|
1
|
Choudhuri D, Srinivasan SG, Gibson MA, Zheng Y, Jaeger DL, Fraser HL, Banerjee R. Exceptional increase in the creep life of magnesium rare-earth alloys due to localized bond stiffening. Nat Commun 2017; 8:2000. [PMID: 29222427 PMCID: PMC5722870 DOI: 10.1038/s41467-017-02112-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 11/07/2017] [Indexed: 11/25/2022] Open
Abstract
Several recent papers report spectacular, and unexpected, order of magnitude improvement in creep life of alloys upon adding small amounts of elements like zinc. This microalloying effect raises fundamental questions regarding creep deformation mechanisms. Here, using atomic-scale characterization and first principles calculations, we attribute the 600% increase in creep life in a prototypical Mg-rare earth (RE)-Zn alloy to multiple mechanisms caused by RE-Zn bonding-stabilization of a large volume fraction of strengthening precipitates on slip planes, increase in vacancy diffusion barrier, reduction in activated cross-slip, and enhancement of covalent character and bond strength around Zn solutes along the c-axis of Mg. We report that increased vacancy diffusion barrier, which correlates with the observed 25% increase in interplanar bond stiffness, primarily enhances the high-temperature creep life. Thus, we demonstrate that an approach of local, randomized tailoring of bond stiffness via microalloying enhances creep performance of alloys.
Collapse
Affiliation(s)
- Deep Choudhuri
- Department of Materials Science and Engineering, University of North Texas, Denton, TX, 76201, USA.
- Advanced Materials and Manufacturing Processes Institute, University of North Texas, Denton, TX, 76207, USA.
| | | | - Mark A Gibson
- CSIRO Manufacturing, Private Bag 10, Clayton South, Clayton, VIC, 3169, Australia
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Carlton, VIC, 3053, Australia
- Department of Materials Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Yufeng Zheng
- Center for Accelerated Maturation of Materials, Department of Materials Science and Engineering, The Ohio State University, Columbus, 43210, OH, USA
| | - David L Jaeger
- Materials Research Facility, University of North Texas, Denton, TX, 76201, USA
| | - Hamish L Fraser
- Center for Accelerated Maturation of Materials, Department of Materials Science and Engineering, The Ohio State University, Columbus, 43210, OH, USA
| | - Rajarshi Banerjee
- Department of Materials Science and Engineering, University of North Texas, Denton, TX, 76201, USA.
- Advanced Materials and Manufacturing Processes Institute, University of North Texas, Denton, TX, 76207, USA.
- Materials Research Facility, University of North Texas, Denton, TX, 76201, USA.
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.
| |
Collapse
|