Abstract
To realize combustion synthesis process of intermetallic compound, a method of fabricating of full dense compound should be developed. In my previous paper, synthesis of Ni3Al intermetallic compound by pressureless combustion synthesis process was investigated. Consequently, it was found that density of the synthesized compound depended on initial powder particle size, and the nearly full dense product was obtained in case of using fine powders as initial substances. The densification might be caused by combustion temperature, compound formation ratio, quantities of liquid phases during the synthesis. However the details is not clear, to evolve the process, the cause of the densification and a course for producing the full dense compound should be established. In this paper, numerical analysis of the combustion synthesis of Ni3Al was performed as a continuation of the previous investigation, and the cause of densification was analyzed.
A Ni/Al premixed compact during thermal explosion combustion synthesis was divided into infinite elements, numerical analysis model was derived under consideration of heat balance and material balance equations around the elements. The model was solved by I. A. D. method, the combustion synthesis behavior was analyzed.
The compound formation behavior during the combustion synthesis was able to be simulated. The maximum combustion temperature or the ratio of compound formation at the each temperature during the synthesis did not depend on the powder particle sizes. However, the quantities of the liquid phases was greatly affected by the sizes, and it was guessed that the liquids is the cause of the densification. The quantities of the liquids were able to be increased by control of beginning temperature of the combustion, heat injection to the compact and enlargement of the compact size. Therefore, these countermeasures might be effective to synthesize the dense compound.
