Nature and growth of interaction layer formed during the reaction between solid Ni and liquid Al

The nature and growth of the interaction layer between solid Nb and liquid Al were studied by carrying out the tests on Nb(s)-Al(l) and Nb(s)-Al(l)-Ni(s) reaction couples isothermally reacted 700°C-900°C for different time intervals. It was found that the interaction layer between Nb and Al contains two parts: a thin continuous layer of NbAl3 adjacent to the Nb surface and a two-phase zone composed of NbAl3 particles dispersed in an Al matrix. Although the nature and growth of the interaction layer follows the four-stage mechanism, a typical cruciform pattern does not occur in the Nb(s)-Al(l) reaction couple. However, a cruciform pattern was observed in the Nb(s)-Al(l)-Ni(s) reaction couple. The movement of NbAl3 particles is important to the production of the cruciform pattern in the reaction couples.