Invited as an alumni of the Worshipful Company of Armourers and Brasiers, I gave a talk about one of my favourite technology concepts below!
Title: Ask Me Anything on Additive Manufacturing Aerospace (AMA-AMA)
Abstract:
Zhen Rong Yap is a 3rd year undergraduate Jardine Scholar in Materials Science at the University of Oxford and was a research and technologist intern at the NASA Jet Propulsion Laboratory. He carried out computational and experimental research on materials thermodynamics simulation, spacecraft heat rejection systems, and magnetic shielding for radiation protection/ion engines. The talk is on integrated computational materials engineering (ICME) for additive manufacturing, encompassing modelling for functionally graded materials, new joining methods, and complex topologies. By combining computational, characterisation and physical testing methods, a model of the materials and components for flight project qualification can be constructed.
Time: 3 minutes
Talk transcript below:
Molecular fabricators, the dream, a machine that can make anything transition from one material to another with complex topologies all in one component. What is the solution? Lots of scary looking triangles.
Over the summer, I was an intern at the NASA Jet Propulsion Laboratory in computational materials and additive manufacturing. I worked on materials thermodynamics simulation, spacecraft heat rejection systems, and magnetic shielding for radiation protection/ion engines. One of the big projects my group was working on was functionally graded materials!
What is that?
It is a method of additively manufacturing materials with two different powders and varying the composition of the material. Which means you can go from Titanium to Steel or Tungsten to Aluminium. However, when you print just Titanium to Steel, you get lots of deleterious sigma phases. So you turn to computation. By putting multiple ternary phase diagrams next to each other, you can design a pathway to go through the phase diagrams and avoid the sigma phases. Like the captain of a ship through the materials space! By adding thermodynamic and kinetics modelling you can get better accuracy. This is important as additively manufactured materials are not at equilibrium. This means you use a thermodynamics library called PyCALPHAD. So to make sure your pathway works, use Kawin and PyCALPHAD along with thermocalc. Figure out the pathways and program it into your 3D printer.
For topology optimisation, the problem shifts. It becomes no longer just about which cells in a colouring book to colour in. You also need to choose the colour you want to colour it in. But if we can pull it off, we can build truly optimised structures. With spacecraft heat rejection systems, you can transition from aluminium to copper, with cutting tools, you can optimise the structure to be lightweight and tough but hard on the tips, materials that vary in magnetic shielding and conductive strips to conduct electrical signals and function as logic gates.
I imagine a world where you can specify the requirements of a device and algorithms can be run to converge on the materials thermodynamic and kinetic pathway required and topology. I believe the future of additive manufacturing and computational materials, even just individually are very capable and useful. But combined will be powerful tools in revolutionising technology.
