Table of Contents Author Guidelines Submit a Manuscript
Advances in Materials Science and Engineering
Volume 2014, Article ID 639461, 8 pages
http://dx.doi.org/10.1155/2014/639461
Research Article

Mechanical Properties and Thermal Stability of TiN/Ta Multilayer Film Deposited by Ion Beam Assisted Deposition

1Wuhan Research Institute of Materials Protection, Wuhan 430030, China
2State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China

Received 1 May 2013; Accepted 24 October 2013; Published 28 January 2014

Academic Editor: Aiguo Xu

Copyright © 2014 Hongfei Shang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

TiN/Ta multilayer film with a modulation period of 5.6 nm and modulation ratio of 1 : 1 was produced by ion beam assisted deposition. Microstructure of the as-deposited TiN/Ta multilayer film was observed by transmission electron microscopy and mechanical properties were investigated. Residual stress in the TiN/Ta multilayer film was about 72% of that of a TiN monolayer film with equivalent thickness deposited under the same conditions. Partial residual stress was released in the Ta sublayers during deposition, which led to the decrease of the residual stress of the TiN/Ta multilayer film. Nanohardness (H) of the TiN/Ta multilayer film was 24 GPa, 14% higher than that of the TiN monolayer film. It is suggested that the increase of the nanohardness is due to the introduction of the Ta layers which restrained the growth of TiN crystal and led to the decrease of the grain size. A significant increase (3.5 times) of the / (E elastic modulus) value indicated that the TiN/Ta multilayer film has higher elasticity than the TiN monolayer film. The (critical load in nano-scratch test) value of the TiN monolayer film was 45 mN, which was far lower than that of the TiN/Ta multilayer film (around 75 mN). Results of the indentation test showed a higher fracture toughness of the TiN/Ta multilayer film than that of the TiN monolayer film. Results of differential scanning calorimetric (DSC) and thermo gravimetric analysis (TGA) indicate that the TiN/Ta multilayer film has better thermal stability than the TiN monolayer film.