The nanoindenter at the AMMC is an innovative nanomechanical testing platform (Micro Materials Ltd: NanoTest Xtreme) with a nanoscale positioning stage sitting on the anti-vibration table inside a vacuum chamber. It not only allows for quasi-static indentation testing at room temperature but also enables the analysis to be performed at low (- 40⁰C) and high (up to 800⁰C) temperatures using the elaborately designed sample stages.
The instrument has the capacity of operating at the maximum 500 mN load at a thermal drift rate below 0.01 nm/s. The nano-impact and fatigue module to be delivered will enable the analysis of impact resistance, dynamic hardness and low cycle fatigue, providing complementary information to nanoindentation. The analysis can be carried out at the maximum static load of 100 mN with the maximum acceleration distance of 18 µm and a strain rate up to 103 s-1.
The graph to the upper right shows two indentation curves from a steel sample at room temperature, where a discontinuity (also called the ‘pop-in’ event) in the measured depth can be seen in the blue curve. The observation of a sudden burst of displacement signifies the occurrence of plastic deformation such as dislocation nucleation or phase transformation. The figure to the right below is a scanning electron microscope (SEM) image of four typical indentation imprints that are 20 µm apart. (Courtesy of M. Ghasri Khouzani, C. Slater and C. Davis)
Contact: Fengzai (Frank) Tang Fengzai dot Tang at warwick dot ac dot uk , Samuel Marks S dot Marks at warwick dot ac dot uk and Geoff West G dot West at warwick dot ac dot uk