Additive manufacturing (AM) provides the potential avenue to fabricate complex metallic parts with reduced time to market and material waste. However, while most mechanical properties of AM parts meet or exceed those of conventionally processed materials, the inferior fatigue properties of as-built parts attributed to the large and variable presence of porosity and surface defects present a critical roadblock to the implementation of AM parts in the aerospace and biomedical industries. This presents a challenge for the qualification of any load-bearing part without extensive post-processing and inspection. Further understanding of the underlying mechanisms behind the formation of these defects will assist in process adjustments to minimize flaws without relying entirely on post-processing. This work highlights newly developed capabilities to observe porosity developing in a moving melt pool using high-speed X-ray radiography in a custom built laser powder bed fusion (LPBF) system at Argonne National Lab. Additionally, the application of high-resolution X-ray microtomography is discussed as a tool to observe the evolution of porosity through each stage of post-processing (as-built, HIP, post-HIP heat treatments), as well as surface/near surface flaws that can act as stress concentrators.
- Develop a thorough understanding of the potential sources of defects that can lead to premature failure across many alloys and machines.
- Become familiar with the most cutting-edge methods of defect detection, both for research purposes and quality control.