Nanoindentation characterisation of the properties around reinforcements in a heat treated spray deposited 2014+15vol%sSiCp metal-matrix composite

Abstract

The aging behavior of the metal-matrix composites (MMCs) with heat treatable matrix alloys has received many attentions and investigations. Usually, it was observed that the addition of the reinforcement components accelerates the aging kinetics of the composite materials compared to their control alloys. In recent years, the nanoindentation technique has gained widespread use for the determination of mechanical properties of thin films and nanomaterials. The nanoindentation has a displacement resolution of 0.16 nm and a load resolution of 0.3 {micro}N, allowing precise measurement of the depth h and load w, so that the mechanical properties of surface layers of bulk materials and of thin films adhesive to their substrate can be determined under essentially compressive conditions. Analysis of the load-displacement curves provides information not only on the hardness, but also on the elastic and creep properties of the films. In contrast to conventional hardness measurements, the nanoindentation technique furnishes a continuous record of both load and indentation depth during loading and unloading, so that imaging of the indentation is no longer required, and a much smaller area is involved in the measurement. All these features will be beneficial to the study of the properties around the reinforcements in a compositemore » material, and overcoming the shortcomings pointed out above for the study of the aging behavior of composite materials by the conventional microhardness measurements. However, studies on this subject were in rare cases reported in the literature. In this study, the authors try to apply the nanoindentation technique to study the aging behavior of an aluminium alloy 2014 reinforced with 15vol%SiC particulate, and to determine the micromechanisms for the aging behavior of the composite.« less