Containerless Measurements of Thermophysical Properties of Zr₅₄Ti₈Cu₂₀Al₁₀Ni₈

Abstract

High-temperature measurement and study of reactive materials can be difficult with conventional processing methods because contamination from the measuring apparatus and container walls can adversely affect measurements. Containerless processing techniques can be employed to isolate samples from their environment, reducing contamination. Benefits of containerless processing include reduction in heterogeneous nucleation sites, which in turn delays the onset of solidification and allows the study of meta-stable undercooled phases. However, property measurements must use noncontact methods as well. Fortunately, several optical-based methods have been developed and successfully employed to measure thermophysical properties, including surface tension, viscosity, density, and thermal expansion. Combining these techniques with the electrostatic levitator (ESL) located at the NASA Marshall Space Flight Center (MSFC) has resulted in an excellent facility to perform containerless material studies which support microgravity flight projects. Currently, studies of the thermophysical properties of liquid quasi-crystal forming and related alloys ranging from superheated to deeply undercooled states are being done with this facility in support of the NASA-funded flight project Quasi-crystalline Undercooled Alloys for Space Investigation (QUASI). While the primary purpose of these measurements is to support planned flight experiments, they are also a desirable resource for future manufacturing considerations and for fundamental insight in the physics of icosahedral ordering in liquids and solids. Presented here is an overview of the contactless measuring methods for surface tension, viscosity, density, and thermal expansion applied to Zr54Ti8Cu20Al10Ni8, for the superheated and meta-stable undercooled liquid phases, in support of QUASI.

Proposal for universality in the viscosity of metallic liquids

“…As shown in Fig. 4B , this same constrained expression also fits data obtained by other investigators 17 23 24 25 26 27 28 29 30 31 32 33 over a wide range of metallic glass families. Excluding a section for which measurements cannot be currently made, the universal curve fits well over 16 orders of magnitude in the viscosity.…”

MHD surrogate model for convection in electromagnetically levitated molten metal droplets processed using the ISS-EML facility

“…In this section we will demonstrate how this approach can be used even when the existing thermophysical property data is incomplete. The preceding TiZrNi results were generated using the best available data, as listed in Table 3 [18][19][20][21][22][23] . However, other datasets exist for Ti 39.5 Zr 39.5 Ni 21 for density, viscosity, and electrical conductivity.…”

Containerless Processing Studies in the MSFC Electrostatic Levitator

“…For example, density as a function of temperature is needed to model fluid flows. The measurement of density and thermal expansion can also be performed in the ESL 9 . The non-contact density measurement methods employed in ESL provide a resolution of approximately 300 parts per million, and are comparable to the best contact methods.…”