(4f) A Novel Means of Measuring Key Thermphyscal Properties Needed for Additive Manufacturing in Space

Additive manufacturing (AM) is very important for long-term habitation in space. Processes include directed energy deposition and 3-D printing of metals. Space is a harsh environment where energy use must be vitally minimized and it thus important to use sophisticated process algorithms to remove excess energy use in AM processes. These algorithms must rely on accurate values of thermophysical properties (i.e., surface tension and viscosity) to optimize process conditions for a wide array of liquid metals and alloys. NASA and the National Academies in recent reports have acknowledged knowledge of precise thermophysical properties as essential for materials processing. Measurement of properties at high temperatures is currently accomplished through a small set of methods. A current method employs drop levitation using an electrostatic field and correlating decay rates to properties. The drawbacks are that the drop must be small and levitated by a high DC voltage, inhibiting use in inert gases due to electric arcing. The method outlined in this talk seeks to eliminate drawbacks using a novel means called electrostatic resonance of layers. This will be accomplished using forcing with AC fields across a layer of fluids. Interfacial patterns will be generated as a signal of resonance-induced instability. The critical voltage and the associated patterns at the resonant state can be measured to high accuracy and correlated to surface tension and viscosity via theoretical models.

Support is acknowledged from NSF NNX17AL27G and NASA 80NSSC 21K0352 and NNX17AL27G