含I相Mg-Zn-Y合金的高温变形行为和加工图

来源期刊:中国有色金属学报(英文版)2018年第4期

论文作者:M. CHAMAN-ARA G. R. EBRAHIMI H. R. EZATPOUR

文章页码:629 - 641

关键词:Mg-Zn-Y合金;I 相;加工图;微观组织;力学性能

Key words:Mg-Zn-Y alloy; I phase; processing map; microstructure; mechanical properties

摘    要:通过热压缩试验(温度300~450 °C,应变速率0.001~1 s-1)研究挤压态含Y元素的Mg-Zn 合金的微观组织和力学性能。用热加工图反映合金热变形的最佳条件和非稳定区。Mg-Zn和Mg-Zn-Y 合金的峰值应力、温度和应变速率的关系符合双曲正弦函数,激活能分别为177 kJ/mol和236 kJ/mol。流变应力曲线表明,Y的添加会增加峰值应力并减小峰值应变,且Mg-Zn-Y合金发生动态再结晶所需的应变比Mg-Zn合金的小。Mg-Zn-Y 合金的稳定区发生在:1) 300 °C,0.001 s-1;350 °C,0.01-0.1 s-1 和 400 °C,0.01 s-1;2) 450 °C,0.01-0.1 s-1。显微组织的观察结果显示,合金中主要的恢复机制是动态再结晶,Mg-Zn-Y合金发生完全动态再结晶的温度为450 °C。在高应变速率下,Mg-Zn-Y合金明显形成非稳定区。另外,Mg-Zn和Mg-Zn-Y合金的非稳定区域宽度随应变的增加而增加,这些区域还发生了孪生和严重变形。

Abstract: The microstructure and mechanical properties of extruded Mg-Zn alloy containing Y element were investigated in temperature range of 300-450 °C and strain rate range of 0.001-1 s-1 through hot compression tests. Processing maps were used to indicate optimum conditions and instability zones for hot deformation of alloys. For Mg-Zn and Mg-Zn-Y alloys, peak stress, temperature and strain rate were related by hyperbolic sine function, and activation energies were obtained to be 177 and 236 kJ/mol, respectively. Flow curves showed that the addition of Y element led to increase in peak stress and decrease in peak strain, and indicated that DRX started at lower strains in Mg-Zn-Y alloy than in Mg-Zn alloy. The stability domains of Mg-Zn-Y alloy were indicated in two domains as 1) 300 °C, 0.001 s-1; 350 °C, 0.01-0.1 s-1 and 400 °C, 0.01 s-1 and 2) 450 °C, 0.01-0.1 s-1. Microstructural observations showed that DRX was the main restoration mechanism for alloys, and fully dynamic recrystallization of Mg-Zn-Y alloy was observed at 450 °C. The instability domain in Mg-Zn-Y alloy was located significantly at high strain rates. In addition, the instability zone width of Mg-Zn and Mg-Zn-Y alloys increased with increasing strain, and cracks, twins and severe deformation were considered in these regions.

相关论文

  • 暂无!

相关知识点

  • 暂无!

有色金属在线官网  |   会议  |   在线投稿  |   购买纸书  |   科技图书馆

中南大学出版社 技术支持 版权声明   电话:0731-88830515 88830516   传真:0731-88710482   Email:administrator@cnnmol.com

互联网出版许可证:(署)网出证(京)字第342号   京ICP备17050991号-6      京公网安备11010802042557号