Effects of friction stir processing and minor Sc addition on the microstructure, mechanical properties, and damping capacity of 7055 Al alloy

摘要

AbstractThis study investigated the effects of friction stir processing (FSP) and addition of 0.25% (mass ratio) Sc on the microstructure, mechanical properties, and damping capacity of AA 7055 alloy. Microstructure analyses revealed that a low tool rotation rate of 300rpm effectively inhibited the grain coarsening in the recrystallization of the alloy during FSP. Sc addition prevented the coarsening of grains and precipitated η phase and the annihilation of dislocations in the FSP AA 7055 alloy. After being subjected to FSP at 300rpm, the AA 7055 alloy containing Sc exhibited good mechanical and damping properties, which were mainly attributed to the fine recrystallized grain structure, fine precipitated η phase, and large number of nano-sized Al3(Sc, Zr) particles located at the grain boundaries and dislocations. This work provides an effective strategy for preparing commercial Al alloys with excellent damping capacity and mechanical properties.Highlights?Good mechanical and damping properties were obtained in the 7055 after FSP and Sc addition.?The strengthening and damping mechanisms of FSP 7055(-Sc) were analyzed.?FSP and Sc addition were found to be strategy of preparing 7xxx alloys with well damping and mechanical properties.]]>