Single Crystallization Mechanism in TLP Bonded Interlayer of Single Crystal Superalloy

摘要

The crystallographic orientation analysis over the bonded region in transient liquid phase (TLP) bonded joints of Ni-base single crystal superalloy, CMSX-2 was investigated using MBF-80 insert metal. TLP bonding of CMSX-2 was carried out at 1173 approx 1573 K for 0 approx 19.6 ks in vacuum. The (001) orientation of each test specimen was always aligned perpendicular to the joint interface. The (200)-pole figure and the stereographic triangles for three directions using the electron back scattering pattern (EBSP) method indicated that each analyzed point was projected at the almost same location for any directions. For as-bonded and post-bond heat treated specimens, all analyzed points possessed the almost same orientation across the joint interface and misorientation was negligibly small. HRTEM observation revealed that the atoms were arranged continuously across the bonded interface and quite coherent at the bonded interface. It was confirmed that epitaxial growth of the solid phase occurred from the base metal substrates during isothermal solidification and single crystallization could be achieved.