Abstract
Minor additions of Sn in the bulk glass-forming Fe61−xSnxY2Zr8Co5Cr2Mo7B15 (x =
0% to 2%) system were studied in detail. It was found that combinations of Y and Sn
can scavenge oxygen out of the undercooled liquids to form innocuous oxides, thus
stabilizing the liquids. Besides this beneficial scavenging effect, Sn additions in the
present Fe-based alloys also showed complex alloying effects on glass formation,
which can be divided into three stages. At stage I (x 0.5%), the microalloyed
compositions associate with the same eutectic as that of the base alloy. The
glass-forming ability (GFA) of the resulting alloys is determined primarily by their
liquidus temperature and similar to that of the base alloy. At stage II (0.85% x
1.15%), glass-matrix composite structures start to form because the alloy compositions
are adjusted into a new “deeper” eutectic system. At stage III (x > 1.15%), however,
alloy compositions shift to another new eutectic system, and the GFA is dramatically
decreased due to the strong formation of primary phase –Fe. Homogeneous
glass-matrix composites with a diameter of 7 mm in the alloy containing 1.0–1.15% Sn
were successfully produced.