| Autor: |
Shao, Lixiong, Sun, Gaoqiu, Zhao, Guoping, Deng, Yaqi, Li, Xianfeng, Li, Xiaodong, Chen, Dong, Xia, Cunjuan, Wang, Haowei |
| Zdroj: |
Composites Communications; December 2024, Vol. 52 Issue: 1 |
| Abstrakt: |
This study systematically investigated the effects of in-situ TiB2particles and Ti solutes on the grain structure, nanosized precipitates, precipitate-free zone (PFZ) near the grain boundaries, and the overall performance of the Al-Li-Cu-Xalloy. The TiB2particles are predominantly hexagonal or equiaxed in shape, with sizes primarily ranging from 30 to 250 nm and an average size of 126 nm. The addition of TiB2particles and Ti solutes effectively refines the grain size of the alloy. Incorporating in-situ TiB2particles significantly improves the Young's modulus and hardness of the composites. Furthermore, the presence of TiB2particles and Ti solutes accelerates the aging process, thereby reducing the time required to reach peak aging. During aging, δ′ precipitates gradually grow while decreasing in number density. TiB2particles have little effect on the size and number density of δ′ precipitates; however, TiB2particles promote the nucleation of T1-Al2CuLi precipitates, leading to more uniform and finer T1precipitates in the composites compared to the alloy without TiB2reinforcement. The half-width of δ′-PFZ in the Al-Li-Cu alloy and its composites follows the order: Ti-free composite > 1TiB2composite > 5M2S alloy. This indicates that adding TiB2particles facilitates the growth of the δ′-PFZ, while Ti solutes significantly inhibit its broadening. Moreover, lower aging temperatures enhance the inhibitory effect on the broadening of the δ′-PFZ. The addition of Ti solutes and in-situ TiB2particles leads to a significant improvement in mechanical properties. Critically, the underlying mechanisms driving the microstructural evolution and the resulting mechanical performance were thoroughly analyzed. |
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