Experimental Study of Thermal and Flame Front Characteristics in Combustion Synthesis of Porous Ni-Ti Intermetallic Material

This article describes experimental investigation of thermal and combustion phenomena during the self-propagating combustion synthesis of Ni-Ti intermetallic materials for structural application. Ni-Ti mixture is prepared from elemental powders of Ni and Ti. The mixture is pressed into solid cylindrical samples of 1.1-cm diameter and 2-3-cm length, with initial porosity ranging from 30 to 42%. The samples are preheated to various initial temperatures and ignited from the top surface such that the flame propagates axially downward. The flame speed images are recorded with a motion camera, and the temperature profile is recorded. The flame front propagation velocity is deduced as a function of the preheat temperature and initial porosity as well as the effective thermal conductivity of the reactants.