Superior Strength and Ductility of In Situ Nano TiB2/Al-Cu-Mg Composites by Cold Rolling and Post-Aging Treatment

Junhui Tang; Jiwei Geng; Cunjuan Xia; Mingliang Wang; Dong Chen; Haowei Wang

doi:10.3390/ma12213626

Superior Strength and Ductility of In Situ Nano TiB₂/Al-Cu-Mg Composites by Cold Rolling and Post-Aging Treatment

Materials (Basel). 2019 Nov 4;12(21):3626. doi: 10.3390/ma12213626.

Authors

Junhui Tang^{1

2}, Jiwei Geng³, Cunjuan Xia⁴, Mingliang Wang⁵, Dong Chen^{6

7}, Haowei Wang⁸

Affiliations

¹ School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. junhuitang@sjtu.edu.cn.
² State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China. junhuitang@sjtu.edu.cn.
³ School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. gengjiwei163@sjtu.edu.cn.
⁴ School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. xiacunjuan@sjtu.edu.cn.
⁵ School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. mingliang_wang@sjtu.edu.cn.
⁶ School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. chend@sjtu.edu.cn.
⁷ State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China. chend@sjtu.edu.cn.
⁸ State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China. hwwang@sjtu.edu.cn.

Abstract

In this work, the combination of cold rolling with post-aging treatment is developed to achieve the optimal strength-ductility for the in situ nano TiB₂/Al-Cu-Mg composite. The microstructure and mechanical properties of the composite subjected to 20% thickness reduction of cold rolling at room temperature and their evolutions upon post-aging at different temperatures were investigated by means of a tensile test, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. It was found that the TiB₂ particles were effective in dislocation pinning and accumulation during the cold-rolling process. The tensile tests indicated that both the yield and ultimate tensile strengths of the cold-rolling sample increased a lot due to the dislocation strengthening and precipitation strengthening generated by dynamic precipitation during cold rolling in comparison with the conventional T6 sample. After aging at 100 °C/12 h, the elongation to failure reached ~8.4%, which was higher than the conventional T6 sample. Meanwhile, there was also a dramatic increase of strength. The yield and ultimate tensile strengths are ~644 MPa and ~726 MPa, respectively. This remarkable strength-ductility combination was due to the modified microstructure caused prior to artificial aging by the cold-rolling method and the formation of nanosized Guinier-Preston-Bagaryatsky (GPB) zones. The underlying mechanisms related to the superior strength-ductility combination were discussed regarding the microstructural characteristics in the composite.

Keywords: Al composite; GPB zones; aging behavior; in situ TiB2 particles; mechanical properties.

Abstract

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