Lattice parameter measurements had shown that boron was soluble in stoichiometric Ni3Al up to at least 1.12at% and that it produced a lattice strain of 0.13. Compression testing of large-grained stoichiometric Ni3Al alloys doped with different amounts of boron indicated a large lattice strengthening effect of 387MPa/at%. Transmission electron microscope observations revealed that boron concentrations above a certain level (in the range > 0.38at% but < 0.75at%) prevented superlattice-intrinsic stacking fault formation. However, no accompanying change in work-hardening rate (~5050MPa) was found, indicating that superlattice-intrinsic stacking faults contributed little resistance to plastic flow. The large change in strength per fractional change in lattice parameter due to boron additions (~3.76G), compared to other B-subgroup elements (~0.27G), suggested that boron produced an asymmetrical strain field.

The Effect of Boron on the Lattice Properties of Ni3Al. Baker, I., Huang, B., Schulson, E.M.: Acta Metallurgica, 1988, 36[3], 493-9