J. Mater. Sci. Technol. ›› 2011, Vol. 27 ›› Issue (2): 159-164.

• Research Articles • 上一篇    下一篇

Microstructural evolution of rapidly solidified ZK60 powders during extrusion

zhangzhenya1,于化顺2,闵光辉2,王少卿2,Hui Yu2   

  1. 1. 江苏大学
    2. 山东大学
  • 收稿日期:2009-12-14 修回日期:2010-04-27 出版日期:2011-02-28 发布日期:2011-02-28
  • 通讯作者: 于化顺

Microstructural Evolution of Rapidly Solidified ZK60 Powders during Extrusion

Zhenya Zhang1,2), Huashun Yu1), Shaoqing Wang1), Hui Yu1), Guanghui Min1)   

  1. 1) Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
    2)School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China  
  • Received:2009-12-14 Revised:2010-04-27 Online:2011-02-28 Published:2011-02-28
  • Contact: Huashun Yu

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Abstract: The microstructural evolution of rapidly solidified (RS) ZK60 powders extruded at 250°C was investigated. It was shown that formation of new ultrafine grains took place through continuous dynamic recrystallization (CDRX), accompanied by the perfect bonding of powders via severe plastic deformation. At a low strain level, a well-defined structure made up of equiaxed and elongated subgrains was developed. Simultaneously, the operation of basal and non-basal dislocation slip led to the formation of low-angle dislocation cells (LADC) within the elongated subgrains. With increasing strain, the number and average misorientation of LADC increased, resulting in fragmentation of original elongation subgrains into a finally homogeneous fine-grained structure. Almost full-recrystallized structure with an average grain size of 0.4 μm was finally evolved after large cumulative strain. The results suggested that structural change was connected with thermal strain, where dislocation activities dominated this process.