GALCIT Colloquium

Metal 3D printing has garnered a lot of attention over the last 5 years. The basic technology, however, is more than 30 years old [1]. Some argue that the expiration of original patents is the reason behind the current surge of attention and start-up companies [2]. So, more than 30 years later, is it possible to regularly print metal parts?

In the first part of this presentation I will discuss the answer to this question by highlighting some current engineering challenges and basic material behavior questions that arise in this context. I will then focus my attention on our efforts to address some of them, namely, understanding and controlling Selective Laser Melting (SLM). In this process, two-dimensional slices of a part are "built" by a laser over successively stacked layers of metal powder to form a three-dimensional object. In particular, I will describe: (a) our combined experimental and modeling approach towards  understanding the temperature history of metal particles (SS 17-4 PH) in the neighborhood of a region melted by the laser beam and its effect on the resulting microstructure, and (b) a recent study we performed to monitor the evolution of the melt pool induced by the laser beam with ultrasound in real time [3].

Parts of this talk are joint work with Wei Cai (Stanford), Yi Shu (Stanford), Daniel Galles (Army Research Laboratories), Brandon McWilliams (Army Research Laboratories), and Nancy Yang (Sandia National Laboratories).

[1] Flynt, Joseph. "A Detailed History of 3D Printing," https://3dinsider.com/3d-printing-history/

[2] Filemon, Joseph. "How expiring patents are ushering in the next generation of 3D printing," https://techcrunch.com/2016/05/15/how-expiring-patents-are-ushering-in-the-next-generation-of-3d-printing/

[3] Kube, C. M., Shu, Y., Lew, A. J., & Galles, D. (2018). Real-Time Characterization of Laser-Generated Melt Pools using Ultrasound. Materials Evaluation, 76(4), 525-534.