The effect of temperature and strain rate on the hardness of Al and Al-based foams as measured by nanoindentation

In this work, we have used a nanoindentation system inside a temperature ch amber to investigate the time- and temperature-dependent deformation behavi or of the cell walls in an Al-based foam. Constant indentation strain rates were used to study the deformation behavior between room temperature and 1 00 degreesC. The depth-sensing indentation experiments were significantly i nfluenced by a very strong, nonlinear thermal drift. Nevertheless. it was p ossible to measure the hardness as a function of indentation depth by measu ring dynamically the contact stiffness and assuming a constant indentation modulus for the tested material. In summary, it was found that the hardness of the Al foam is twice as high as of pure Al, and the hardness decreases with increasing temperature and decreasing strain rate, following a power-l aw dependence.