On Interface Formation in Zr-Based BMG/6061 Al Interconnects Joined by μFSSW

摘要

Bulk metallic glasses (BMGs) are very attractive to a range of microelectronic applications including sensing elements, precision optics, and micro-geared motors due to their high strength, elasticity, corrosion resistance, and soft magnetic properties. Although joining BMGs to dissimilar materials to manufacture interconnects for micro-electronic devices is a great challenge, micro-friction stir spot welding (μFSSW) is a novel solid-state joining process which makes it a strong candidate for joining BMGs or BMGs to other crystalline materials to fabricate various types of interconnects. However, studies on the dissimilar μFSSW of BMGs to aluminum (Al) alloys are limited. This paper presents experimental investigations on interface formation in μFSSW of dissimilar Zr-based BMGs (i.e. LM105) to 6061 Al alloys. A series of μFSSW of dissimilar 1.5 mm thick LM105 BMGs-to-6061Al-T6 sheets trials were conducted and the stir zone temperature was measured. The obtained joint cross sections were characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and the effect of μFSSW conditions on the joint interface's microstructure evolution was evaluated. It has been found that the BMGs materials were stirred into the Al side in the stir zone and reacted with the Al to form the Al-rich phase.