Influence of grain size on the flow properties of an Al-Mg-Sc alloy over seven orders of magnitude of strain rate

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

卷:685

Article

Pereira, Pedro Henrique R.^1,2  Wang, Ying Chun³  Huang, Yi¹  Langdon, Terence G.¹ 

[1] Univ Southampton, Fac Engn & Environm, Mat Res Grp, Southampton S017 1BJ, Hants, England

[2] Minist Educ Brazil, CAPES Fdn, BR-70040020 Brasilia, DF, Brazil

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

关键词: Aluminium alloys;    Dynamic testing;    Equal-channel angular pressing;    Hall-Petch relationship;    Superplasticity;   

DOI  :  10.1016/j.msea.2017.01.020

来源: Elsevier

【 摘 要 】

Experiments were conducted to evaluate the flow properties of an Al-3Mg-0.2Sc alloy both without and with processing using equal-channel angular pressing (ECAP). The initial grain size was similar to 300 mu m and this was reduced to similar to 250 mu m by ECAP and then increased to similar to 600 mu m by annealing at 673 K for 10 min. Tests were conducted to determine the mechanical properties over seven orders of magnitude of strain rate from similar to 10(-4) to similar to 10(3) s(-1). The results confirm the validity of the Hall-Petch relationship in the material processed by ECAP. Shear banding occurred in the coarse-grained material during dynamic testing but in the ECAP-processed alloy there was only minor grain coarsening. There was evidence for dynamic strain ageing in both the coarse and the ultrafine-grained (UFG) alloy with a transition in flow mechanism at high temperatures from dislocation climb in the coarse-grained material to superplasticity in the UFG alloy.

【 授权许可】

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