SPEAKER PROFILE |
 Dr. Nicholas Randall Vice President Business Development Alemnis AG Switzerland |
Recent innovation in the field of in-situ micro and nanoscale mechanical testing
Abstract
Since emerging in the early 1990s, nanoindentation has established itself as a routine technique for mechanical property measurements, offering a very high degree of flexibility and applicability. It has been used to study the entire spectrum of materials including metals, ceramics, polymers, composites and biomaterials. This talk will introduce in-situ Scanning Electron Microscope (SEM) nanomechanical testing, which was pioneered by Alemnis AG, showing how the technique has evolved in recent years and how recent innovations have allowed new mechanical properties to be evaluated.
Nanomechanical tests are moving beyond the basic measurement of hardness and elastic modulus to encompass a host of different mechanical properties such as strain rate sensitivity, stress relaxation, creep, and fracture toughness by taking advantage of focused ion beam milled geometries. New developments, such as high cycle fatigue, are extending the range of properties which can be studied at the micro and nanoscale. However, such techniques are challenging due to low oscillation frequencies, long duration of tests and large thermal drift when attempted with standard indentation instruments. Novel piezo-based nanoindentation methods are now allowing access to extremely high strain rates (>104 s-1) and high oscillation frequencies (up to 10 kHz).
Other recent innovations include cryogenic and high temperature tests covering the temperature envelope from -150 to 800 °C. The challenges in variable temperature tests and the associated technological and protocol advances will be discussed along with select case studies. The inherent advantages of using small volumes of sample material, e.g., small ion beam milled pillars, will be discussed together with the associated instrumentation, technique development, data analysis methodology and experimental protocols. Finally, future research directions in this sub-field of micromechanics will be discussed.
Acknowledgements: InnoSuisse is acknowledged for providing funding for HYSEMMEC and FASTOBS projects..
Dr. Randall has published extensively in the field of surface mechanical properties testing. He is chairman of ASTM committee G02.40, responsible for developing tribological test standards for non-abrasive wear. He has been teaching for over 25 years and has authored over 70 scientific publications.
Nanomechanical tests are moving beyond the basic measurement of hardness and elastic modulus to encompass a host of different mechanical properties such as strain rate sensitivity, stress relaxation, creep, and fracture toughness by taking advantage of focused ion beam milled geometries. New developments, such as high cycle fatigue, are extending the range of properties which can be studied at the micro and nanoscale. However, such techniques are challenging due to low oscillation frequencies, long duration of tests and large thermal drift when attempted with standard indentation instruments. Novel piezo-based nanoindentation methods are now allowing access to extremely high strain rates (>104 s-1) and high oscillation frequencies (up to 10 kHz).
Other recent innovations include cryogenic and high temperature tests covering the temperature envelope from -150 to 800 °C. The challenges in variable temperature tests and the associated technological and protocol advances will be discussed along with select case studies. The inherent advantages of using small volumes of sample material, e.g., small ion beam milled pillars, will be discussed together with the associated instrumentation, technique development, data analysis methodology and experimental protocols. Finally, future research directions in this sub-field of micromechanics will be discussed.
Acknowledgements: InnoSuisse is acknowledged for providing funding for HYSEMMEC and FASTOBS projects..
Bio
Dr. Nicholas Randall is a Chartered Engineer (CEng MIM) and holds a B.Sc. in Materials Science from Brunel University (London, UK) 1994 and a Ph.D. from Neuchatel University (Neuchatel, Switzerland) 1997. He studied nanoscale tribological phenomena during his PhD thesis. During his time with CSM Instruments (1997-2013) he served as Customer Services Manager and then Vice-President Business Development whilst setting up the US subsidiary. He was then Lead Scientist with Anton Paar Tritec, following the acquisition of CSM Instruments by Anton Paar in 2013. He is currently Vice-President Business Development with Alemnis, a company specialized in in-situ micromechanical testing.Dr. Randall has published extensively in the field of surface mechanical properties testing. He is chairman of ASTM committee G02.40, responsible for developing tribological test standards for non-abrasive wear. He has been teaching for over 25 years and has authored over 70 scientific publications.