Material Characterisation with New Indentation Technique Based on Laser-Induced Shockwaves

Abstract

Conventional material development of new compositions is expensive and time consuming. Thus, for material characterisation there is a demand to enable high through-put experimentation to analyse and develop new materials in a short time. In this context, a new experimentation method is presented, which is based on TEA CO2 laser-induced shockwaves. First, plasma is created with a nanosecond pulsed TEA CO2 laser on top of a spherical indenter. Further interactions of the plasma with the high intensity laser beam result in a shockwave. The pressure of the shockwave is used to force the indenter penetrate inside the test material. Indentations are created on different aluminium alloys and correlated with hardness. The influence of environmental conditions, indenter material and diameter are investigated. Additionally, an energy model is introduced, which describes the possible indentation strain energy in dependence of the indenter diameter and the shockwave energy transferred to the indenter. The experiments reveal that smaller indenter diameters are recommendable for higher impact efficiencies. Best indentation results are achieved in terms of reproducibility and depth with a 3 mm indenter.