Formation of Al-Fe-Si glass that grows from the melt through a first-order transition

► Microstructures of rapidly solidified Al-Fe-Si alloys demonstrate formation of a glassy phase, which we term q-glass, that is not a kinetically frozen liquid. ► The phase grows from the melt by a first order phase transition in the manner of a crystal, but scatters as a metallic glass. ► In this paper, by studying a large number of Al-Fe-Si alloys (8-22 at% Fe and 5-20 at% Si), we confirmed this observation and identified domains of formation of the q-glass, as well as a 1/1 α-cubic approximant and an icosahedral phase.