The preparation and thermal and mechanical properties of new titanium rich metallic glasses

Abstract

The compositions of Ti-rich alloys in the TiNiSi system which form a metallic glass upon rapid liquid quenching have been identified. Binary glasses were obtained only over narrow composition ranges of 30–40 at.% Ni and ∼20 at.% Si; glass formation occurs over a much wider section of the ternary system, and selected ternary alloys, e.g. Ti 0.60Ni 0.30Si 0.10, form glasses more readily and were melt-spun to a glass. Related glasses, e.g. TiNiB and TiFeSi alloys, were also made. The glass forming ability of the alloys has been related to relatively low melting points, the size differences of the components and the presence of complex intermediate phases. The crystallization temperatures T c and Vickers diamond pyramid hardnesses H of selected alloys were determined; H ranged from 540 to 1070 kg/mm 2 and T c ranged from 700 to over 1000 K for a heating rate of 80 K/min. Values for both quantities increase when either Ti or Ni is replaced by Si or when Ti is replaced by Ni. While H changes linearly with T c for a section at 10 at.% Si, no universally valid relation between H and T c was observed. Specific strength values, UTS/ρ, have been estimated from hardness data and may range up to 59 × 10 5cm.