Mechanisms of Stress Relaxation in C17200 for Rolling Contact Connector's Flexures Under Cyclic Compression

Abstract

Rolling contact connector (RCC) plays a pivotal and indispensable role in enabling dynamic current transmission efficiently within the realms of aerospace engineering, radar systems, and wind power generation applications.The C17200 flexures in RCCs exhibit stress relaxation during service, degrading electrical performance over time. This study validates the mechanical equivalence between rolling and cyclic compression, proposing an accelerated testing method to investigate stress relaxation mechanisms in C17200 flexures. A three-stage relaxation mechanism was revealed: initial hardening (0-0.2×107 cycles) from dislocation multiplication, rapid decay (0.3-2×107 cycles) via dislocation annihilation and γ′ precipitate coarsening, and slow decay (>2×107 cycles) dominated by grain boundary sliding. Dislocation density decreased by 38.85%, correlating with 18.09% stress reduction. This work provides critical insights for designing durable flexures in electrical connectors.

Keywords: Cu-Be alloy, Stress relaxation, rolling contact connector, Dislocation density