An investigation of the limits of grain refinement after processing by a combination of severe plastic deformation techniques: A comparison of Al and Mg alloys

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

卷:712

Article

Sabbaghianrad, Shima^1,2  Torbati-Sarraf, Seyed Alireza^1,2  Langdon, Terence G.^1,2,3 

[1] Univ Southern Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA

[2] Univ Southern Calif, Dept Mat Sci, Los Angeles, CA 90089 USA

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

关键词: Aluminum;    Equal-channel angular pressing;    Hardness;    High-pressure torsion;    Magnesium;    Microstructure;   

DOI  :  10.1016/j.msea.2017.11.090

来源: Elsevier

【 摘 要 】

An Al-7075 aluminum alloy and a ZK60 magnesium alloy were processed by a combination of equal-channel angular pressing (ECAP) for 4 passes and high-pressure torsion (HPT) through total numbers of up to 20 turns. Processing by ECAP and HPT were performed at 473 K and room temperature, respectively. Mechanical testing showed an increase in the hardness value of the Al-7075 alloy after a combination of ECAP and HPT whereas in the ZK60 alloy the hardness was reduced. Microstructural images of the Al-7075 alloy revealed very significant grain refinement after a combination of ECAP + HPT compared to the individual processing techniques. By contrast, and consistent with the hardness measurements, the average grain size of the ZK60 alloy was larger after processing by the two-step SPD technique. These results are examined and an explanation is presented based on the available microstructural evidence.

【 授权许可】

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