Continuous refinement of the microstructure during crystallization of supercooled Zr41Ti14Cu12Ni10Be23 melts

Isothermal crystallization studies are performed on Zr41Ti14Cu12Ni10Be23 me lts between the liquidus and the glass transition temperature. The resultin g time-temperature-transformation diagram is in good agreement with the dat a obtained from containerlessly processed samples. The various solidificati on products are examined by electron microprobe. The investigations reveal the morphology and typical length scale of the microstructure as well as th e primarily solidified phases after crystallizing at different degrees of u ndercooling. The typical length scale decreases continuously with increasin g supercooling over five orders of magnitude. The number density of nuclei during primary crystallization is estimated from the microstructure. The re sults are discussed within several models, such as steady-state nucleation, spinodal decomposition, and a nonpolymorphic nucleation model. (C) 1999 Am erican Institute of Physics. [S0003-6951(99)05118-9].