Annealing-induced devitrification behavior of a Ti_47.4Zr _5.3Ni_5.3Cu_42.0 glassy alloy

We have investigated devitrification behavior, accompanied by glass transition and precipitation of crystallites, as a function of annealing temperature and time for a Ti_47.4Zr_5.3Ni _5.3Cu_42.0 glassy alloy sheet, together with embrittlement behavior using bending fracture strain test. From kinetic analysis in one DSC profile under a constant heating rate, we can easily estimate the devitrification with temperature and time upon annealing. The glassy alloy became brittle during progressive devitrification in accordance with kinetic estimation. In sharp contrast with a Zr₅₅Al₁₀Ni ₅Cu₃₀ glassy alloy, all the precipitations of crystallites (Cu₄Ti₃, Ti and CuTi) occur above glass transition temperature (Tg). We found that the Ti-based glassy alloy has large structurally and thermally stable area, which does not brittle up to 1.10 × 10 ⁴ s at 650 K and 1.29 × 10¹⁰ s at 600 K, by experiment and kinetic estimation, respectively.