Microstructure evolution and formation mechanism of interfaces in parallel gap resistance welding of stranded Ag-plated Cu conductor to Ag interconnector

Nannan Chen; Zhichao Wang; Guanzhi Wu; Xuebin Zhuo; Yuhan Ding; Yi Wei; Jusha Ma; Min Wang; Chen Shen; Bin Qian; Xueming Hua

Materials & Design (Feb 2024)

Microstructure evolution and formation mechanism of interfaces in parallel gap resistance welding of stranded Ag-plated Cu conductor to Ag interconnector

Nannan Chen,
Zhichao Wang,
Guanzhi Wu,
Xuebin Zhuo,
Yuhan Ding,
Yi Wei,
Jusha Ma,
Min Wang,
Chen Shen,
Bin Qian,
Xueming Hua

Affiliations

Nannan Chen: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Corresponding authors.
Zhichao Wang: Shanghai Institute of Space Power Sources, Shanghai 200245, China
Guanzhi Wu: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Xuebin Zhuo: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Yuhan Ding: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Yi Wei: Shanghai Institute of Space Power Sources, Shanghai 200245, China
Jusha Ma: Shanghai Institute of Space Power Sources, Shanghai 200245, China
Min Wang: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Chen Shen: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Bin Qian: Shanghai Institute of Space Power Sources, Shanghai 200245, China
Xueming Hua: Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Corresponding authors.

Journal volume & issue: Vol. 238
p. 112697

Abstract

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In space flexible solar arrays, stranded Ag-plated Cu conductors and Ag interconnectors are preferred materials for energy transmission. Parallel gap resistance welding is a solderless micro-joining process that favors the reliability of joints between stranded Ag-plated Cu conductors and Ag interconnectors. It was found the interfacial microstructure presented diversity and complexity while mechanical and electrical properties showed unusual nonlinear variations with welding voltage. This study aims to clarify the interfacial microstructure evolution and its effects on the joint properties while elucidating the microstructure formation mechanisms. A shift in the bonding mechanism at interfaces from solid-state diffusion to brazing was found as welding voltage reached a critical value (1.5 V). It eliminated micro gaps and built nano-scale interlocking structures, resulting in substantial improvement in mechanical properties. Increasing the welding voltage from 1.2 V to 1.4 V improved electrical conductivity due to the enlarged bonding area at interfaces. However, high welding voltage (1.6 V) led to degradation in the electrical conductivity of joints due to excessive Ag-Cu solid solution formed at interfaces. The key to fabricating high-strength and high-conductivity joints lies in achieving appropriate interfacial melting while reducing alloying by controlling peak temperature and shortening the duration above the Ag-Cu eutectic point.

Published in Materials & Design

ISSN: 0264-1275 (Print); 1873-4197 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/materials-and-design

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