东北大学学报（自然科学版）

东北大学学报:自然科学版 ›› 2015, Vol. 36 ›› Issue (8): 1102-1106.DOI: 10.12068/j.issn.1005-3026.2015.08.009

• 材料与冶金 • 上一篇    下一篇

挤压态Mg-1.2Zn-0.8Y合金组织及高应变速率下的力学行为

李洪晓， 李聪， 任玉平， 秦高梧   

  1. (东北大学 材料各向异性与织构教育部重点实验室， 辽宁 沈阳110819)
  • 收稿日期:2014-07-01 修回日期:2014-07-01 出版日期:2015-08-15 发布日期:2015-08-28
  • 通讯作者: 李洪晓
  • 作者简介:李洪晓(1968-)，女，山东荣成人，东北大学教授； 秦高梧(1970-)，男，江苏盐城人，东北大学教授，博士生导师.
  • 基金资助:
    国家自然科学基金资助项目(51271053)； 辽宁省自然科学基金资助项目(201202068).

Microstructure and Mechanical Behavior at High Strain Rates of As-extruded Mg-1.2Zn-0.8Y Alloy

LI Hong-xiao， LI Cong， REN Yu-ping， QIN Gao-wu   

  1. Key Laboratory for Anisotropy and Texture of Materials， Ministry of Education， Northeastern University， Shenyang 110819， China.
  • Received:2014-07-01 Revised:2014-07-01 Online:2015-08-15 Published:2015-08-28
  • Contact: LI Hong-xiao
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摘要： 通过显微组织观察、X射线及电子衍射结构分析对挤压态Mg98Zn1.2Y0.8合金的第二相结构及分布，以及Mg基固溶体组织形态进行了研究，并对其100/s ~667/s应变速率下的力学行为及断裂机制进行了分析.结果表明:Mg98Zn1.2Y0.8合金在300℃、挤压比为16的热挤压过程中发生了完全的动态再结晶；挤压态组织为晶粒细小的镁基固溶体、其上弥散分布的化合物H相，以及沿晶界分布的Z相.室温下随着应变速率从100/s提高到667/s，挤压态Mg98Zn1.2Y0.8合金的屈服强度及抗拉强度明显升高，延伸率也从9.2%提高到13%.室温下应变速率为100/s~667/s时挤压态Mg98Zn1.2Y0.8合金的拉伸断裂方式是以韧性断裂为主并伴有脆性断裂的混合断裂.

关键词: Mg-Zn-Y合金, 组织形态, 高应变速率, 力学行为, 断裂方式

Abstract: The structure of compounds and the microstructure of as-extruded Mg98Zn1.2Y0.8 alloy were investigated through OM， SEM， TEM and XRD. The dynamic behavior at high strain rate conditions of as-extruded Mg98Zn1.2Y0.8 alloy was also researched through the tensile test and fracture surface observation. The results show that the complete dynamic recrystallization occurs in the Mg98Zn1.2Y0.8 alloy during extruding process at a temperature of 300℃ and a reduction ratio of 16∶1. The fine particles of compound H-phase dispersively distribute in the Mg-based solid solution with fine grain size， and the particles of Z-phase mainly distribute along the grain boundaries. At room temperature， the yield strength and the tensile strength rise with the increase of strain rates from 100/s to 667/s， and the elongation also increases from 9.2% to 13%. Ductile fracture with some proportion of brittleness fracture occurs in the as-extruded Mg98Zn1.2Y0.8 alloy at room temperature and strain rate 100/s -667/s.

Key words: Mg-Zn-Y alloy, microstructure, high strain rate, mechanical behavior, fracture mode

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