Grain Boundary Engineering in Additive Manufacturing (AM)

The Defense Logistics Agency (DLA) has a need to better understand grain boundaries (GB) to produce additively manufactured (AM) parts with more predictable mechanical behavior. Texas Research Institute Austin (TRI-Austin) proposes to develop an ultrasonic (UT) system capable of altering the microstructure of metallic systems during the AM process while being monitored in-situ using Laser Acoustic Emission (LAE). This unique approach will offer the capability of tailoring GBs of metallic systems for specific applications depending on processing parameters and UT frequency, while LAE provides a non-contact approach for flexible real time monitoring during manufacturing. Ultrasonic inspections on completed samples will demonstrate a reliable way to characterize microstructural features prior to mechanical testing. In Phase I, TRI will demonstrate the feasibility of using ultrasound with AM (UAM) and LAE to produce Ni 718 samples with improved mechanical properties while quantifying variability in manufacturing. In Phase II, TRI will look to manufacture more complex parts while adding a complimentary computational approach to provide more in-depth analysis of GB behavior to refine UAM capabilities or identify additional tools to design parts with more predictable failure modes at the microstructural scale while developing repeatable manufacturing procedures suitable for AM in a DLA environment.