TB9钛合金棒线材制备过程中微观组织和力学性能演变

Evolution of Microstructure and Mechanical Properties of TB9 Alloy Bar and Wire during Production Process

  • 摘要: 通过光学显微镜、扫描电镜、电子背散射衍射技术等系统研究了TB9钛合金棒线材在制备过程中的微观组织及力学性能的演变过程。结果表明:通过真空自耗电弧熔炼、锻造、轧制及拉拔等工艺能够制备出表面质量良好、横截面组织性能一致的不同规格TB9钛合金棒线材产品。其中,开坯锻态组织由随机取向的粗大β相及极少量动态再结晶(DRX)晶粒构成,平均晶粒尺寸在1 000 μm以上。径锻态组织主要由约400 μm的β晶粒构成,累计应变的增加使得DRX晶粒百分数增加。多道次热变形获得的 ϕ10 mm棒材盘圆组织由尺寸为15 μm的细小晶粒组成,具有显著的热加工变形特征,固溶水冷处理能使组织均匀并获得无畸变β晶粒。热拉拔变形能够进一步细化晶粒,并提高TB9钛合金强度,强度最高可达1 100 MPa以上,但塑性有所下降。

     

    Abstract: The evolution of microstructures and mechanical properties of TB9 titanium alloy bar and wire during the production process is systematically studied by means of optical microscope, scanning electron microscope and electron backscattered diffraction. The results show that the TB9 titanium alloy bar and wire with good surface quality, consistent cross-section microstructures and properties can be prepared by vacuum consumable arc melting, forging, rolling and drawing. The as-forged microstructure is composed of randomly oriented coarse β grains and very few dynamic recrystallization(DRX) grains, with an average grain size of more than 1 000 μm. The radial forged microstructure is mainly composed of β grains with the size of about 400 μm, and the increase of cumulative deformation increases the DRX fraction. The microstructure of ϕ10 mm wire rod obtained by multi-pass hot deformation is composed of fine grains of 15 μm, which has obvious hot deformation characteristics. Compared with air cooling, the water cooling of solid solution treatment can obviously uniform the microstructure and obtain distortionless β grains. The hot drawing deformation can further refine the grains and improve the strength of TB9 titanium alloy up to more than 1 100 MPa, while reduces the plasticity.

     

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