Abstract
Cu-Sn alloys produced via laser powder bed fusion (L-PBF) additive manufacturing (AM) have gained significant attention because they combine the advantages of AM relevant to intricate component design with outstanding combinations of strength, ductility, and resistance to wear and corrosion. However, a detailed understanding of the microstructure that contributes to the enhancement of the mechanical properties of L-PBF Cu-10Sn alloys remains unclear. In particular, there is a lack of understanding of the formation mechanisms of the Sn-rich δ phase commonly observed in Cu-10Sn. This study reveals two distinct variants of the δ phase possessing unique morphological characteristics. These characteristics are attributed to the local solidification conditions inherent to the melt pool boundaries versus those at the interiors of melt pools. A phase transformation pathway that elucidates the origin of the morphological variants of the δ phase from the Sn-rich metastable phases during the cyclic heating of the AM process is proposed. We report superior mechanical properties in L-PBF Cu-10Sn compared to those of conventionally manufactured counterparts due to the synergistic contributions from grain boundaries, dislocations, and the δ phase. Notably, the δ phase alone contributes approximately 22 % to the overall strength observed in the L-PBF Cu-10Sn alloy. The discovery of two types of distinct Sn-rich δ phase offers key insights into precise microstructural control in AM Cu-Sn alloys to enhance mechanical properties, providing practical strategies for improving material performance for diverse applications in automotive, aerospace, and machinery industries.
| Original language | English |
|---|---|
| Article number | 104723 |
| Journal | Additive Manufacturing |
| Volume | 102 |
| DOIs | |
| State | Published - Mar 25 2025 |
Funding
This research was funded by the Australian Government through the Australian Research Council Discovery Early Career Researcher Award (DE220100527). The authors acknowledge the facilities and the scientific and technical assistance of the teams at Sydney Microscopy & Microanalysis (SMM), Sydney Manufacturing Hub (SMH), and Sydney Analytical, which are Core Research Facilities at the University of Sydney. SMM is the University of Sydney’s node of Microscopy Australia. We particularly acknowledge the dedicated assistance and insightful discussions provided by Drs Mehdi Eizadjou and Wen Hao Kan (SMH), regarding the L-PBF sample preparation. The contributions of Dr Hongwei Liu (SMM) to the TEM data analyses in Figs. 6 and 8 are acknowledged. Helpful discussions with Dr Kevin Sisco (The University of Sydney) on the solidification process for Fig. 11 are acknowledged gratefully. The authors acknowledge Dr Hongjian Wang for his support in mechanical testing, and Dr Rachel Zhong for her assistance with powder characterisations at Engineering Analytical Facility, at the University of Sydney. The authors also thank Prof Sophie Primig and Mr Nana Kwabena Adomako at the University of New South Wales (UNSW) for their expertise and support in the use of Thermo-Calc simulation. The authors are grateful for the support of Dr Bosong Li (UNSW) in compression tests. This research was funded by the Australian Government through the Australian Research Council Discovery Early Career Researcher Award (DE220100527). The authors acknowledge the facilities and the scientific and technical assistance of the teams at Sydney Microscopy & Microanalysis (SMM), Sydney Manufacturing Hub (SMH), and Sydney Analytical, which are Core Research Facilities at the University of Sydney. SMM is the University of Sydney's node of Microscopy Australia. We particularly acknowledge the dedicated assistance and insightful discussions provided by Drs Mehdi Eizadjou and Wen Hao Kan (SMH), regarding the L-PBF sample preparation. The contributions of Dr Hongwei Liu (SMM) to the TEM data analyses in Figs. 6 and 8 are acknowledged. Helpful discussions with Dr Kevin Sisco (The University of Sydney) on the solidification process for Fig. 11 are acknowledged gratefully. The authors acknowledge Dr Hongjian Wang for his support in mechanical testing, and Dr Rachel Zhong for her assistance with powder characterisations at Engineering Analytical Facility, at the University of Sydney. The authors also thank Prof Sophie Primig and Dr Nana Kwabena Adomako at the University of New South Wales (UNSW) for their expertise and support in the use of Thermo-Calc simulation. The authors are grateful for the support of Dr Bosong Li (UNSW) in compression tests. This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The publisher acknowledges the US government license to provide public access under the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
Keywords
- Cu-10Sn alloy
- Laser powder bed fusion
- Microstructure
- Phase transformation
- Strengthening mechanisms