High-strength and ductile lightweight cast aluminium alloys with superlattice nano-layered fibres (SNL) and core-shell nano-particles
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866910178202353664 |
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| author | Kumar, Hemant Kumar, Praveen Raabe, Dierk Gault, Baptiste Makineni, Surendra Kumar |
| author_facet | Kumar, Hemant Kumar, Praveen Raabe, Dierk Gault, Baptiste Makineni, Surendra Kumar |
| contents | Lightweight, high-strength structural materials are component enablers in transportation and aerospace, reducing carbon footprints and enhancing fuel efficiency. Cast aluminium alloys, mainly based on eutectic compositions, make up 85% of these materials but often fail catastrophically due to inefficient load transfer across the interfaces between the brittle eutectic phase and the ductile matrix. Here, we discovered that promoting a superlattice nano-layer (SNL) around the eutectic fibres, achieved by adding Zr to an Al-Gd near-eutectic alloy, enables excellent load transfer capabilities, resulting in a 400% increase in tensile ductility. The primary Al matrix also contains a high number density of superlattice core-shell nano-particles. This exceptional increase in formability is attributed to the ability of the SNL to prevent dislocations from accumulating at the weak and brittle eutectic fibre/matrix interfaces, thereby avoiding stress concentrations that would otherwise initiate fibre breakage and debonding. The core-shell nano-particles in Al cause a large number of dislocation cross/multiple-slips on {111} planes, forming ultra-fine (12 nm) dislocation networks that leverage substantial plastic strain accumulation. This atomic interface design overcomes the ductility limitations of cast-eutectic alloys, enabling them for structural applications. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_08327 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | High-strength and ductile lightweight cast aluminium alloys with superlattice nano-layered fibres (SNL) and core-shell nano-particles Kumar, Hemant Kumar, Praveen Raabe, Dierk Gault, Baptiste Makineni, Surendra Kumar Materials Science Lightweight, high-strength structural materials are component enablers in transportation and aerospace, reducing carbon footprints and enhancing fuel efficiency. Cast aluminium alloys, mainly based on eutectic compositions, make up 85% of these materials but often fail catastrophically due to inefficient load transfer across the interfaces between the brittle eutectic phase and the ductile matrix. Here, we discovered that promoting a superlattice nano-layer (SNL) around the eutectic fibres, achieved by adding Zr to an Al-Gd near-eutectic alloy, enables excellent load transfer capabilities, resulting in a 400% increase in tensile ductility. The primary Al matrix also contains a high number density of superlattice core-shell nano-particles. This exceptional increase in formability is attributed to the ability of the SNL to prevent dislocations from accumulating at the weak and brittle eutectic fibre/matrix interfaces, thereby avoiding stress concentrations that would otherwise initiate fibre breakage and debonding. The core-shell nano-particles in Al cause a large number of dislocation cross/multiple-slips on {111} planes, forming ultra-fine (12 nm) dislocation networks that leverage substantial plastic strain accumulation. This atomic interface design overcomes the ductility limitations of cast-eutectic alloys, enabling them for structural applications. |
| title | High-strength and ductile lightweight cast aluminium alloys with superlattice nano-layered fibres (SNL) and core-shell nano-particles |
| topic | Materials Science |
| url | https://arxiv.org/abs/2507.08327 |