micromachines Review Low Temperature Nanoindentation: Development and Applications Shunbo Wang 1 and Hongwei Zhao 1,2,* 1 School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China;
[email protected] 2 Key Laboratory of CNC Equipment Reliability, Ministry of Education, Changchun 130025, China * Correspondence:
[email protected]; Tel.: +86-0431-85095757 Received: 15 March 2020; Accepted: 30 March 2020; Published: 13 April 2020 Abstract: Nanoindentation technique at low temperatures have developed from initial micro-hardness driving method at a single temperature to modern depth-sensing indentation (DSI) method with variable temperatures over the last three decades. The technique and implementation of representative cooling systems adopted on the indentation apparatuses are discussed in detail here, with particular emphasis on pros and cons of combination with indentation technique. To obtain accurate nanoindentation curves and calculated results of material properties, several influence factors have been carefully considered and eliminated, including thermal drift and temperature induced influence on indenter and specimen. Finally, we further show some applications on typical materials and discuss the perspectives related to low temperature nanoindentation technique. Keywords: low temperature; nanoindentation; hardness test; apparatus; mechanical properties 1. Introduction Nanoindentation technique has become one of the most popular mechanical property testing methods in recent years [1–5]. Compared with uniaxial tension and compression tests, the specimen requirements of nanoindentation were more simplified: a flat, no shape required surface. The mechanical properties, including but not limited to hardness and elastic modulus, can be obtained automatically via commercial system using Hertz contact theory [6] and Oliver-Pharr analysis method [7].