Hemispherical total emissivity and specific heat capacity of deeply undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 melts

Hemispherical total emissivity and specific heat capacity of deeply undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 melts

High-temperature high-vacuum electrostatic levitation ~HTHVESL! and differential scanning calorimetry ~DSC! were combined to determine the hemispherical total emissivity eT , and the specific heat capacity cp , of the undercooled liquid and throughout the glass transition of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glass forming alloy. The ratio of cp /eT as a function of undercooling w...

Measurements of Specific Heat Capacity and Hemispherical Total Emissivity at High Temperatures Using a Feedback- Controlled Pulse-heating Technique

The Origins of Spontaneous Grain Refinement in Deeply Undercooled Metallic Melts

Phase-field modeling of rapid alloy solidification, in which the rejection of latent heat from the growing solid cannot be ignored, has lagged significantly behind the modeling of conventional casting practices which can be approximated as isothermal. This is in large part due to the fact that if realistic materials properties are adopted, the ratio of the thermal to solute diffusivity (the Lew...

Non-Equilibrium Solidification of Undercooled Metallic Melts

If a liquid is undercooled below its equilibrium melting temperature an excess Gibbs free energy is created. This gives access to solidification of metastable solids under non-equilibrium conditions. In the present work, techniques of containerless processing are applied. Electromagnetic and electrostatic levitation enable to freely suspend a liquid drop of a few millimeters in diameter. Hetero...

Conditions for metastable crystallization from undercooled melts

The limits of validity of Ostwald’s rule of stages are investigated theoretically in the case of crystallization of undercooled melts. The treatment is within the limits of capillary theory. Two basic models are compared: (1) According to the first one (model A), the phase with lower energy of formation of critical nucleus is predominantly formed. In an enantiotropic-type phase diagram there is...