METALLIC GLASS-FORMATION AND PROPERTIES IN ZR AND TI ALLOYED WITH BE .1. BINARY ZR-BE-SYSTEM AND TI-BE-SYSTEM

Ultra-rapid liquid-quenching (> 105°C s-1) has been found to produce fully glass structures in the binary Zr-Be and Ti-Be alloy systems over composition ranges that bracket the respective eutectics Zr-34.5 at.%Be and Ti-37.5 at.%Be. Both systems also exhibit extended solubility of Be in the Zr and Ti b.c.c. terminal solid solutions. In addition, these studies revealed the existence of metastable ordered phases at 50 at.%Be in the two systems: m-ZrBe (orthorhombic Bf{hook}, CrB structure type) and m-TiBe (cubic B2, CsCl structure type). The experiments clearly indicate that critical cooling rates for glass formation in Ti-Be alloys are significantly higher than in Zr-Be alloys; consequently, only the Zr-Be glasses are readily fabricable in continuous ribbon form. Various criteria for establishing glass forming tendency (GFT) were examined and detailed calculations of critical cooling rates (Ṫ) using the Davies-Uhlmann kinetic formulations were carried out and compared with the experimental results. The composition dependences of certain physical properties of the glasses were also examined and are discussed. © 1979.