Castability of Cu54Ni6Zr22Ti18 bulk amorphous alloy

Abstract

Castability, in a narrow sense, means the formability of a particular liquid metal into a desired shape by transformation from liquid to solid. Considering the importance of recycling, the reuse of returned scrap should be related to castability. In addition, glass forming ability should also be studied for bulk amorphous metals, as it is very closely related to crack formation during casting. This paper reports a study on the castability of Cu-base bulk amorphous alloy made by conventional vacuum induction melting. The effects of specimen thickness, number of remeltings, and mold temperature were investigated. A test mold for thin plate specimens was designed in order to evaluate the liquid formability of the alloy. Mold filling was good for 2 mm specimens; however, many cracks were observed after cooling. While the mold cavities were not fully filled for 1 mm specimens, no cracks could be found. The glass forming ability also became worse with increasing number of remeltings; this worsening is believed to be caused by the increase in oxygen content.

Correlation of microstructure and tensile properties of Ti-based amorphous matrix composites modified from conventional titanium alloys

“…However, the manufacturing cost is still high because of the relatively high expense of alloying elements and the requirement of a vacuum environment during casting, and the size and shape of the fabricated products are restricted. In addition, they have poor ductility and toughness because of brittle fractures due to highly localized shear bands [7,8]. If the fabrication method of amorphous alloys by utilizing conventionally used alloys such as the Ti-6Al-4V alloy and by forming a sufficient amount of ductile dendrites in the amorphous matrix can be developed, the aforementioned disadvantages can be solved.…”