Bulk Glassy and Quasicrystalline (Zr₆₅Al_7.5Cu_27.5)_100−xTi_x Alloys and Their Mechanical Properties

Abstract

The glass-forming ability (GFA) and thermal stability of (Zr₆₅Al_7.5Cu_27.5)_100−xTi_x (x=0∼15; in at%) alloys have been investigated. It was revealed that a certain amount of Ti addition could improve the GFA of Zr₆₅Al_7.5Cu_27.5 alloy effectively. The best bulk metallic glass (BMG) forming composition was found at (Zr₆₅Al_7.5Cu_27.5)₉₃Ti₇. Bulk glassy samples with diameter of 7 mm were made by means of copper mold casting. Further Ti additions deteriorated GFA and led to the precipitation of icosahedral phase, and 3 mm quasicrystalline cylinder was obtained at (Zr₆₅Al_7.5Cu_27.5)₉₀Ti₁₀. Room temperature compression testing showed that the quasicrystalline alloy had a fracture strength of 1875 MPa, being 300 MPa larger than that of the (Zr₆₅Al_7.5Cu_27.5)₉₃Ti₇ monolithic BMG.