We introduce a new method for overcoming the strength–ductility trade-off by using a non-metallic alloying method, whereby numerous oxygen atoms are introduced in a conventional A356 alloy (I-A356 alloy). Self-organized nanofibers containing oxygen atoms formed in the melt had a chemically coherent interface with the matrix after solidification. Furthermore, the nanofibers (~10 nm in width) developed small sub-grains (<1 μm in size) with wide low-angle boundaries within the grains. Pre-existing dislocations developed by the small lattice mismatch between the nanofibers and matrix promoted strong activities. The sub-grain boundaries do the role of dislocation cells during plastic deformation, imparting high elongation to the I-A356 alloy. In addition, finely dispersed Si-rich nanoprecipitates formed during the aging treatment. The oxygen-rich intermixed layer at the Al–Si interfaces with a small radius of curvature drove Al–Si interdiffusion owing to the high attractive binding energy with Al. Thus, in addition to Mg2Si precipitates, the Si-rich nanoprecipitates further enhanced the alloy strength. Therefore, both, the ultimate tensile strength and elongation to failure of the I-A356 alloy, significantly increased by approximately 69.6 MPa and 14.8%, respectively, in relation to those of the A356 alloy.
|Journal||Journal of Alloys and Compounds|
|Publication status||Published - 2022 Jul 5|
Bibliographical noteFunding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) ( 2017R1A2B2007062 ); and by the Technology Innovation Program ( 20012087 ) funded By the Ministry of Trade, Industry & Energy (MI, Korea).
© 2022 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry