The micro-formability of Zr-based amorphous alloys in the supercooled liquid state and their application to micro-dies

Zr-based amorphous alloys exhibit an obvious glass transition phenomenon an d supercooled liquid state over a wide temperature range. In the present pa per, the authors study the macroscopic and microscopic deformation behavior of Zr-Al-Cu and Zr-Al-Cu-Ni amorphous alloys. On a macroscopic scale, the materials exhibit a Newtonian viscous flow in the supercooled liquid state. To evaluate the microformability of the materials, the authors developed a n evaluation system using a micro-V-grooved die made of (1 0 0) silicon tha t has been processed by electron beam lithography and anisotropic etching a nd employed this system to quantitatively evaluate the microscopic formabil ity of the materials. The V-groove is from 1 to 20 mum wide and has a base angle of 70.6 degrees. The material was subjected to the newly developed mi cro-forging apparatus and was die forged with micro-V-grooved dies. After t he deformation, the shape of the specimen was measured using a three-dimens ional shape measurement system with a highly sensitive detector in a scanni ng electron microscope. These geometrical analyses of deformed specimens co nfirmed the superior formability on a micrometer scale and indicated the po ssibility of fabricating very fine micro-parts such as those for micro-elec tro-mechanical systems (MEMS). Furthermore, the material is stable under th e glass transition temperature T-g, and can thus be used as a fine micro-fo rging die for some plastic materials or other amorphous alloys with a glass transition temperature below T-g. In the present paper, it was confirmed t hat Zr-Al-Cu amorphous alloy could be used as a micro-die for forming La-Al -Ni amorphous alloy. As a result, it was demonstrated that amorphous alloys are potential micro-materials for fabricating various micro-parts or micro -dies because of their superior mechanical characteristics and homogeneity on a microscopic scale. (C) 2001 Elsevier Science B.V. Ah rights reserved.