| Formation and growth of Widmansta¨tten HCP α phase in Mg-10wt%Li-3wt%Al has been investigated. Formation of Widmanstatten α phase has been investigated in detail by changing the cooling rate, i.e. by adopting the methods of water-quenching, air-cooling, and furnace-cooling. Growth of Widmansta¨tten α phase has been investigated by aging at 270℃. Widmansta¨tten type α phase becomes much finer with increasing cooling rate, resulting in higher hardness. The orientation relationship between Widmansta¨tten α phase precipitates and β phase matrix is:[21￣1]_α//[110]_β, (1￣11)_β//(101￣0)_α, Growth rate along the long axis of Widmanstatten α phase is 18.2㎛/hr. On the other hand, thickening rate is near zero, suggesting that ledges are not supplied sufficiently to the interface. |
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