热处理及热挤压对Mg-10Gd-4.8Y-0.6Zr组织及常温力学性能的影响  

Effects of heating treatment and hot extrusion on microstructures and room temperature mechanical properties of Mg-10Gd-4.8Y-0.6Zr alloy

作　　者：李慧中[1,2] 郭菲菲[1] 刘楚明[1] 刘洪挺[1] 王海军[1] 梁霄鹏[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2010年第4期338-343,共6页Materials Science and Engineering of Powder Metallurgy

基　　金：国防重大基础研究项目(2005年);中南大学博士后基金资助项目(2008-08);中国博士后基金资助项目(20070420828)

摘　　要：通过力学和显微硬度测试、能谱和X射线衍射分析以及光学显微镜、扫描电镜和透射电镜观察,对Mg-10Gd-4.8Y-0.6Zr合金经均匀化、挤压变形及时效处理后的显微组织和常温力学性能进行研究。结果表明,铸态合金经520℃/16 h均匀化处理后网状共晶消除,并有黑色方块相生成,强度和塑性显著提高;挤压变形后的合金,抗拉强度σb达304.5 MPa,比挤压前提高25%,屈服强度σ0.2成倍增加,达268.7 MPa;在200℃时效20 h后峰值硬度达到137 HV;再经挤压和峰值时效后最终σb为370 MPa,比挤压态合金试样提高22%,屈服强度σ0.2为295.6 MPa,提高10%,但伸长率δ略有下降;该合金在室温下的断裂方式是脆性和韧性断裂兼有的混合断裂。Microstructures and room temperature mechanical properties of Mg-10Gd-4.8Y-0.6Zr alloy in different treatment conditions were investigated by tensile test,energy dispersive spectrometer（EDS）,X-ray diffraction（XRD）,optical microscopy（OM）,scanning electron microcopy（SEM）,and transmission electron microscopy（TEM）.The results show that the network-like eutectic compounds in cast alloy dissolve,and black cuboid-shaped phases form after homogenized at 520 ℃ for 16 h.Both strength and plasticity of homogenized alloy increase obviously.The extrusion improves tensile strength by 25%,reaching 304.5 MPa,and yield strength increases in times,reaching 268.7 MPa.The peak hardness 137 HV can be obtained when aged at 200 ℃ for 20 h.After extrusion and ageing,tensile strength reaches 370 MPa increasing by 22%,and yield strength reaches 295.6 MPa increasing by 10%.The fracture mode of Mg-10Gd-4.8Y-0.6Zr alloy at room temperature is a mixed fracture with both brittle fracture and ductile fracture.

关 键 词：Mg-10Gd-4.8Y-0.6Zr合金 热处理 热挤压 组织 力学性能 

分 类 号：TG146[一般工业技术—材料科学与工程]