Simultaneous strength and ductility enhancements of high thermal conductive Ag7.5Cu alloy by selective laser melting

High electrical and thermal conductive metals (HETCM) play a key role in smart electronics, green energy, modern communications and healthcare, however, typical HETCM (e.g., Ag, Au, Cu) usually have relatively low mechanical strength, hindering further applications. Selective laser melting (SLM) is...

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Bibliographic Details
Published in:Scientific reports 2022-03, Vol.12 (1), p.4250-15, Article 4250
Main Authors: Xiong, Wei, Hao, Liang, Peijs, Ton, Yan, Chunze, Cheng, Kaka, Gong, Ping, Cui, Qian, Tang, Danna, Al Islam, Shamoon, Li, Yan
Format: Article
Language:English
Subjects:
639/166
639/301
Alloys
Copper
Ductility
Green energy
Heat conductivity
Humanities and Social Sciences
Lasers
Mechanical properties
Melting
Metals
Mimicry
multidisciplinary
Science
Science (multidisciplinary)
Thermal conductivity
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Summary:High electrical and thermal conductive metals (HETCM) play a key role in smart electronics, green energy, modern communications and healthcare, however, typical HETCM (e.g., Ag, Au, Cu) usually have relatively low mechanical strength, hindering further applications. Selective laser melting (SLM) is a potentially transformative manufacturing technology that is expected to address the issue. Ag is the metal with the highest thermal conductivity, which induces microscale grain refinement, but also leads to high internal stresses by SLM. Here, we select Ag7.5Cu alloy as an example to demonstrate that multi-scale (micro/meso/macro) synergies can take advantage of high thermal conductivity and internal stresses to effectively strengthen Ag alloy. The mimicry of metal-hardened structures (e.g., large-angle boundary) is extended to the mesoscale by controlling the laser energy density and laser scanning strategy to manipulate the macroscale internal stress intensity and mesoscale internal stress direction, respectively, to form mesoscale large-angle "grains", resulting in multiple mutual perpendicular shear bands during fracture. The presented approach achieved a significant enhancement of yield strength (+ 145%) and ductility (+ 28%) without post-treatment. The results not only break the strength-ductility trade-off of conventional SLM alloys, but also demonstrate a multi-scale synergistic enhancement strategy that exploits high thermal conductivity and internal stresses.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-022-08182-4