Effect of ECAP processing on microstructure evolution and dynamic compressive behavior at different temperatures in an Al-Zn-Mg alloy

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:684

Article

Afifi, Mohamed A.¹  Pereira, Pedro Henrique R.²  Wang, Ying Chun¹  Wang, Yangwei^1,3  Li, Shukui^1,3  Langdon, Terence G.² 

[1] Beijing Inst Technol, Sch Mat Sci & Engn, Beijing 100081, Peoples R China

[2] Univ Southampton, Fac Engn & Environm, Mat Res Grp, Southampton SO17 1BJ, Hants, England

[3] Natl Key Lab Sci & Technol Mat Shock & Impact, Beijing 100081, Peoples R China

关键词: Al-Zn-Mg alloy;    Dynamic mechanical properties;    Equal-channel angular pressing (ECAP);    Precipitation;    Ultrafine-grained materials (UFG);   

DOI  :  10.1016/j.msea.2016.12.099

来源: Elsevier

【 摘 要 】

An artificially aged Al-Zn-Mg alloy with a grain size of similar to 1.3 pm was processed by equal-channel angular pressing (ECAP) and then subjected to dynamic compression at a strain rate of 4000 s(-1) in the range from room temperature to 673 K. The results show the eta' phase is refined and a eta phase is formed during the first pass of ECAP and after further processing 8 passes the GP zones are removed. An ultrafine-grained (UFG) structure with an average grain size of similar to 200 nm was obtained after 4 passes. It is shown that dynamic compressive deformation assists the precipitation process through precipitate coalescence and by changing the precipitate orientations. The dynamic compressive yield strengths and flow stresses decrease gradually to different degrees with increasing temperature except after ECAP processing for 4 passes where there is thermal stability up to 473 K. The ECAP processing significantly improves the strength of the alloy at elevated temperatures by comparison with the as-received material.

【 授权许可】

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