首页> 外文学位 >An analysis of the grain refinement of magnesium by zirconium.
【24h】

An analysis of the grain refinement of magnesium by zirconium.

机译:锆对镁晶粒细化的分析。

获取原文
获取原文并翻译 | 示例

摘要

A Design of Experiments (DOE) approach was used to conduct a systematic study of the grain refinement of magnesium by zirconium; variables included the amount of zirconium, the pouring temperature, and the settling time prior to casting. Samples were poured into a special "hockey puck" mold designed to reproduce the conditions in permanent mold casting. Optical and scanning electron microscopy (SEM) was utilized to measure the grain size in the final microstructure. Sample dissolution followed by SEM was used to characterize zirconium particle size and morphology both in the master alloy and grain refined samples, while an AccuSizer 770 Photozone/Light Obscuration instrument was used to measure total particle size distributions in the master alloy and grain refined samples. Transmission Electron Microscopy (TEM) was used to identify particles that likely act as suitable heterogeneous nucleation sites for grain refinement. The TEM results show that a range of particle sizes are likely substrates and that only zirconium particles which are faceted are likely nucleation sites. It is apparent that only 1 to 3% of the total particles serve as nucleation sites, but a comparison of the grain density vs. faceted particle density shows close agreement. Equal Channel Angular Extrusion (ECAE) processing of the magnesium-15wt% zirconium master alloy to increase the number of faceted particles resulted in improved grain refinement efficacy. This work suggests that there is a tremendous potential to engineer a more efficient grain refiner.
机译:实验设计(DOE)方法用于对锆对镁的晶粒细化进行系统的研究。变量包括锆的量,浇注温度和铸造前的沉淀时间。将样品倒入专门的“曲棍球”模具中,该模具旨在复制永久铸模中的条件。利用光学和扫描电子显微镜(SEM)来测量最终微观结构中的晶粒尺寸。样品溶解后再用SEM表征母合金和晶粒细化样品中锆的粒径和形态,而AccuSizer 770光区/光遮蔽仪用于测量母合金和晶粒细化样品中的总粒径分布。使用透射电子显微镜(TEM)鉴定可能充当晶粒细化的合适异质成核位点的颗粒。 TEM结果表明,一定范围的粒径可能是基质,只有刻面的锆颗粒才可能是成核位点。显然,总颗粒中只有1%至3%用作成核点,但是晶粒密度与刻面颗粒密度的比较显示出紧密的一致性。镁含量为15wt%的锆母合金的等通道角挤压(ECAE)工艺可增加刻面颗粒的数量,从而提高了晶粒细化效果。这项工作表明,设计更高效的晶粒细化器具有巨大的潜力。

著录项

  • 作者

    Saha, Partha.;

  • 作者单位

    The University of Alabama.;

  • 授予单位 The University of Alabama.;
  • 学科 Engineering Metallurgy.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 98 p.
  • 总页数 98
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

  • 入库时间 2022-08-17 11:36:43

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号