Microscopic view of structural phase transitions induced by shock waves
Microscopic view of structural phase transitions induced by shock waves
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DOI：
10.1126/science.1070375
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发表时间：
2002-05-31
期刊：
影响因子：
56.9
通讯作者：
Holian, BL
中科院分区：
文献类型：
--
作者：
Kadau, K;Germann, TC;Holian, BL
数百万原子分子动力学模拟用于研究冲击引起的固体铁相变。在临界冲击强度之上，许多小的密堆积晶粒在冲击压缩的体心立方晶体中成核，在皮秒时间尺度上生长，形成更大的、能量上有利的晶粒。在该阈值上方立即观察到分裂的两波冲击结构，弹性前兆位于滞后转换波之前。为了获得更高的冲击强度，可以获得单一的超驱动波。发展中的密堆积晶粒的动力学和取向取决于冲击强度，尤其是晶体冲击方向。未冲击区域和冲击区域之间的取向关系类似于铁及其合金中温度驱动的马氏体转变中发现的取向关系。
Multimillion-atom molecular-dynamics simulations are used to investigate the shock-induced phase transformation of solid iron. Above a critical shock strength, many small close-packed grains nucleate in the shock-compressed body-centered cubic crystal growing on a picosecond time scale to form larger, energetically favored grains. A split two-wave shock structure is observed immediately above this threshold, with an elastic precursor ahead of the lagging transformation wave. For even higher shock strengths, a single, overdriven wave is obtained. The dynamics and orientation of the developing close-packed grains depend on the shock strength and especially on the crystallographic shock direction. Orientational relations between the unshocked and shocked regions are similar to those found for the temperature-driven martensitic transformation in iron and its alloys.