緩慢壓縮的高熵合金納米柱中的位錯雪崩機制

論文標題：Dislocation avalanche mechanism in slowly compressed high entropy alloy nanopillars

作者：Yang Hu, Li Shu, Qun Yang, Wei Guo, Peter K. Liaw, Karin A. Dahmen, Jian-Min Zuo

數字識別碼： 10.1038/s42005-018-0062-z

最近《通訊-物理學》發表的一項研究Dislocation avalanche mechanism in slowly compressed high entropy alloy nanopillars通過將電子成像和機械測量結合起來研究位錯雪崩機制。

晶體會因位錯的間歇性增殖和滑移雪崩而變形。位錯增殖已經被研究的比較清楚，但是雪崩背後的形成機制尚不清楚，而且缺乏普適性的論點導致了關於晶體塑性有很多「細節混亂且具爭議」的意見。

來自伊利諾伊大學香檳分校材料科學與工程學系的Jian-Min Zuo及其研究團隊，他們通過直接的電子成像技術和精確的機械測量手段，跟蹤了高熵合金Al0.1CoCrFeNi壓縮納米柱中的位錯雪崩進程。結果表明，雪崩起始於位錯堆積和位錯帶的形成。位錯堆積形成在位錯帶前面，它的釋放會觸發雪崩，就像打開了一道水閘門。納米柱中位錯雪崩的大小在幾納米到100納米之間，其冪律分布類似於地震。因此，該研究識別了大晶體滑移的位錯相互作用機制，並對高熵合金的變形提供了關鍵性見解。

打開今日頭條，查看更多圖片

圖1：納米柱壓縮實驗設計

摘要：Crystals deform by the intermittent multiplication and slip avalanches of dislocations. While dislocation multiplication is well-understood, how the avalanches form, however, is not clear, and the lack of insight in general has contributed to 「a mass of details and controversy」 about crystal plasticity. Here, we follow the development of dislocation avalanches in the compressed nanopillars of a high entropy alloy, Al0.1CoCrFeNi, using direct electron imaging and precise mechanical measurements. Results show that the avalanche starts with dislocation accumulations and the formation of dislocation bands. Dislocation pileups form in front of the dislocation bands, whose giveaway trigs the avalanche, like the opening of a floodgate. The size of dislocation avalanches ranges from few to 102 nm in the nanopillars, with the power-law distribution similar to earthquakes. Thus, our study identifies the dislocation interaction mechanism for large crystal slips, and provides critical insights into the deformation of high entropy alloys.

閱讀論文全文請訪問：http://t.cn/E422UNz

期刊介紹：Communications Physics(https://www.nature.com/commsphys/) is an open access journal from Nature Research publishing high-quality research, reviews and commentary in all areas of physics. Research papers published by the journal represent significant advances bringing new insight to a specialized area of research.

（來源：Communications Physics ）

喜歡這篇文章嗎？立刻分享出去讓更多人知道吧！