Plastic strain-induced phase transformations in silicon: drastic reduction of transformation pressures, change in transformation sequence, and particle size effect
Plastic strain-induced phase transformations in silicon: drastic reduction of transformation pressures, change in transformation sequence, and particle size effect
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发表时间：
2023-03
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通讯作者：
Sorb Yesudhas;V. Levitas;F. Lin;K. Pandey;Jesse D. Smith
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作者：
Sorb Yesudhas;V. Levitas;F. Lin;K. Pandey;Jesse D. Smith
作为最重要的电子材料，硅的多个相之间的压力诱导相变(PTS)已经被研究了几十年。对于塑性应变诱发的PTS来说，情况并非如此。在这里，我们在原位揭示了各种意想不到的塑性应变诱导的PT现象。因此，对于100 nm的Si，应变诱导的PT Si-I到Si-II(以及Si-I到Si-III)在流体静力条件下的起始压力分别为0.4 Gpa(0.6 Gpa)和16.2 Gpa(因为没有发生应变诱导)；对于30 nm的Si，应变诱导的PT Si-I和Si-II的应变诱导起始压力分别为6.1 Gpa和16.2 Gpa。对于Si-II的出现，证实了晶粒度对屈服强度的正逆Hall-Petch效应与应变诱导PT的最小压力之间的理论关联。实现了在常压下保留Si-II并获得与Si-I PT相反的Si-II，展示了操纵不同合成路线的可能性。
Pressure-induced phase transformations (PTs) between numerous phases of Si, the most important electronic material, have been studied for decades. This is not the case for plastic strain-induced PTs. Here, we revealed in-situ various unexpected plastic strain-induced PT phenomena. Thus, for 100 nm Si, strain-induced PT Si-I to Si-II (and Si-I to Si-III) initiates at 0.4 GPa (0.6 GPa) versus 16.2 GPa ($\infty$, since it does not occur) under hydrostatic conditions; for 30 nm Si, it is 6.1 GPa versus $\infty$. The predicted theoretical correlation between the direct and inverse Hall-Petch effect of the grain size on the yield strength and the minimum pressure for strain-induced PT is confirmed for the appearance of Si-II. Retaining Si-II at ambient pressure and obtaining reverse Si-II to Si-I PT are achieved, demonstrating the possibilities of manipulating different synthetic paths.