Impact of low-energy mechanical activation of powder mixture and subsequent heating mode on the physical and mechanical properties of intermetallic compound Ni3Al

Abstract

The influence of preliminary low-energy mechanical activation (LEMA) of the 3Ni + Al powder mixture on the grain structure, porosity, microhardness, plasticity, and hardness of the Ni₃Al intermetallic compound was investigated using experimental and theoretical methods. The heating of the mechanically activated mixture was conducted in two modes: continuous heating with an external energy source and heating with its shutdown at near-critical low temperatures. It was found that preliminary LEMA facilitates the synthesis of an intermetallic compound with a fine-grained structure (∼3 μm). Additionally, LEMA increases porosity by 26 %, hardness by 15–33 %, and microhardness by 87.5 %, while reducing plasticity by 16.2 %. It was demonstrated that early deactivation of the external heat source during the heating of the LEMA-treated mixture does not significantly affect the formation of the single-phase product or its physicochemical properties. This finding suggests the potential for significant energy savings in the synthesis of Ni₃Al. Analytical relationships were derived to estimate the hardness and grain size of Ni₃Al synthesized from the LEMA-treated mixture.