低氧高纯钛极薄带的制备及其组织性能
Preparation and Microstructure Properties of Low Oxygen High-purity Titanium Metal Foil
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摘要: 以电子束熔炼(EBM)获得的厚11 mm的低氧高纯钛为原料,采用组合成形轧制技术制备厚度30 μm的极薄带,采用原子力显微镜(AFM)、光学显微镜(OM)和透射电镜(TEM)等方法表征极薄带的表面形貌及微观组织,研究极薄带的屈服强度、抗拉强度和断后总延伸率等力学性能。结果表明:材料在冷轧过程中发生超延展现象,总延展率达36 667%;极薄带厚度波动小,波动比为1.43%;轧制态时微观组织形成超细晶,主要由等轴晶粒和拉长晶粒组成,等轴晶粒平均尺寸小于300 nm,拉长晶粒宽度50~250 nm;退火态时微观组织绝多数晶粒为等轴晶,尺寸15~20 µm;极薄带塑性成形性能良好,屈服强度120 MPa、抗拉强度250 MPa,断后总延伸率10.1%,是一种比较理想的微成形原料。Abstract: Low oxygen and high-purity titanium with thickness of 11 mm was used as raw material, which was obtained by electron beam melting (EBM). The metal foil with thickness of 30 μm was prepared by combined forming rolling technology. The surface morphology and microstructure of the metal foil were characterized by atomic force microscope (AFM), optical microscope (OM) and transmission electron microscope (TEM), and the mechanical properties such as yield strength, tensile strength and total elongation after fracture were studied. The results show that extreme extensibility phenomenon occurs in the cold rolling process, and the total elongation rate reaches 36 667%; the uniform thickness fluctuation of the metal foil is small, and the fluctuation ratio is 1.43%; the As-rolled microstructure forms ultrafine grains, which are mainly composed of equiaxed grains and elongated grains. The average grain size of equiaxed grains is less than 300 nm, and the width of elongated grains is about 50 nm to 250 nm. Most of the grains in the annealed microstructure become equiaxed grains with a size of about 15-20 µm. The metal foil has good plastic formability, with yield strength of 120 MPa, tensile strength of 250 MPa and total elongation after fracture of 10.1%. It is an ideal micro-forming raw material.