EBSD and XRM of phases in vacuum cast composite alloys

There have been a number of new processes developed that allow the joining of very dissimilar materials such as titanium alloys, wear resistant white irons, cast irons and ceramic materials to ferrous (mild steel) and non-ferrous (aluminium) alloys. These new processes have allowed the development of more complex composite shapes to be produced. However, with any new process development, an understanding of the mechanism of bonding is required. Through the use of x-ray mapping (XRM), chemical phase imaging as well as electron back scattered diffraction (EBSD) analysis, very useful information on the mass transport across the interface as well as phase segregation, texture variations and phase distribution within the bond interface can be obtained. Results from this investigation on a number of bonded materials are presented and the importance of XRM and EBSD in providing a better understanding of the physical and chemical processes involved in metallurgical bonding/welding of dissimilar materials discussed.