The Ag/WC electrical contacts were prepared via powder metallurgy using 60 wt% Ag, 40 wt% WC, and small amounts of Co3O4 with varying WC particle sizes. After the fabrication of the contact materials, microstructure observations confirmed that WC-1 had an average grain size (AGS) of 0.27 μm, and WC-2 had an AGS of 0.35 μm. The Ag matrix in WC-1 formed fine grains, whereas a significantly larger and continuous growth of the Ag matrix was observed in WC-2. This indicates the different flow behaviors of liquid Ag during the sintering process owing to the different WC sizes. The electrical conductivities of WC-1 and WC-2 were 47.8% and 60.4%, respectively, and had a significant influence on the Ag matrix. In particular, WC-2 exhibited extremely high electrical conductivity owing to its large and continuous Ag-grain matrix. The yield strengths of WC-1 and WC-2 after compression tests were 349.9 MPa and 280.7 MPa, respectively. The high yield strength of WC-1 can be attributed to the Hall–Petch effect, whereas the low yield strength of WC-2 can be explained by the high fraction of high-angle boundaries (HAB) between the WC grains. Furthermore, the relationships between the microstructure, electrical/mechanical properties, and deformation mechanisms were evaluated.

1. Introduction
2. Experimental
3. Results and Discussion
4. Conclusion
Acknowledgement

• 김수빈(인하대학교 신소재공학과) | Soobin Kim (Department of Materials Science and Engineering, Inha University, Incheon 22212, Republic of Korea)
• 박소연(인하대학교 신소재공학과) | So-Yeon Park (Department of Materials Science and Engineering, Inha University, Incheon 22212, Republic of Korea)
• 이기안(인하대학교 신소재공학과) | Kee-Ahn Lee (Department of Materials Science and Engineering, Inha University, Incheon 22212, Republic of Korea) Corresponding Author
• 임종빈(LT 메탈㈜) | Jong-Bin Lim (LT Metal LTD., Incheon 22828, Republic of Korea)
• 권순호(LT 메탈㈜) | Soon Ho Kwon (LT Metal LTD., Incheon 22828, Republic of Korea)