Unusual macroscopic shearing patterns observed in metals processed by high-pressure torsion
Unusual macroscopic shearing patterns observed in metals processed by high-pressure torsion
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DOI：
10.1007/s10853-010-4485-5
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发表时间：
2010-09-01
影响因子：
4.5
通讯作者：
Langdon, T. G.
中科院分区：
文献类型：
--
作者：
Cao, Y.;Kawasaki, M.;Langdon, T. G.
对双相不锈钢进行了高压扭转（HPT）加工，并进行了光学显微镜观察。结果表明，不寻常的流动模式，包括双旋流应变，剪切涡，并存在显着的局部湍流。在高纯度铝和Zn-22%Al共析合金的圆盘中也可见类似的流动行为。这些复杂的流动模式和双旋流的存在与HPT处理过程中Kelvin-Helmholtz不稳定性的存在一致，如果HPT盘内相邻位置之间存在局部剪切速度梯度，则可能出现这种情况。
A duplex stainless steel was processed by high-pressure torsion (HPT) and then examined by optical microscopy. The results reveal unusual flow patterns including double-swirl strains, shear vortices, and the presence of significant local turbulence. Similar flow behavior was also visible in disks of high-purity aluminum and a Zn-22%Al eutectoid alloy. These complex flow patterns and the presence of double-swirls are consistent with the presence of a Kelvin-Helmholtz instability during HPT processing where this may arise if there are local shear velocity gradients between adjacent positions within the HPT disks.