Banded microstructure in 2024-T351 and 2524-T351 aluminum friction stir welds Part II. Mechanical characterization

ABSTRACT: A series of micro-mechanical experiments have been performed to quantify how the friction stir welding (FSW) process affects the material response within the periodic bands that have been shown to be a common feature of FSW joints. Micro-mechanical studies employed sectioning of small samples and micro-tensile testing using digital image correlation to quantify the local stress-strain variations in the banded region. Results indicate that the two types of bands in 2024-T351 and 2524-T351 aluminum FSW joints (a) have different hardening rates with the particle-rich bands having the higher strain hardening exponent, (b) exhibit a periodic variation in micro-hardness across the bands and (c) the individual bands in each material have the same initial yield stress.

Coordinates and geometry of specimen. Comparison of () curves between HSB and LSB, respectively, for fast, medium and slow FSW processing of AA2524-T351.
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