Structure of the intermetallic compound Ni3Al synthesized under compression of the powder mixture of pure elements Part II: Influence of alloying by boron on the phase composition and the microstructure of grains of the mainphase

The Ni3B phase was formed when boron (0.5 at. pet B) was added to the inter metallic of stoichiometric and off-stoichiometric (Ni-24 at. pct Al) compou nds. In the alloy of stoichiometric composition the particles of Ni3B phase has the size around 0.1 mu m and is located on the grain boundary of the m ain phase. The decreasing of concentrations of Al in the off-stoichiometric alloy leads to increase in the degree of the long-range order parameter, i ncreasing the concentrations of boron in the solid solution and decreasing its localization on the grain boundary. Microalloying of boron leads to inc reasing in the fraction of grain monodomains with dislocations up to 0.7 in the alloy of the off-stoichiometric composition and up to 1 in the alloy o f the stoichiometric composition. It was established the correlation betwee n the degree of the concentration inhomogeneity, average density of the dis locations and the average long range-order parameter.