Acoustic Emission Analysis of SCS-6 Fiber Fracture in Titanium Matrix Composites

Abstract

One aspect of successful composite design involves development of a detailed knowledge of damage evolution. In metal matrix composites, cracking and/or plastic deformation of one or more constituents together with fiber-matrix interfacial debonding and sliding generally occur prior to catastrophic failure [1, 2]. The nature and severity of these damage processes controls mechanical performance. In ductile matrix systems having a low fiber-matrix interfacial strength, the failure process can involve successive fragmentation of the fibers with increasing load. Broken fibers shed load (equally among the unbroken fibers in the case of global load sharing) until the fiber fracture density reaches some critical value and the sample catastrophically fails. Characterization of damage development has been slowed by a lack of NDE techniques. Here, the use of acoustic emission (AE) techniques is explored to further understand and quantify failure processes of this type.