|Study on precipitated phases, dislocations and hardness in the HAZ of friction stir welded joint of 2024 aluminum alloy|
PENG LIU, KEYUN FENG, SHUBO XU, GEMING ZHANG, MEIQING CAO, JIANING LI, CHUANWEI SHI
vol. 55 (2017), no. 5, pp. 357 - 361
The microhardness, precipitated phases and dislocations in the heat-affected zone of friction stir welded joints of 2024 aluminum alloys were observed and analyzed by transmission electron microscopy. The test result indicated that there were some block precipitation particles, Al7Cu3Mg6 phase, in the HAZ close to advancing side. The precipitated phases, AlCu3 phase, can be observed in the HAZ close to retreating side. Al7Cu3Mg6 phase could enhance the hardness in the advancing side of joint. After FSW, AlCu3 precipitated phase and high-density dislocations were divided into some fine particles and the lower dislocation density regions, respectively. As a result, the hardness in this region showed the lowest value.
aluminum alloys, friction stir welding, heat-affected zone, microstructure
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