Crystallisation of oxygen-stabilised amorphous phase in a Zr50Cu50 alloy

The crystallisation of the oxygen-stabilised amorphous phase in a Zr50Cu50 alloy has been investigated by means of neutron diffraction and electron mi croscopy. The crystallisation microstructure consists of ZrO2, Zr2Cu and-Zr 7Cu10. A two-stage crystallisation mechanism is suggested: (i) primary crys tallisation of Zr2Cu and (ii) formation of nanocrystals ZrO2 and Zr7Cu10. I n (i), it is proposed Zr2Cu crystallises from the oxygen-stabilised amorpho us phase, leaving an oxygen- and copper-enriched matrix; Zr2Cu rapidly grow s and eventually attains a grain size of about 100 nm. In (ii), it is sugge sted, the residual amorphous matrix crystallises into nanocrystals ZrO2 and Zr7Cu10 due to the sluggish growth of ZrO2 and to the already formed ZrO2 which acts as a growth barrier to Zr7Cu10. In this case there is no particu lar orientation relationship between Zr2Cu and Zr7Cu10. (C) 2001 Elsevier S cience Ltd. All rights reserved.