Microchemistry studies of ductile L1₂ Ni-based intermetallics

Auger electron microscopy (AES) analysis of boron doped Ni₃Al have shown boron segregation at grain boundary (GB). Boron segregation was enhanced with increasing bulk boron content independent of stoichiometry, suggesting that hypo-stoichiometric alloy is intrinsically ductile even without boron. A slight Ni cosegregation is confirmed using atom probe field ion microscope (APFIM). In Ni₃(Si,Ti), no distinct composition fluctuation was identified between matrix and GB vicinity. These results suggest that atomic bonding atmosphere modification from covalent to metallic in the vicinity of GB is one of factors to modify ductility for L1₂-type intermetallics.