Single-Crystallization Behavior in TLP-Bonded Interlayer: Transient Liquid Phase Bonding of Ni-Base Single Crystal Superalloy (Report 6)

Crystallographic orientation analysis over the bonded region in TLP-bonded joints of Ni-base single crystal superalloy, CMSX-2 was investigated three-dimensionally using the electron back scattering pattern (EBSP) method. The (200)-pole figure and the stereographic triangles for three directions indicated that each analyzed point was projected at the almost same location in the stereographic triangles for any directions. EBSP analyses for the specimen bonded at 1523 K for 1.8 ks when the isothermal solidification was complete, and for the specimen post-bond heat-treated were also conducted. All analyzed points possessed the almost same orientation across the joint interface and misorientation OB was negligibly small in as-bonded and post-bond heat-treated situations. HRTEM observation revealed that the atoms were arranged continuously across the bonded interface and were quite coherent at the bonded interface. It was confirmed that single-crystallization could be readily achieved during TLP-bonding. It followed that epitaxial growth of the solid phase occurred from the base metal substrates during isothermal solidification.