|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Microstructural Templates Consisting of Isostructural Ordered Precipitate / Disordered Matrix Combinations: Microstructural Evolution and Properties
||Precipitate Strengthening and Stabilization Mechanisms in Cast and Additively Manufactured Al-Cu-Mn-Zr Alloys
||Jonathan Poplawsky, Richard A. Michi, Sumit Bahl, Brian Milligan, Patrick Shower, Lawrence Allard, Matthew F. Chisholm, Dongwon Shin, Kevin D. Sisco, Alex J. Plotkowski, Ryan R. Dehoff, Allen Haynes, Amit Shyam
|On-Site Speaker (Planned)
A microstructure rich in θ’ precipitates (Al2Cu) is critical for AlCu alloys’ strength, but these alloys soften after exposures to temperatures >250oC. Mn and Zr microsolute additions stabilize the θ’ microstructure after 350oC, >200 hrs exposures. Advanced microscopy and computational techniques revealed that interfacial Mn segregation creates solute drag and decreases the interfacial energy, which allows for the slower diffusing Zr/Ti to form an L12 structure at the θ’ interfaces, further stabilizing the microstructure. Recently, an additively manufactured (AM) Al-Cu-Mn-Zr (ACMZ) alloy was developed that is stronger than the cast-ACMZ counterpart after 200 hr exposures to 300, 350, and 400 °C, which is partly due to the unique microstructure and solute supersaturation achieved by rapid solidification. The differences in the microstructure and mechanical properties of the cast and AM-ACMZ alloys will be discussed. The microscopy was conducted at ORNL’s CNMS, which is a U.S. DOE Office of Science user facility.