| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
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Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales IV
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| Presentation Title |
Designing Stable θ'/L12 Co-precipitates in Cast and Additively Manufactured Al-Cu-Mn-Zr Alloys |
| Author(s) |
Jonathan Poplawsky, Richard Michi, Lawrence Allard, Sumit Bahl, Dongwon Shin, Alex Plotkowski, Amit Shyam |
| On-Site Speaker (Planned) |
Jonathan Poplawsky |
| Abstract Scope |
𝜃´ precipitates (Al2Cu) strengthen Al-Cu alloys, but coarsen and transform after relatively short >250C exposures. Luckily, Mn and Zr microsolute additions stabilize 𝜃´ for lengthy 350C exposures. Advanced microscopy and computational techniques reveal that interfacial Mn segregation stabilizes 𝜃´ for a long enough time to allow slower diffusing Zr atoms to form an L12 structure at coherent-𝜃´ interfaces. Atom probe tomography reveals continuous interfacial Zr segregation for up to 350C, 5,000h exposures and a Zr matrix content dependent segregation rate. Zr segregates to 𝜃´ interfaces an order of magnitude faster within additively manufactured Al-Cu-Mn-Zr due to a supersaturated matrix forming L12/𝜃´ co-precipitates after short aging times. 𝜃´ serves as a perfect template for forming stable planar L12-Al3Zr precipitates that remain after Cu dissolves from 𝜃´ for >350C exposures. Microscopy was conducted at ORNL’s CNMS, which is a U.S. DOE Office of Science user facility. |