Nanoindentation Properties of H T c Superconducting Single-Crystalline Whiskers
- PDF / 489,056 Bytes
- 5 Pages / 595.276 x 790.866 pts Page_size
- 50 Downloads / 223 Views
O R I G I N A L PA P E R
Nanoindentation Properties of HTc Superconducting Single-Crystalline Whiskers O. Kızılaslan · F. Yılmaz · M.A. Aksan · M.E. Yakıncı
Received: 6 November 2012 / Accepted: 30 November 2012 / Published online: 22 December 2012 © Springer Science+Business Media New York 2012
Abstract In this work, superconducting and mechanical properties of BSCCO superconducting whiskers were studied in detail. Nanoindentation properties of the whiskers were analyzed by the Oliver and Pharr Method and Work of Indentation (WI) method. More accurate results using the WI method for both the hardness and the reduced modulus were obtained due to reduction of the pile-up error. The correct hardness and reduced modulus values were determined by considering the indentation size effect and the substrate (epoxy resin) effect. The modified composite hardness model and the composite reduced modulus model are the most suitable models to investigate the nanoindentation properties of the whiskers. Keywords High-Tc superconductors · Elasticity · Nanoindentation
1 Introduction Recent technological developments require production and use of materials in the nano/micro scale. In 1989, the discovery of whisker growth in the high-Tc (HTc ) superconducting BiSrCaCuO (BSCCO) system has led to intensive studies on these materials [1]. Studies have been generally conducted to understand the optimum growth conditions of the superconducting whiskers and the superconducting properties O. Kızılaslan () · M.A. Aksan · M.E. Yakıncı Fen Edebiyat Fakultesi, Inonu Universitesi, Fizik Bolumu, 44280 Malatya, Turkey e-mail: [email protected] F. Yılmaz Fen Edebiyat Fakultesi, Gaziosmanpasa Universitesi, Fizik Bolumu, Tasliciftlik Kampusu, 60240 Tokat, Turkey
such as critical current density, Jc , and magnetic properties [2–5]. However, a few studies have been done on mechanical properties such as hardness, elastic modulus, fracture properties, and ductility. The superconducting materials generally show poor mechanical properties, such as extremely low ductility and high brittleness and, therefore, their practical applications are limited. Investigation of the mechanical properties of the superconducting whiskers is crucial for industrial applications. In recent decades, nanoindentation, also called as the depth sensing indentation, is widely used for characterization of the mechanical properties of solids [6–10]. This technique allows the determination of the mechanical properties at penetration depths as low as a few nanometer and at loads as small as a millinewton. Tests in small scale make this technique one of the inexorable tools to characterize mechanical properties of particularly thin films, coatings, and small volumes [11]. One of the most commonly used methods for estimating the mechanical properties of material is the Berkovich nanohardness test. In the present work, we investigated the hardness and the reduced modulus properties of BSCCO-based superconducting whiskers by using the nanoindentation technique. The most sui
Data Loading...
