Intermediate temperature deformation behaviour of fine grained AZ61 alloy processed by hydrostatic extrusion

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

卷:530

Article

Victoria-Hernandez, J.¹  Hernandez-Silva, D.¹  Yi, S. B.²  Letzig, D.²  Bohlen, J.² 

[1] Inst Politecn Nacl ESIQIE, Dept Met Engn, Mexico City 07738, DF, Mexico

[2] Helmholtz Zentrum Geesthacht, Magnesium Innovat Ctr MagIC, D-21502 Geesthacht, Germany

关键词: Hydrostatic extrusion;    Superplasticity;    Texture;    Deformation mechanisms;   

DOI  :  10.1016/j.msea.2011.09.104

来源: Elsevier

【 摘 要 】

In this work, the intermediate temperature deformation behaviour of alloy AZ61 processed by hydrostatic extrusion has been examined. By means of this thermomechanical process it is possible to refine the microstructure to generate an average grain size of about 5 mu m directly from the as-cast microstructure in one single step when extruded at only 150 degrees C and an extrusion rate of 8 m/min. The evolution of microstructure and texture after tensile testing at 175, 200 and 225 degrees C in air at three different strain rates of 10(-2), 10(-3) and 10(-4) s(-1) were investigated. It was found that the alloy exhibited low temperature superplasticity at 175 degrees C (0.33T(m), where T-m is the melting point on the absolute scale). The maximum elongation recorded was 540% for AZ61 tested at 225 degrees C and 1.5 x 10(-3) s(-1). The intermediate temperature deformation behaviour and deformation mechanisms involved were discussed in terms of microstructure and texture development. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free