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研究高氧含量(0.30%,质量分数,下同)、工业水平氧含量(0.16%)和极低氧含量(0.06%)3种Ti-2Al合金在低温(77K)、室温和高温(673K)下的拉伸力学行为。结果表明:低温和室温下,随着氧含量的升高,材料强度提高,塑性降低。然而,高温673K下,不同氧含量Ti-2Al合金强度和塑性基本相同,材料强度和塑性对氧含量的依赖性显著降低。氧含量较低时,温度对Ti-2Al合金塑性影响很小。微观组织观察表明,随着温度的升高,工业水平及高氧含量Ti-2Al合金拉伸断口由脆性解理转变为延性韧窝。高温环境下,固溶氧原子扩散速率提高使Cottrel气团对位错滑移的阻碍减弱,均匀变形的结果导致高氧含量Ti-2Al合金延性改善。
Ti-2Al alloys with high oxygen content (0.30%, mass fraction), industrial level oxygen content (0.16%) and extremely low oxygen content (0.06%) were studied at low temperature (77K), room temperature and high temperature Under tensile mechanical behavior. The results show that with the increase of oxygen content, the strength of the material increases and the plasticity decreases at low temperature and room temperature. However, the strength and ductility of Ti-2Al alloy with different oxygen contents are basically the same at 673K and the dependence of material strength and ductility on oxygen content is significantly reduced. When the oxygen content is low, the temperature has little effect on the plasticity of Ti-2Al alloy. Microstructure observation shows that with the increase of temperature, the tensile fracture of Ti-2Al alloy with industrial level and high oxygen content changes from brittle cleavage to ductile dimple. Under high temperature, the diffusion rate of solid-solution oxygen increased the retardation of dislocation slip of Cottrel air mass, and the uniform deformation resulted in the ductility improvement of high oxygen content Ti-2Al alloy.