SYNTHESIS OF AN AMORPHOUS ZR-AL-NI-CU ALLOY WITH LARGE SUPERCOOLED LIQUID REGION BY COLD-ROLLING OF ELEMENTAL FOILS

Amorphous samples of a multicomponent Zr-Al-Ni-Cu alloy with a large s upercooled liquid region of 98 K have been synthesized at ambient temp erature from a layered array of individual elemental sheets by repeate d low strain rate cold-rolling with intermediate folding. The alloying reactions during cold-rolling were monitored with electron microscopy , X-ray diffraction and thermal analysis. During the initial stage of processing a dissolution of solute into Zr along with a reduction in g rain size to about 30 nm was observed and with further processing a fu lly amorphous sample was obtained after 120 deformation cycles. The ch aracteristics of the amorphous phase developed by repeated cold deform ation indicate that it is compositionally homogeneous, structurally mo re relaxed as compared to mechanically alloyed amorphous powders of si milar composition and without the typical impurity levels obtained by mechanical alloying. (C) 1998 Acta Metallurgica Inc. Published by Else vier Science Ltd. All rights reserved.