Reaction kinetics studies on Ti-Al-Cr-Nb-B intermetallics

摘要

In reaction synthesis (RS) route of powder metallurgy, heat of reaction between elemental powders is utilised to obtain intermetallic compounds. Prior to reaction synthesis of quaternary alloy Ti48Al2Cr2Nb (with 10 at. % B), reaction kinetics studies were carried out. Powder mixture was prepared and Differential Scanning Calorimetry (DSC) experiments were carried out at 3 different heating rates. Activation energy and Avrami Index ‘n’ are obtained by Johnson-Mehl-Avrami (JMA) equation. Formation of Al₃Ti was confirmed through X-ray diffraction (XRD). Reaction mechanisms are identified in accordance with ‘n’ values. In the temperature range of 1060–1150K, it proceeds as instantaneous nucleation and three dimensional growth with an activation energy of 176 kJ mole−1.