In-situ investigation of microcrack formation and strains in Ag-Cu-based multi-metal matrix composites analysed by synchrotron radiation

In this study, multi-metal matrix composites based on SiC fibres coated with titanium alloys are investigated. In contrast to ordinary titanium matrix composites, the consolidation was realised by an infiltration process using a silver-based filler material in order to avoid shrinkage, distortion or fibre breakage. During the infiltration process, a transition zone between the titanium coating and the filler material developed consisting of several intermetallic phases. The behaviour of this intermetallic reaction zone under stepwise increased tensile stresses was investigated in-situ by synchrotron radiation using computer tomography and X-ray diffraction. Multiple cracks were observed already at the lowest investigated load level. Depending on the titanium alloy, different types of fracture occurred within the intermetallic transition zones with limited elastic strains in the predominant intermetallic phase TiCu.