About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
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Additive Manufacturing, Directed Energy Deposition of Metals: Processing – Microstructure – Mechanical Property Relationships
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| Presentation Title |
Alloy Design of printable precipitation strengthened Al-Zn alloys using grain refinement and crack mitigation alloying strategies |
| Author(s) |
Anne Dunn, John Mackenzie O`Connell, Bhaskar Majumdar |
| On-Site Speaker (Planned) |
Anne Dunn |
| Abstract Scope |
Aluminum alloys manufactured using laser powder bed fusion undergo very rapid solidification that deviates from equilibrium conditions. In particular, elemental segregation leads to brittle intermetallic phases at dendrite and cell boundaries, which along with shrinkage stresses often lead to cracking along high angle grain boundaries. Precipitation strengthened Al-Zn alloys exhibit one of the highest strengths among Al-alloys and attractive for additive applications. However, their large solidification range makes them prone to cracking. This work proposes to show that modification of a base Al-Zn-Mg-Cu alloy with grain refiners scandium and zirconium, along with eutectic former silicon improves printability and prevents solidification cracking. CALPHAD non equilibrium solidification diagrams and the Kou Crack Susceptibility model are utilized to explain the mechanism of crack mitigation. Mechanical property data of samples subjected to different heat treatments will be presented and discussed. We gratefully acknowledge support under Army cooperative agreement W911NF2020190. |