Rules of plastic strain-induced phase transformations and nanostructure evolution under high-pressure and severe plastic flow
Rules of plastic strain-induced phase transformations and nanostructure evolution under high-pressure and severe plastic flow
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发表时间：
2023-05
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通讯作者：
F. Lin;V. Levitas;K. Pandey;Sorb Yesudhas;Changyong Park
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作者：
F. Lin;V. Levitas;K. Pandey;Sorb Yesudhas;Changyong Park
在金刚石对顶砧（DAC）中对强预变形Zr的非均匀压缩进行原位研究时，引入粗糙金刚石对顶砧（粗糙DA）来强化所有发生的过程。在{\alpha}-{\omega}相变（PT）过程中，Zr的晶粒尺寸和位错密度与压力、塑性应变张量和应变路径无关，仅取决于{\omega}-Zr的体积分数。粗糙-DA产生稳定的纳米结构在{\alpha}-Zr与较低的微晶尺寸和较大的位错密度比光滑-DA，导致的最小压力为{\alpha}-{\omega} PT的记录值0.67 GPa的两倍减少。应变诱导PT的动力学出乎意料地依赖于时间。
Rough diamond anvils (rough-DA) are introduced to intensify all occurring processes during an in-situ study of heterogeneous compression of strongly pre-deformed Zr in diamond anvil cell (DAC). Crystallite size and dislocation density of Zr are getting pressure-, plastic strain tensor- and strain-path-independent during {\alpha}-{\omega} phase transformation (PT) and depend solely on the volume fraction of {\omega}-Zr. Rough-DA produce a steady nanostructure in {\alpha}-Zr with lower crystallite size and larger dislocation density than smooth-DA, leading to a two-time reduction in a minimum pressure for {\alpha}-{\omega} PT to a record value 0.67 GPa. The kinetics of strain-induced PT unexpectedly depends on time.