnitude of the local shear strain near the shear band both increase with increasing the strain rate. At a strain rate of 3·0 × 105 s–1, the fracture surface is characterised by multiple transgranular clearage fractures. However, for strain rates greater than 4·5 × 105 s–1, the fracture surface has a transgranular dimple-like characteristic, and thus it is inferred that the ductility of the unweldable Al–Sc alloy improves with increasing the strain rate.