AVS 66th International Symposium & Exhibition
    Thin Films Division Thursday Sessions
       Session TF-ThP

Paper TF-ThP31
Size Dependent Strengthening in High Strength Nanotwinned Al/Ti Multilayers

Thursday, October 24, 2019, 6:30 pm, Room Union Station B

Session: Thin Films Poster Session
Presenter: Yifan Zhang, Purdue University
Authors: Y. Zhang, Purdue University
S. Xue, Purdue University
Q. Li, Purdue University
J. Li, Purdue University
J. Ding, Purdue University
T.J. Niu, Purdue University
R.Z. Su, Purdue University
H. Wang, Purdue University
X. Zhang, Purdue University
Correspondent: Click to Email
Here we report on the study of magnetron-sputtered highly textured Al/Ti multilayers with various 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 (TEM) and X-ray diffraction pole figure analyses confirm the formation of high-density nanotwins and 9R phase 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. And the post-indentation TEM analysis reveals deformation induced phase transformation in Ti layer. The high strength of Al/Ti multilayers primarily originates from incoherent interface, high-density twin boundaries, as well as stacking faults. Our findings have general implication for the design of high-strength and light-weight heterogeneous nanocomposite materials.