Synthesis and sintering of Ni 3Al intermetallic compound by combustion synthesis process

Abstract

In order to develop the production process of the Ni 3Al intermetallic compound, combustion synthesis of the Ni 3Al intermetallic compound was investigated. Some kinds of Ni and Al powders with differential powder size were used as initial substances. These powders were mixed, and the Ni/Al mixed compacts (Ni:Al = 3:1 in atomic ratio) were prepared. The compacts were heated in a vacuum furnace, and the Ni 3Al compound was produced by the thermal explosion combustion synthesis. For the compounds obtained, density measurement, microstructure observation, phase analysis, and strength test were performed. Furthermore, the combustion synthesis of the boron added Ni 3Al compound was investigated. The Ni, Al and B powders were mixed, and the boron added compacts were prepared. The combustion synthesis experiment was attempted as well. A nearly dense intermetallic compound could be obtained by controlling the raw powder size and the density of the green compact. The products consisted of the Ni 3Al grains of about 50 μm. From compressive test, it was found that the products obtained were equal to the compound produced by the fusion process. To improve brittle nature of the Ni 3Al compound, the synthesis of the boron added Ni 3Al was attempted. Although, the boron added compact fused during the combustion synthesis, the boron added compound could be synthesized by controlling the charge ratio of the Ni, Al and B powders. In the compressive test, plastic deformation was measured, and it was confirmed that the boron addition was effective to improve the brittle nature. The production process by the combustion synthesis route could be determined in this paper.