摘要
采用光学显微镜、扫描电镜研究了铸态和均匀化态的Mg-9Gd-2Nd-0.8Al合金的显微组织,然后用Gleeble-1500D热模拟试验机对均匀化态合金在变形温度350~500℃,应变速率0.003~1 s^(-1)条件下进行了热压缩实验,计算了合金的变形激活能,构建并分析了合金的本构方程和热加工图。结果表明:铸态Mg-9Gd-2Nd-0.8Al合金主要由α-Mg基体和Mg_(5)Gd,Mg_(41)Nd_(5),Al_(2)RE相组成,经均匀化处理后(510℃×12 h),Mg_(5)Gd和Mg_(41)Nd_(5)相基本溶解,Al_(2)RE相保持稳定。均匀化态合金的流变应力曲线表现出动态再结晶的特征,其流变应力和峰值应力随温度的升高或应变速率的降低而显著降低,合金的变形激活能为185.836 kJ·mol^(-1)。合金在本实验的变形条件范围内存在两个失稳区:变形温度350~375℃,应变速率0.003~0.012 s^(-1)以及变形温度350~500℃,应变速率0.05~1 s^(-1),其最佳加工区域为变形温度445~500℃,应变速率0.003~0.01 s^(-1),合金在变形温度400℃,应变速率0.003 s^(-1)条件下的再结晶方式以非连续动态再结晶为主。
The microstructure of as-cast and homogenized Mg-9Gd-2Nd-0.8Al alloys was studied by an optical microscope and a scanning electron microscope.Then the hot compression experiment of homogenized alloy was carried out with Gleeble-1500D thermal simulation under the conditions of deformation temperature of 350-500℃and strain rate of 0.003-1 s^(-1).The deformation activation energy of the alloy was calculated,and the constitutive equation and hot processing map of the alloy were constructed and analyzed.The results show that as-cast Mg-9Gd-2Nd-0.8Al alloy is mainly composed of α-Mg matrix and Mg_5Gd,Mg_(41)Nd_5,Al_(2RE) phases.After homogenization treatment (510℃×12 h),Mg_(5Gd) and Mg_(41)Nd_(5) phases basically dissolve and Al_(2RE) phase remains stable.The flow stress curve of homogenized alloy shows the characteristics of dynamic recrystallization.The flow stress and peak stress decrease significantly with the increase of temperature or the decrease of strain rate.The deformation activation energy of the alloy is 185.836 kJ·mol^(-1).There are two instability zones within the deformation conditions of this test:deformation temperature of 350-375℃,strain rate of 0.003-0.012 s^(-1) and deformation temperature of 350-500℃,strain rate of 0.05-1 s^(-1).The best processing zone is deformation temperature of445-500℃,strain rate of 0.003-0.01 s^(-1).The recrystallization mode of the alloy under the deformation temperature of 400℃and strain rate of 0.003 s^(-1) is mainly discontinuous dynamic recrystallization.
作者
张子延
陈君
陈晓亚
李全安
刘建鑫
Zhang Ziyan;Chen Jun;Chen Xiaoya;Li Quan’an;Liu Jianxin(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023,China;Provincial and Ministerial Co-Construction of Collaborative Innovation Center for Nonferrous Metal New Materials and Advanced Processing Technology,Luoyang 471023,China)
出处
《中国稀土学报》
EI
CAS
CSCD
北大核心
2024年第1期128-137,I0004,共11页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金项目(51571084)
中原英才计划一中原青年拔尖人才项目(豫组通[2021]44号)
河南省自然科学基金项目(222300420435)资助。
作者简介
张子延(1997-),男,硕士研究生;通讯联系人:陈君,男,正高级实验师,硕士生导师,研究方向:稀土镁合金。E-mail:chenjun318822200@163.com。
