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Creep mechanisms of an Al-Cu-Mg alloy at the macro- and micro-scale: Effect of the S'/S precipitate

Journal Article


Abstract


  • A novel methodology combining the macro- and micro-creep techniques was employed to study the effect of S0/S precipitate growth on the creep mechanism of an Al-Cu-Mg alloy. An AA2524 alloy was pre-aged at 180 ��C to obtain S0/S precipitates with various sizes. The results showed that the precipitate size increased approximately linearly to ���32 nm, ���60 nm, and ���105 nm after 3 h, 6 h, and 12 h of pre-aging, respectively. The growth of precipitate could significantly shorten the primary creep stage, despite the fact that the steady-state creep behavior was similar to that of the as-received alloy, as revealed by the macro tensile creep tests at 180 ��C and 180 MPa. This led to a stress exponent (2.4-2.5) of the Al alloy with various precipitate sizes that was quite close to that of the as-received Al alloy, implying a steady-state creep mechanism dominated by grain boundary sliding and dislocation interactions. Finally, the micro-creep tests showed a minor role of the precipitate size on the steady-state creep mechanism, as evidenced by the similar strain rate sensitivity (0.0169-0.0186), activation volume (���27 b3), and the results of a detailed transmission electron microscopy analysis of all tested alloys.

Publication Date


  • 2019

Citation


  • Xu, Y., Yang, L., Zhan, L., Yu, H., & Huang, M. (2019). Creep mechanisms of an Al-Cu-Mg alloy at the macro- and micro-scale: Effect of the S'/S precipitate. Materials, 12(18). doi:10.3390/ma12182907

Scopus Eid


  • 2-s2.0-85072562852

Volume


  • 12

Issue


  • 18

Place Of Publication


Abstract


  • A novel methodology combining the macro- and micro-creep techniques was employed to study the effect of S0/S precipitate growth on the creep mechanism of an Al-Cu-Mg alloy. An AA2524 alloy was pre-aged at 180 ��C to obtain S0/S precipitates with various sizes. The results showed that the precipitate size increased approximately linearly to ���32 nm, ���60 nm, and ���105 nm after 3 h, 6 h, and 12 h of pre-aging, respectively. The growth of precipitate could significantly shorten the primary creep stage, despite the fact that the steady-state creep behavior was similar to that of the as-received alloy, as revealed by the macro tensile creep tests at 180 ��C and 180 MPa. This led to a stress exponent (2.4-2.5) of the Al alloy with various precipitate sizes that was quite close to that of the as-received Al alloy, implying a steady-state creep mechanism dominated by grain boundary sliding and dislocation interactions. Finally, the micro-creep tests showed a minor role of the precipitate size on the steady-state creep mechanism, as evidenced by the similar strain rate sensitivity (0.0169-0.0186), activation volume (���27 b3), and the results of a detailed transmission electron microscopy analysis of all tested alloys.

Publication Date


  • 2019

Citation


  • Xu, Y., Yang, L., Zhan, L., Yu, H., & Huang, M. (2019). Creep mechanisms of an Al-Cu-Mg alloy at the macro- and micro-scale: Effect of the S'/S precipitate. Materials, 12(18). doi:10.3390/ma12182907

Scopus Eid


  • 2-s2.0-85072562852

Volume


  • 12

Issue


  • 18

Place Of Publication