Patel, SoorajSoorajPatelKumar, RahulRahulKumarMishra, SushilSushilMishraArora, AmitAmitArora2025-08-312025-08-312024-01-0110.1007/s11665-024-10597-12-s2.0-85212519665https://d8.irins.org/handle/IITG2025/29193This research investigates the impact of shoulder-workpiece separation on the friction stir channeling of copper, comparing two distinct tool designs. One design includes a clearance between the tool shoulder and workpiece; while, the other utilizes a grooved tool shoulder to eliminate this clearance. The findings reveal that direct contact between the tool shoulder and workpiece in the no-clearance design significantly affects the channel’s dimensions, microstructure, and mechanical properties. Notably, a distinct interface separating microstructural zones acts as a crack initiation site under tensile stress, leading to premature fractures of the channel roof. The results suggest that channels fabricated with shoulder-workpiece clearance improve tensile strength, offering a promising approach for manufacturing advanced heat sinks.falseFracture mechanism | Friction stir channeling | Heat sinks | Mechanical properties | MicrostructureArticle1544102420240121600arJournal0WOS:001380466300001