Interaction of 18Cr-10Ni stainless steel with liquid aluminium

Abstract

The dissolution of an 18Cr-10Ni stainless steel in liquid aluminium at 700 to 850 ° C was found by the rotating disc technique to be non-selective and diffusion controlled. Experimentally determined values of the parameters characterizing the dissolution run are presented. In the case of saturated aluminium melts two intermetallic layers were found to form between the steel and the melt material at 700 °C. The compact layer adjacent to the steel surface is probably a solid solution based upon the Fe₂Al₅ compound. Its thickness,x, tends with increasing time to the limiting valuex _max = 10μm. The porous layer adjacent to the melt material is probably a solid solution based upon the FeAl₃ compound. After a certain period of non-linear growth its thickness,Y, increases with time,t, according to the linear law:Y = 1 × 10⁻⁸ t + 6 × 10⁻⁶ m. The time dependence of the total thickness of both layers is well described in terms of the “paralinear” kinetics. In the case of undersaturated aluminium melts the formation of a single-phase intermetallic layer, 3 to 11 μm thick, was observed at 700 ° C for 100 to 600 sec. The steel-to-aluminium transition joints with good mechanical properties were made by interaction of a solid steel material with liquid aluminium.