您目前所在的位置:首页 - 期刊简介 - 详细页面

铁道科学与工程学报

JOURNAL OF RAILWAY SCIENCE AND ENGINEERING

Vol. 17    Special 1    November 2007

[PDF Download]    [Flash Online]

    

Effects of microalloying on grain refinement behaviors and   hardness properties of wedge-shaped Al-Mg-Mn castings
LIU En-ke(刘恩克), YANG Fu-bao(杨福宝), XU Jun(徐 骏), SHI Li-kai(石力开)

National Engineering and Technology Research Center for Nonferrous Metal Matrix Composites,
General Research Institute for Nonferrous Metals, Beijing 100088, China

Abstract:The effects of microalloying elements Ti, Sc, Zr and Er on grain refinement behaviors and hardness properties of wedge-shaped Al-Mg-Mn alloy castings were investigated. The results indicate that alloys containing Sc and Zr can remarkably reduce the grain sizes of Al-Mg-Mn castings. Combination of Sc, Zr and Er can completely eliminate the columnar dendritic grains and further obtain refined grains with nondendritic sub-structure; the whole wedge-shaped cross-section of the casting consequently exhibits more homogeneous cast structures instead of the typical tri-crystal region structures. Large amounts of Al3Sc-based intermetallic compound particles, such as Al3(Sc1−x, Zrx), Al3(Sc1−x, Tix), Al3(Sc1−x−y, Zrx, Tiy) and Al3(Sc1−x−y, Zrx, Ery) are present in the microalloyed alloys, resulting from their numerously forming in high-temperature melt before solidification. These phases have the same L12-type crystal structure to Al3Sc phase as well as smaller misfits with the primary α(Al) grains, which leads to more efficient epitaxial growth for α(Al) grains on all crystal planes of these composite phases. The experimental alloys have been hardened in different levels and, show the low susceptibilities of hardness change with varying cooling rate. The high hardness of the castings are caused by grain-refined strengthening and solid solution strengthening.

 

Key words: Al-Mg-Mn alloy; filler metal; wedge-shaped casting; grain-refined strengthening; solid solution strengthening

ISSN 1672-7029
CN 43-1423/U

主管:中华人民共和国教育部 主办:中南大学 中国铁道学会 承办:中南大学
湘ICP备09001153号 版权所有:《铁道科学与工程学报》编辑部
------------------------------------------------------------------------------------------
地 址:湖南省长沙市韶山南路22号 邮编:410075
电 话:0731-82655133,82656174   传真:0731-82655133   电子邮箱:jrse@mail.csu.edu.cn