摘要
通过研究镁合金在高温时的氧化行为,旨在开发出高性能汽车用变形镁合金板材。制备了Mg-2Y-1.5Ce-0.6Zr合金,分别在450, 500, 600℃下进行轧制,通过使用扫描电子显微镜(SEM)、 X射线衍射仪(XRD)、电子万能试验机等仪器,对不同温度轧制后合金的组织变化、抗氧化性能、力学性能进行了系统分析。研究表明,合金在不同温度轧制后,表面形貌发生明显变化, 600℃轧制后合金表面氧化严重;合金微观组织沿晶界发生氧化,随着轧制温度升高,合金的氧化加剧;不同温度轧制后合金中并未产生新相,不同温度下的物相峰值有所变化;轧制过程中合金表面会形成一层致密且修复能力强的氧化膜,稀土元素在氧化膜中发生了扩散现象,氧化膜在600℃轧制后出现了显微裂缝;500℃轧制后合金的力学性能最好,其抗拉强度、屈服强度和延伸率分别为:340, 305 MPa和2.8%;3个温度轧制后合金的断裂方式相同,均为沿晶断裂。Mg-Y-Ce-Zr合金抗氧化性能好,不同温度轧制后合金的氧化膜未发生明显的增厚现象,轧制温度对合金的力学性能影响显著, 500℃轧制后合金的综合性能最好。
This paper aims to develop a high-performance wrought magnesium alloy for automotive applications by studying the oxidation behavior of magnesium alloys at high temperatures. The self-prepared Mg-2Y-1.5Ce-0.6Zr alloys were rolled at 450, 500, 600 ℃, respectively. After rolling at different temperatures, the microstructure, oxidation resistance and mechanical properties of the alloy were systematically analyzed by using scanning electron microscope(SEM), X-ray diffraction(XRD) and electronic universal testing machine. The results showed that the surface morphology of the alloy changed significantly after rolling at different temperatures, and the surface of the alloy was severely oxidized after rolling at 600 ℃. The microstructure of the alloy was oxidized along the grain boundary, and the oxidation of the alloy increased with the increase of rolling temperature. No new phase was formed in the alloy after rolling at different temperatures, and the peak value of phase changed at different temperatures. During the rolling process, a dense and strong repairing oxide film was formed on the surface of the alloy. The rare earth element diffused in the oxide film, and the oxide film appeared micro-crack after rolling at 600 ℃. After rolling at 500 ℃, the Mg-2Y-1.5Ce-0.6Zr alloy exhibited a superior combination of mechanical properties with tensile strength, yield strength and elongation of 340, 305 MPa and 2.8%, respectively. The fracture mode of the alloy after rolling was intergranular fracture. The Mg-Y-Ce-Zr alloy had good oxidation resistance, and the oxide film of Mg-Y-Ce-Zr alloy after rolling at different temperatures did not increase obviously. The rolling temperature had a significant effect on the mechanical properties of the alloy. After rolling at 500 ℃, the alloy had the best comprehensive performance.
作者
刘明华
王伟
徐瑞朝
王文礼
Liu Minghua;Wang Wei;Xu Ruizhao;Wang Wenli(School of Metallurgical Engineering, XV an University of Architecture and Technology, Xi'an 710055, China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2019年第8期800-807,共8页
Chinese Journal of Rare Metals
基金
陕西省科技新星项目(2012KJXX-33)
西安市科技计划项目(CXYJZKD003)
榆林市科技局项目资助
