轧制工艺对TC4ELI钛合金超宽幅厚板材组织与力学性能的影响

Effect of rolling process on microstructure and mechanical properties of TC4ELI titanium alloy with ultra-wide thickness plate

采用3种轧制工艺制备了δ42 mm×2100 mm×8000 mmTC4ELI钛合金板材,利用光学显微镜和万能拉伸试验机分析不同轧制工艺对TC4ELI宽幅厚板材的组织与性能的影响。结果表明:3种轧制工艺制备的板材组织分别为典型的变形魏氏、网篮和等轴组织,等轴组织具有较多的等轴初生α相,可产生均匀的应变,因此塑性良好;由于保留有原始β晶界的魏氏组织和网篮组织中的片状和短板条状的α束域取向不同使裂纹扩展路径变得曲折,故韧性较高,3种组织中网篮组织的强韧性匹配较好。根据海洋工程用钛合金材的工况条件,优选出合金强韧性匹配较好的轧制工艺。

δ42 mm×2100 mm×8000 mm TC4 ELI titanium alloy plates were prepared by three rolling processes. The effects of different rolling processes on microstructure and properties of the TC4 ELI wide and thick plates were analyzed by means of optical microscope and universal tensile tester. The results show that the microstructure of the TC4 ELI wide and thick plates prepared by three rolling processes is typical deformed widmanstatten, mesh basket and equiaxed microstructure, and the equiaxed microstructure has more equiaxial primary α phase, which can produce uniform strain, so the plasticity is good. Because of the different orientation of flake and short strip α beam domain, the crack propagation path becomes tortuous, so the toughness is higher, and the strength and toughness of the mesh basket microstructure match well. According to the working conditions of titanium alloy for marine engineering, the rolling process with good strength and toughness matching is optimized.