Fatigue testing is the process of measuring the failure limit of a material when subjected to stress such as repeated axial loading or bending. Fatigue testing detects progressive localized permanent structural change occurring in a material subjected to conditions that produce fluctuating stresses and strains at some point or points and that may culminate in cracks or complete fracture after a sufficient number of fluctuations. Fatigue testing is commonly performed by axial loading or in bending, thus producing tensile and compressive stresses. The stress is usually cycled in some way, either in a constant manner or in increasing intensity until the failure limit is attained.

Indentation fatigue test on a MEMS beam
Fatigue test graph

Indentation fatigue test on a MEMS beam using cyclic incremental loading until failure

The Alemnis Standard Assembly (ASA) can be used to perform standard nanoindentation fatigue tests (typically at low oscillation frequencies) or high frequency oscillatory fatigue tests with the Ultra High Strain (UHSR) option. The flexibility of the system allows fatigue testing to be performed in many sample orientations and configurations. Examples include quasi-static uniaxial indentation, high frequency indentation fatigue, beam bending, micropillar compression fatigue, impact fatigue, etc.

Fatigue test at high frequency

Simulation of a capacitive accelerometer stopper damaged by shock at high frequency

The Alemnis Standard Assembly (ASA) is designed for high and low frequency fatigue tests.

The Alemnis Standard Assembly (ASA) can be mounted in-situ in any Scanning Electron Microscope (SEM). The ASA can also be mounted ex-situ at any angle, depending on how it is mounted with a complimentary technique, e.g., vertically for synchrotron beam line.

Main Components:

  • Displacement head: piezo actuated displacement head with integrated displacement sensor for closed loop operation. Maximum displacement 40 µm, displacement resolution < 1 nm;
  • Load sensor: max. force: 0.5 N, typically 4 µN RMS noise;
  • Sample versus indentation tip positioning: Piezoelectric XY+Z micro-positioning system for sample positioning and tip approach (26 mm range in X and Y, 26 mm range in Z), with integrated position sensors for closed loop operation (< 2 nm resolution);
  • 5 standard stubs;
  • all cables and connectors for in air operation.