PDF《过热温度和时间对 Al-21%Si 合金凝固组织的影响》

第33 卷第4 期2012年4月材料热处理学报TRANSACTIONS OF MATERIALS AND HEAT TREATMENT Vol .

33 No .

4 April

2 0

1 2 过热温度和时间对 Al- 21%Si 合金凝固组织的影响 文滔1,

2 , 王建华 1, 2,

3 , 杨志增

2 , 郭启强

2 , 李雪梅

2 , 苏旭平 1,

3 ( 1. 常州大学材料科学与工程学院,江苏 常州 213164;

2. 湘潭大学机械工程学院,湖南 湘潭 411105;

3. 常州大学常州市先进金属材料重点实验室,江苏 常州 213164) 摘要: 将0.

5 g 初始铸态 Al- 21% Si 合金真空封装于

14 mm 的石英管中, 分别在

750、

800、

850 和900 ℃ 温度下重熔并保温不 同时间后水冷, 采用光学显微镜分析 Al- 21% Si 合金凝固组织.结果表明: Al- 21% Si 合金在

750 ~

850 ℃ 重熔保温

20 min 后初晶 硅比初始铸态合金中的更大, 但随着重熔温度的升高, 初晶硅的颗粒尺寸逐渐减小,

900 ℃ 温度下重熔时效果最好;

在750 ℃ 重熔 后初晶硅反而变粗, 保温时间对初晶硅颗粒的尺寸影响不明显;

在相对较慢的石英管水冷条件下, Al- 21% Si 合金中的共晶硅比 初始铸态组织中的共晶硅更加细小;

在750 ~

900 ℃ 温度范围内保温不同的时间后, 初晶硅的颗粒尺寸基本在

25 ~

43 μm 范围内 波动;

在

800、

850 和900 ℃ 保温时均出现了不同生长程度的五瓣星形初晶硅组织. 关键词: 过热温度;

保温时间;

Al- 21% Si 合金;

初晶硅;

凝固组织 中图分类号: TG166.

3 文献标志码: A 文章编号: 1009- 6264( 2012) 04- 0033-

05 Influence of overheating temperature and holding time on solidification microstructure of Al- 21%Si alloy WEN Tao1 , WANG Jian-hua1, 2,

3 , YANG Zhi-zeng1 , GUO Qi-qiang1 , LI Xue-mei1 , SU Xu-ping1,

2 ( 1. School of Materials Science and Engineering,Changzhou University,Changzhou 213164,China;

2. School of Mechanical Engineering,Xiangtan University,Xiangtan 411105,China;

3. Key Laboratory of Advanced Metal Materials of Changzhou City,Changzhou University,Changzhou 213164,China) Abstract: As-cast Al- 21% alloy with the weight of 0.

5 g was encapsulated into a

14 mm evacuated quartz tube,and then the quartz tubes were heated at 750,800,850 and

900 ℃ for different time. The solidification microstructure of the treated Al- 21% Si alloy was analyzed by optical microscopy. The results show that when overheated at

750 -

850 ℃ for

20 min,the primary Si is larger than that in the as received alloy. But the size of primary Si in the Al- 21% Si alloy gradually decreases with the increasing of temperature,and the solidified alloy with finest primary Si is achieved at

900 ℃ . While overheated at

750 ℃ ,the primary Si grows bigger than that in the as received alloy,and the effect of holding time on the size of primary Si is quite little. The eutectic Si in the alloy becomes smaller than that in the as received alloy because of lower cooling velocity. Most of the primary Si is with the size of

25 -

43 μm after overheating at

750 -

900 ℃ for different holding time. Five petal star-shaped primary Si with different growth level is observed for the alloy after overheating at 800,850 and

900 ℃ , respectively. Key words: overheating temperature;

holding time;

Al- 21% Si alloy;

primary Si;

solidification microstructure 收稿日期: 2011- 03- 26;

修订日期: 2011- 09-

14 基金项目: 国家自然科学基金( 51074030) ;

湖南省大学生创新基金, 青蓝工程资助 作者简介: 文滔(1985―) , 男, 主要从事铝合金熔体处理方面研究, E-mail: toweralvin@ 126. com. 通讯作者: 王建华( 1963―) , 男, 教授, 博士生导师, 从事铝合金组织 与性能研究, 发表论文50 余篇,