Formation of the Ni3Al intermetallic compound grain structure in the nonequilibrium conditions of the initial elements interaction

Abstract

Investigation of the influence of preload on powder mixture 3Ni + Al and plastic deformation of high temperature synthesis product on grain size and strength properties of Ni3Al intermetallic compound synthesized in a unified cycle of volume exothermic reaction process of intermetallic compound formation under pressure were carried out. It is shown that during the process of high-temperature synthesis under pressure in obtained samples of the Ni3Al intermetallic compound an irregular structure (in grain size) is formed - the grain size increases from the upper surface of the synthesized sample to the central part of the cross-section, with following decrease to the lower surface. With the increase in the value of the preliminary pressure applied to the initial powder mixture, the average grain size in the bulk of the synthesized intermetallic sample decreases, on retention of general distribution of the disparate grains in the volume of the synthesized samples. The most effect of grain size reducing in the intermetallic compound synthesized under pressure is observed when the compacting process in a mold-reactor is combined with a partial extrusion of the high-temperature synthesis product. Change of the grain size has a significant effect on the strength and plasticity of the intermetallic compound Ni3Al. With the decreasing of Ni3Al intermetallic compound grain size, its strength and plasticity are increase.