摘要
采用光学显微镜（OM）、扫描电镜（SEM）、X射线衍射（XRD）及室温拉伸等手段,研究元素Si对铸造Mg-Gd-Y-Zr合金组织与力学性能的影响。结果表明：Mg-10Gd-1Y-xSi-0.5Zr（x=0,0.5,1,1.5,2）合金的铸态和固溶时效态显微组织均由α-Mg、Mg5Gd和Mg24Y5相组成,Si的加入产生新相Mg2Si。随着Si含量的增加,铸态合金中枝晶状组织明显减少并逐渐消失,晶粒细化,合金的析出相增多。时效态合金中当Si含量增加至1 mass%时,合金组织化学成分最均匀,析出相呈颗粒状和棒条状分布于基体中。在室温下,铸态和时效态合金的抗拉强度,均随着Si含量的增加先升后降,Mg-10Gd-1Y-1Si-0.5Zr合金的抗拉强度最高,时效态合金强度达到最高为256.2 MPa,比Mg-10Gd-1Y-0.5Zr合金高出将近40 MPa。合金的伸长率随Si含量的增加而减小,其断裂方式都属脆性断裂。
Effects of Si content on microstructure and mechanical properties of Mg-Gd-Y-Zr casting alloy were investigated by means of optical microscope（ OM）,scanning electron microscopy（ SEM）,X-ray diffraction（ XRD） and tensile test. The results show that the microstructure of the as-cast and solution-aged Mg-10 Gd-1 Y-xSi-0. 5 Zr（ x = 0,0. 5,1,1. 5,2） alloy consists of α-Mg matrix,Mg5Gd and Mg24Y5 phases,and the addition of Si leads to the formation of new phase Mg2 Si. With the increasing of Si content,the dendrites in the as-cast alloy decreases obviously and disappears gradually,the grains are refined and the content of precipitate phase increases. After solid solution and aging treatment,when the content of Si is 1 mass%,the chemical composition of the alloy is the most uniform,and the precipitate phases distribute in the matrix as granular and rod-like shape. At room temperature,with the increasing of Si content,the tensile strength of the as-cast and solution-aged alloys increases first then decreases,and the mechanical properties of the Mg-10 Gd-1 Y-1 Si-0. 5 Zr alloy are the best. The tensile strength of the aged Mg-10 Gd-1 Y-1 Si-0. 5 Zr reaches 256. 2 MPa at room temperature,which is nearly 40 MPa higher than that of the Mg-10 Gd-1 Y-0. 5 Zr alloy. The elongation of the alloys decreases with the increasing of Si content,and the fracture modes are brittle fracture.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2018年第2期54-60,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51571084,51171059)
河南省重点科技攻关项目(152102210072)
