J. Mater. Sci. Technol. ›› 2009, Vol. 25 ›› Issue (02): 273-276.

• Articles • 上一篇    下一篇

Preparation of semi-solid A356 alloy feedstock cast via a pipe consisting of partial inclined and partial vertical sections

杨小容;毛卫民   

  1. 北京科技大学铸造研究所
  • 收稿日期:2007-10-29 修回日期:2008-01-30 出版日期:2009-03-28 发布日期:2009-10-10
  • 通讯作者: 杨小容
  • 基金资助:

    国家自然科学基金;国家高技术研究发展计划（863）;国家重点基础研究发展规划（973）;国家自然科学基金;国家高技术研究发展计划（863）;国家重点基础研究发展规划（973）

Preparation of Semisolid A356 Alloy Feedstock Cast via a Pipe Consisting of Partial Inclined and Partial Vertical Sections

Xiaorong Yang1,2) and Weimin Mao1)†   

  1. 1) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
    2) School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China
  • Received:2007-10-29 Revised:2008-01-30 Online:2009-03-28 Published:2009-10-10
  • Contact: Weimin Mao
  • Supported by:

    the National Key Basic Research Foundation of China under grant No. 2006CB605203
    the National Hi-Tech Research Foundation of China under grant No. 2006AA03Z115 
    the National Natural Science Foundation of China under grant No.50774007

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摘要：

本研究采用斜管加直管的浇注工艺，系统制备了半固态A356铝合金浆料。试验表明，采用斜管加直管的浇注工艺在645℃及其以上的较高浇注温度下能够制备出组织理想的半固态A356铝合金浆料，并且在最佳的浇注温度下可以解决合金熔体在管内残留结壳的问题，这对于该技术的工业应用具有重要意义；斜管段的倾角大小影响（斜管+直管）浇注工艺的最佳浇注温度，斜管段的倾角增大，最佳浇注温度也随之提高，但是管内结壳的可能性也会增大，因此在保证形核率的情况下应该尽量选用倾角小的斜管段。半固态浆料组织的形成归功于管壁形核和流动引起的搅拌的综合作用，斜管段对形核率有重要影响，直管段则在产生强烈搅拌和形核方面都起了重要作用。

关键词: 半固态;组织;斜管;直管;初生α相

Abstract:

In the present work, the microstructures of A356 feedstock cast via a pipe consisting of partial inclined and partial vertical sections were investigated. The experimental results indicate that semisolid feedstock with ideal microstructures can be obtained at higher temperatures 645°C and above by the proposed process, and the solid shell inside the pipe can be avoided at the optimum pouring temperature. Thus the process is attractive for industrial applications. The slanted angle of inclined section has an influence on the optimum pouring temperature. That is, the bigger the slanted angle, the higher the optimum pouring temperature, but accordingly, the greater the possibility of solid shell occurring inside the pipe. Therefore, small slanted angle should be considered first on the premise of ensuring a certain nucleation. The formation of semisolid feedstock is owed to the coactions of wall nucleation and stirring resulting from fluid flow. The inclined section greatly affects nucleation, and the vertical section has an important effect on both nucleation and generating stirring.

Key words: Semisolid, Microstructure, Inclined pipe, Vertical pipe, Primary α-Al