Determination of Time-Dependent Plastic Properties of Metals by Indentation Load Relaxation Techniques

Abstract

AbstractLoad relaxation testing has been demonstrated to be useful for characterizing the time dependent plastic properties of metals. However, for testing of small material volumes, such as thin film metallizations, thin films, and contact surfaces, conventional load relaxation techniques cannot be used. For such applications an indentation test offers an attractive means for obtaining data necessary for materials characterization. This work shows that an indentation load relaxation test is experimentally feasible for thin film testing. Experiments on brass and beryllium copper samples with or without a gold/nickel plating illustrate different relaxation properties of the substrates and the surface layers. Furthermore, results of experiments on some fcc metals suggest rather simple relations between the conventional uniaxial load relaxation (LR) test and the indentation load relaxation (ILR) test.