Growth of the nano-phase intermetallic compounds and its effect on mechanical behavior of Au80Sn20/CrMnFeCoNi solder joints during isothermal aging

High entropy alloy (HEA) like CrMnFeCoNi is deemed to be the next generation of novel structure materials because of its high strength and toughness. So it is really worth to probe the joining behavior of CrMnFeCoNi as a latent structure material. However, there are few studies on joining materials under actual service condition. In this paper, we investigated the microstructure and mechanical properties of Au80Sn20/CrMnFeCoNi solder joint after aging. The results indicate that there is no new phase in the time of aging based on XRD data. The thickness of intermetallic compound (IMC) layer aged for 360 h reaches 6.31 mu m, 2.1 times larger than that of IMC without aging. Moreover, nanoscale Co3Fe7 particles grow gradually with extended aging time, reaching 560 nm at 360 h and growing nearly 1.5 times. But the Vickers hardness and shear strength decrease continuously with the extension of aging time. The results manifest the deterioration point of mechanical properties of solder joints, providing guiding significance for industrial application. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the microstructure and mechanical properties of aged Au80Sn20/CrMnFeCoNi solder joints. Results showed an increase in intermetallic compound thickness and size of Co3Fe7 nanoparticles with extended aging time, while Vickers hardness and shear strength continuously decreased.