ABSTRACTTwo complementary experimental techniques are presented that describe the mechanisms during the combustion synthesis of NiAl and Ti5Si3. The first involves quenching a reacting wedge-shaped sample imbedded in a copper block where the propagating combustion front extinguishes while traveling to the apex. The second technique, time-resolved X-ray diffraction (TRXRD), provides a direct in-situ observation of the sequence of high temperature phase transformations. The information obtained from this investigation will be useful in developing improved process models of combustion synthesis, which can lead to the production of advanced materials with tailored microstructure and properties.