Formation of chromium borides in quenched

The beneficial effect of boron on the mechanical properties of austenitic stainless steels is well documented [1, 2]. A number of studies have confirmed that boron segregates to grain boundaries, in a variety of steels and nickel-base alloys (for example, [3, 4, 5]). Segregation of boron is known to occur via two mechanisms (for example, [1]): Equilibrium segregation is caused by the high binding energy for boron at grain boundaries and other defects. This effect decreases with increasing temperature and depends strongly on the grain boundary structure. Non-equilibrium segregation is caused by the dissociation of boron-vacancy complexes near the grain boundary which acts as a vacancy sink. In this case, the segregation effect increases as the starting temperature increases, and is believed to depend little on the nature of the grain boundary, as most are believed to be efficient vacancy sinks [6] (with the exception of twin boundaries, along which boron segregation is not observed).