Combustion Synthesis of Fe-Cu-TiC Composites under Electric Field

Fe-Cu-TiC composites were synthesized and consolidated simultaneously at an ignition temperature of 759 °C by electric field-assisted combustion synthesis (EFACS). This electric field was generated by a Gleeble thermal simulation instrument. The combustion synthesis process of 15(Ti+C)-65Fe-20Cu (wt%) system, where the molar ratio of Ti to C was 1:1, was studied according to quenching at different temperatures. A four-step model was proposed to describe the combustion synthesis process of Fe-Cu-TiC composites under an electric field. It is suggested that EFACS consists of preheating (I), solid diffusion (II), combustion (III), and post-combustion (IV) stages. The solid diffusion of reactant atoms increases with temperature increasing from the stage I to the stage II. From the stage II to the stage III, carbon atoms gradually diffuse towards titanium atoms until their close contact is performed. During the initial stage III, Ti starts to react with C, i.e. Ti(s) +C(s) =TiC(s) at their interfaces and TiC surrounds the raw Ti atom. Moreover, liquid Cu is formed at the same time. In the following stage III, C atoms diffuse further through the reactant TiC layer, and full reaction between C and Ti is accomplished. The nucleation and growth of TiC takes place in the stage IV. As can be seen from the SEM photographs, TiC exhibits spherical particle.