Reactive sintering of Ni(sub 3)Al intermetallic alloys under compressive stress

摘要

Synthesis of the Ni-25% at. Al intermetallic compound by the thermal explosion mode subject to the application of compressive stress was systematically investigated. The stress was applied prior to the reaction. It was proved that the compressive stress had a profound effect on the reaction, as well as the densification. At a relative low stress, a full reaction could be completed and the major phase of the final product is Ni(sub 3)Al. At higher stresses, a partial reaction was resulted and the final product was primary the intermediate phases, e.g. Ni and NiAl, etc. Three distinct reaction products were obtained in this study. When the stress was below approximately 5 MPa, a fully reacted product was obtained. Between 5 and 15 MPa, a fully and partially reacted zone coexisted. Above 15 MPa, only a partial reaction prevailed. In this experiment, a final product of 99.9% relative density was obtained at the high stress level.