Surface Tension and Viscosity of the Ni-Based Superalloys LEK94 and CMSX-10 Measured by the Oscillating Drop Method on Board a Parabolic Flight

Abstract

The surface tension and viscosity of the Ni-based superalloys LEK94 and CMSX-10 were measured by the oscillating drop method in a containerless electromagnetic processing device on board a parabolic flight airplane. Surface oscillations were recorded by 150 and 200 Hz frame rate digital cameras positioned in two perpendicular directions and by the inductive coupling between the oscillating sample surface and the oscillating circuit of the radio frequency heating and positioning generator. The surface tension as a function of temperature of LEK94 and CMSX-10 was obtained as r(T) = 1.73 À 4.51 9 10 À4 [T-1656 K (1383°C)] Nm À1 and r(T) = 1.71 À 5.80 9 10, respectively. The viscosity at the liquidus temperatures as 9.8 and 7.8 mPa.s, respectively. In addition, some basic thermophysical properties such as solidus and liquidus temperatures, densities at room temperature, and thermal expansion in the solid phase are reported.

Thermophysical Properties of Advanced Ni‐Based Superalloys in the Liquid State Measured on Board the International Space Station

“…From the obtained surface tension data in this and other studies, such as in refs. [26,51] the compound formation model by Novakovic and co-workers [51,56] predicts the surface tension of Ni-based superalloys satisfyingly well. The viscosity predictions by the equation of Mills et al [53] only explain the viscosity of CMSX-10 (however, not precisely), but cannot predict the viscosity of LEK94 and MC2.…”

“…The surface tension of LEK94, MC2, and CMSX-10 measured in the EML on ISS is lower than the values obtained by earlier studies. [26,51] Furthermore, the temperature dependency of the surface tension dγ/dT of LEK94 and CMSX-10 is smaller than that from the measurements aboard the parabolic flight [26] and on ground. [51] The compared measurement methods have different possible systematic error sources.…”

“…Readjustment of heater and positioner power settings as well as recalibration of the pyrometer's emissivity setting at the solidus temperature could be performed per telecommanding during flight operation if needed. [26] 2.3. Experimental Methods…”

“…Containerless processing using electromagnetic levitation under microgravity can be performed on board of parabolic flights. [26][27][28] But the limited time of microgravity (typically 20 s) per parabola limits the measurement precision, as well as the type of measurements that can be performed. The International Space Station (ISS), in contrast, offers a long duration of microgravity which enables the measurement cycles to be as long as 20 min (limited only by the duration of the signal link to the ISS).…”

“…Containerless processing using electromagnetic levitation under microgravity can be performed on board of parabolic flights . But the limited time of microgravity (typically 20 s) per parabola limits the measurement precision, as well as the type of measurements that can be performed.…”