Crystallization of icosahedral AlMnSi

The crystallization characteristics of icosahedral (Al_0.786Mn_0214100−xSi_x were studied for x = 2, 4, and 6 using resistivity measurements, scanning calorimetry, electron microscopy and X-ray diffraction. We find that the first stage in the crystallization is the formation of the binary AlMn T phase even when the icosahedral phase contains silicon. As-spun ribbons of this composition invariably contain a small amount of f.c.c. aluminium which goes into solution concurrently with the formation of the T phase, producing a dramatic increase in the sample resistance, starting near 670 K. The final crystallization products are β-Al₉Mn₃Si and either λ-Al₄Mn, Al₆Mn or α-Al₉Mn₂Si_1.8, depending on the concentration of silicon in the sample.