挤压态Mg–9Al–Zn–0.5RE–Ca–Si合金微观组织和力学性能  

Microstructure and Mechanical Properties of as-Extruded Mg-9Al-Zn-0.5RE-Ca-Si Alloy

作　　者：臧兰兰 郑嫄 阎帅 王天宇 李文斌 车朝杰 程丽任[2,6] ZANG Lan-an;ZHENG Yuan;YAN Shuai;WANG Tian-yu;LI Wen-bin;CHE Chao-jie;CHENG Li-ren(CRRC Dalian Rolling Stock Co.,Ltd.,Liaoning Dalian 116022,China;State Key Laboratory of Rare Earth ResourcesUtilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;Roll Forg-ing Technology Research Institute,Jilin University,Changchun 130022,China;Changchun Equipment Technology ResearchInstitute,Changchun 130012,China;Engineering Research Center of Ministry of Education for Heavy Machinery,TaiyuanUniversity of Science and Technology,Taiyuan 030024,China;Ganjiang Innovation Research Institute,Chinese Academy ofSciences,Jiangxi Ganzhou 341119,China)

机构地区：[1]中车大连机车车辆有限公司,辽宁大连116022 [2]中国科学院长春应用化学研究所稀土资源利用国家重点实验室,长春130022 [3]吉林大学辊锻工艺研究所,长春130022 [4]长春设备工艺研究所,长春130012 [5]太原科技大学重型机械教育部工程研究中心,太原030024 [6]中国科学院赣江创新研究院,江西赣州341119

出　　处：《精密成形工程》2023年第5期26-35,共10页Journal of Netshape Forming Engineering

基　　金：国家自然科学基金(51901149);国家重点研发计划(2020YFE0204500);中国科学院赣江创新研究院自主部署项目(E055B003);长春市科技发展计划(21GD03);中国科学院重点部署项目(ZDRW-CN-2021-3-4-15);山西省青年科技研究基金(201901D211307);山西省高等学校科技创新项目(019L0625)。

摘　　要：目的改善AZ91镁合金在温度超过120℃时的力学性能。方法在AZ91合金中添加Ca、Si和La/Ce混合稀土元素。在360℃下等温挤压,平均挤压速度为1.2 mm/s,挤压比为30︰1,以探究Ca、Si和La/Ce混合稀土元素对AZ91合金力学性能、物相组成和显微组织等的影响。结果在AZ91挤压态合金中,与添加Si元素相比,Ca元素对挤压态合金的力学性能影响更大。在室温时,Mg–9Al–Zn–0.5RE–Si挤压态合金的屈服强度、极限抗拉强度和伸长率分别是254 MPa、306 MPa、7.0%,而Mg–9Al–Zn–0.5RE–0.5Ca挤压态合金的屈服强度、极限抗拉强度和伸长率分别是308 MPa、330 Ma、7.1%。Mg–9Al–Zn–0.5RE–0.5Ca–0.5Si挤压态合金室温力学性能最佳,其屈服强度、极限抗拉强度和伸长率分别是351 MPa、383 MPa、7.4%,说明Ca、Si这2种元素的协同作用可同时提高室温下AZ91合金的强度和塑性。在150℃和200℃下,Mg–9Al–Zn–0.5RE–0.5Ca–0.5Si合金仍然具有最佳的力学性能。在150℃下,其屈服强度、极限抗拉强度和伸长率分别为174 MPa、225 MPa、31.8%。在200℃下,其屈服强度、极限抗拉强度和伸长率分别为136 MPa、153 MPa、49%。挤压后合金中形成[1010]、[1120]平行于挤压方向的织构。结论经过360℃的热挤压后,由于动态析出、动态再结晶和织构的作用,显著提高了合金的拉伸性能。在室温、150℃、200℃下,Mg–9Al–Zn–0.5RE–0.5Ca–0.5Si挤压态合金的力学性能最佳,说明同时添加Ca、Si和La/Ce混合稀土元素有利于提高AZ91合金的耐热性。The work aims to improve the mechanical properties of AZ91 magnesium alloy at more than 120℃.Ca,Si and La/Ce mixed rare earth elements were added to AZ91 alloy.Isothermal extrusion was carried out at 360℃with an average extrusion speed of 1.2 mm/s and an extrusion ratio of 30︰1 to explore the effects of Ca,Si and La/Ce mixed rare earth elements on the mechanical properties,phase composition and microstructure of AZ91 alloy.Ca had a greater effect on the mechanical properties of AZ91 extruded alloy than Si.At room temperature,the yield strength,tensile strength and elongation of Mg-9Al-Zn-0.5RE-Si extruded alloy were 254 MPa,306 MPa and 7.0%,respectively.However,the yield strength,tensile strength and elongation of Mg-9Al-Zn-0.5RE-0.5Ca extruded alloy were 308 MPa,330 MPa and 7.1%,respectively.The mechanical properties of Mg-9Al-Zn-0.5RE-0.5Ca-0.5Si extruded alloy at room temperature were the best,and its yield strength,tensile strength and elongation were 351 MPa,383 MPa and 7.4%,respectively.It indicated that the strength and plasticity of AZ91 extruded alloy could be improved simultaneously through the synergistic action of Ca and Si.At 150℃and 200℃,Mg-9Al-Zn-0.5RE-0.5Ca-0.5Si alloy still had the best mechanical properties.At 150℃,the yield strength,tensile strength and elongation were 174 MPa,225 MPa and 31.8%respectively.At 200℃,the yield strength,tensile strength and elongation were 136 MPa,153 MPa and 49%respectively.After extrusion,and textures parallel to the extrusion direction were formed in the alloy.After 360℃hot extrusion,the tensile properties of the alloy can be significantly improved due to dynamic precipitation,dynamic recrystallization and texture.At room temperature,150℃and 200℃,the mechanical properties of Mg-9Al-Zn-0.5RE-0.5Ca-0.5Si are the best,indicating that the addition of Ca,Si and La/Ce mixed rare earth elements at the same time is beneficial to improving the heat resistance of AZ91 alloy.

关 键 词：稀土镁合金 挤压 背散射电子衍射 沉淀强化 耐热性 

分 类 号：TG379[金属学及工艺—金属压力加工]