Effect of Preliminary Treatment on Microstructure, Mechanical Properties and Fracture of Ni3Al Samples Synthesized by Spark Plasma Sintering

A comparative study of microstructure parameters and mechanical property characteristics of consolidated Ni3Al samples formed by spark plasma sintering after a preliminary short-term mechanical activation and mixing in a mortar is carried out. It is found out that the grain size of the mechanically pre-activated material is several times smaller than that of the material sintered after mixing in a mortar. This feature is manifested in the differences in the values of microhardness and short-term strength. The annealing temperature effect on the structure parameters and mechanical properties of Ni3Al samples is revealed depending on the pretreatment. It is assumed that the formation of a high-defect structural state, characterized by fine grains combined with an increased level of microdistortions, during mechanical activation predetermines the strength properties of the material both after spark plasma sintering and after deformation and heat treatment.