Thermal stability and crystallization behavior of Al86Ni9Y5 amorphous alloys with different Si addition

In this paper, a series of (Al86Ni9Y5)100-xSix (x = 0, 1, 2, 3, 4, 5) amorphous ribbons were prepared to study the effect of Si addition on the crystallization behavior. The amorphous microstructure of Al86Ni9Y5 base alloy is essentially heterogeneous. When it is subjected to annealing, primary alpha-Al nanocrystals first precipitate in the Al -rich regions and then regrow in the residual amorphous matrix at a far higher temperature, resulting in two separate primary crystallization events, called as abnormal crystallization. Addition of Si to the base alloy principally enhances the chemical heterogeneity, due to which more alpha-Al crystals precipitates with a lower onset temperature and crystallization activation energy. Meanwhile this abnormal crystallization of alpha-Al is promoted when x <= 3. The largest temperature interval between two crystallization peaks of alpha-Al is up to 154 K. As more Si is added, however, the crystallization of Al3Ni and Al3Y is advanced, causing the vanishment of the abnormal crystallization. The strong interaction between different species of solute atoms and the existence of free Al atoms are responsible for the occurrence of the abnormal crystallization.

Automated summary

This paper investigates the effect of Si addition on the crystallization behavior by preparing a series of (Al86Ni9Y5)100-xSix (x = 0, 1, 2, 3, 4, 5) amorphous ribbons. The results show that Si addition enhances the chemical heterogeneity and promotes the abnormal crystallization of α-Al. However, with the increase of Si content, the crystallization of Al3Ni and Al3Y advances, leading to the disappearance of the abnormal crystallization.