Kinetic limit for incubation period of primary phase produced by the combination reaction between two solid heterogeneous pure metals

Abstract

An irreversible thermodynamics model was constructed to study the combination reaction of two heterogeneous pure metals in diffusion bonding based on the theorem of minimum entropy production and the Curie principle. The correlation between the irreversible reaction and diffusion was discussed, which provided the kinetic inevitability of an incubation period of a primary phase. The analytical descriptions of the incubation period and the kinetically critical grain size of the primary phase were deduced. Comparison of the experimental results of Al/Mo interfacial reaction with the calculations indicated that the performed theoretical analysis was reliable.incubation period, primary phase, interfacial reaction, irreversible thermodynamics A solid-solid interfacial reaction (SSIR) of two heterogeneous pure metals at constant temperature and pressure is an essential process in many material processing applications, such as diffusion bonding of different metals, preparation of metal matrix composites and powder metallurgy processing [1][2][3] . Therefore, a deep understanding of SSIR mechanism is necessary for precise control of the above-mentioned applications. However, many details about this mechanism are still unclear, except for a few guiding principles.Generally, the approach to theoretical study of the SSIR is based on classical thermodynamics [4][5][6][7][8] . However, these theories, even though being applicable to equilibrium state, can hardly achieve satisfying answers to time-dependent problems. For example, on the questions of primary