内含片状α相TA2纯钛组织的再结晶行为

    Recrystallization Behavior of TA2 Pure Titanium Containing Lamellar α Phase in Microstructure

    • 摘要: 室温强度低是限制TA2纯钛工程应用的重要因素,而细晶强化是提高TA2强度的关键机制。旨在通过单相区热处理在TA2组织中引入片状α相,随后通过冷轧及退火使其再结晶,进而分析其再结晶行为及对抗拉强度的影响。结果表明:TA2经910℃保温1 h冷却、80%冷轧及600℃退火后,其再结晶晶粒尺寸可控制在10μm以内。组织对比显示冷轧前组织形态对TA2再结晶行为有重要影响。组织中的片状α相在冷轧过程中发生弯折破碎,在后续退火时可形成更多的再结晶形核位点,导致晶粒细化效果较好。与不含片状α相的原始组织相比,单相区保温炉冷后形成的魏氏组织试样经冷轧+600℃退火后可将屈服强度提升约40 MPa,而塑性则基本保持不变。

       

      Abstract: Low room temperature strength is an important factor limiting the engineering application of TA2 pure titanium, and fine grain strengthening is a key mechanism to improve the strength of TA2. The purpose of the research is to introduce the lamellar α-phase into the TA2 microstructure by single-phase zone heat treatment, followed by its recrystallization by cold rolling and annealing, and then analyze its recrystallization behavior and its effect on tensile strength.The results show that the recrystallized grain size of TA2 can be controlled within 10 μm after cooling at 910 ℃ for 1 h, 80% cold rolling and 600 ℃ annealing. The microstructure comparison shows that the microstructure morphology before cold rolling has an important influence on the recrystallization behavior of TA2. The lamellar α phase in the microstructure bends and fractures during the cold rolling process, and more recrystallization nucleation sites can be formed during the subsequent annealing, leading to better grain refinement. Compared with the original microstructure without lamellar α-phase, the Weiss microstructure specimens forming after holding furnace cooling in the single-phase zone can increase the yield strength by about 40 MPa after cold rolling +600 ℃ annealing, while the plasticity remains largely unchanged.

       

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