Size dependent strengthening in high strength nanotwinned Al/Ti multilayers
Size dependent strengthening in high strength nanotwinned Al/Ti multilayers
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DOI：
10.1016/j.actamat.2019.06.028
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发表时间：
2019-06
期刊：
影响因子：
9.4
通讯作者：
Y.F. Zhang;S. Xue;Q. Li;Jin Li;Jie Ding;T. Niu;R. Su;H. Wang;X. Zhang
中科院分区：
文献类型：
--
作者：
Y.F. Zhang;S. Xue;Q. Li;Jin Li;Jie Ding;T. Niu;R. Su;H. Wang;X. Zhang
金属多层膜的机械行为已得到深入研究。在这里，我们报告了磁控溅射具有不同单层厚度（h=1-90nm）的高织构Al/Ti多层薄膜的研究。 Al/Ti 多层膜的硬度随着层厚度的减小而单调增加而不会软化，并超过 7GPa，使其成为迄今为止报道的最强的轻质多层系统之一。高分辨率透射电子显微镜和 X 射线衍射极图分析证实了 Al 层中高密度纳米孪晶和 9R 相的形成。纳米孪晶和堆垛层错的密度与单层厚度成反比。此外，当h≤4.5nm时，Ti发生HCP-FCC相变。 Al/Ti多层膜的高强度主要源于非共格层界面、高密度孪晶界以及堆垛层错。
Mechanical behavior of metallic multilayers has been intensively investigated. Here we report on the study of magnetron-sputtered highly textured Al/Ti multilayer films with various individual layer thicknesses (h = 1–90 nm). The hardness of Al/Ti multilayers increases monotonically with decreasing layer thickness without softening and exceeds 7 GPa, making it one of the strongest light-weight multilayer systems reported to date. High-resolution transmission electron microscopy and X-ray diffraction pole figure analyses confirm the formation of high-density nanotwins and 9R phases in Al layers. The density of nanotwins and stacking faults scales inversely with individual layer thickness. In addition, there is an HCP-to-FCC phase transformation of Ti when h ≤ 4.5 nm. The high strength of Al/Ti multilayers primarily originates from incoherent layer interfaces, high-density twin boundaries, as well as stacking faults.