NUMERICAL-ANALYSIS FOR MICROPYRETIC SYNTHESIS OF NIAL INTERMETALLIC COMPOUND

A numerical investigation of the micropyretic synthesis response parameters of the Ni-Al stoichiometric compound was undertaken. The influence of the enthalpy of the combustion reaction, Q, activation energy, E, amount of diluent, pre-exponential factor, K-0, and initial temperature T-0, on the combustion velocity, temperature, and mode was studied. The porosity of the unreacted compact, which is related to the initial compaction pressure, was considered in the calculation. It was found that the change in porosity significantly affects the thermal conductivity and the length of the pre-heat zone as also do the temperature patterns and propagation velocities. The combustion front was noted to be extinguished if the temperature in the reaction zone became tower than the melting point of the aluminium phase. This result was obtained simply by considering the changes in the thermal conductivity after the melting of aluminium without having to invoke any changes in the rate of reaction after the melting. A comparison of the numerical data with the experimental and analytical results was also made.