Structure and Properties of an Ni₃Al Intermetallic Compound Formed as a Result of Spark Plasma Sintering of the Powder Mixtures Prepared by Various Methods

The paper described the structure and mechanical properties of nickel aluminide (Ni₃Al) obtained by spark plasma sintering of the two compositions of nickel and aluminum powder mixtures with and without the addition of 0.1 wt.% boron, as well as with and without mechanical activation of such mixtures. It was found that by introducing a small amount of boron, it becomes possible to achieve a more beneficial effect on the relative density (98.8%) and strength properties of sintered nickel aluminide compared to the mechanical activation of the initial powders. The addition of boron to a mechanically activated powder mixture of nickel and aluminum (composition: 3Ni + Al) contributes to the formation of a work-piece with the highest complex of strength properties. The ultimate flexural strength (2,200 MPa) of the obtained material is 2.8 times higher than that of the material having the same composition, but without boron additives. The tensile strength (970 MPa) increases by 2.4 times. The level of impact toughness of the sintered nickel aluminide with boron additive increases by a factor of 5.