Proceedings of the 43rd International Field Emission Symposium
J. Phys. IV France 06 (1996) C5-253-C5-258
Atom-Probe Field-Ion Microscopy Investigation of CMSX-4 Ni-Base Superalloy Laser Beam WeldsS.S. Babu1, S.A. David2, J.M. Vitek2 and M.K. Miller2
1 Pennsylvania State University, PA 16802.
2 Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6096, U.S.A.
CMSX-4 superalloy laser beam welds were investigated by transmission electron microscopy and atom probe field-ion microscopy (APFIM). The weld microstructure consisted of fine (10- to 50-nm) irregularly shaped γ' precipitates (0.65 to 0.75 volume fraction) within the γ matrix. APFIM compositions of the γ and γ' phases were found to be different from those in the base metal. Concentration profiles across the γ and γ' phases showed extensive variations of Cr, Co and Al concentrations as a function of distance within the γ phase. Calculated lattice misfits near the γ interface in the welds are positive values compared to the negative values for base metal.
© EDP Sciences 1996