Zhang Zhihao  Liu Xinhua   Xie Jianxin

(School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083)

Abstract: Bulk metallic glass (BMG) is one of the important research results of material science in recent years, which has many excellent properties compared with other metallic engineering materials. Because of the excellent super-plasticity in super-cooled liquid region of BMG, it is very hopeful to fabricate precision amorphous metallic parts with complicated configuration through plastic working processes. Using Zr41.25Ti13.75Ni10Cu12.5Be22.5 bulk metallic glass rods of 5 mm diameter, fine spur gear with boss (pitch diameter 6 mm, number of gear teeth 24, modulus 0.25 mm) is fabricated with super-plastic die-forging method under vacuum condition. The forming results of different processes such as hole-forming by upper-mandrel, hole-forming by bottom-mandrel and two-stage forming are analyzed. The results show that the two-stage hole-forming process has lower forming pressure and decentralization level of inner hole. The fine spur gear with good size-precision and surface-roughness is obtained through two-stage hole-forming process scheme and reasonable die structure design. XRD shows that the fabricated parts have no obvious crystallization, the excellent properties of as-cast Zr41.25Ti13.75Ni10Cu12.5Be22.5 bulk metallic glass being kept.

Key words: Bulk metallic glass  Super-plasticity  Precision spur gear

CLC No: TG306

国家863计划(2003AA305600)和国家杰出青年科学基金(50125415)资助项目. Received 20040315, received in revised form 20040930