工业纯钛的低温拉伸行为研究

Tensile Behavior of Commercial Pure Titanium at Low Temperature

  • 摘要: 研究了工业纯钛TA2在-196℃到25℃时的拉伸性能及塑性变形机制。结果表明, 随着温度的降低, TA2屈服强度和抗拉强度逐渐升高, 断后伸长率先升高后降低, 在-140℃达到最大值, 断面收缩率逐渐升高, 在-80℃达到79%后保持稳定。25℃、-80℃、-120℃、-196℃拉伸试样中均观察到孪晶、高密度位错、变形组织。25℃时, 拉伸试样中孪晶极少。-80℃、-120℃、-196℃时孪晶数量大幅度增加, 且不同温度拉伸样品中孪晶形态差异很大。25℃时, TA2拉伸过程中塑形变形为滑移主导, 随着温度降低, 挛生在拉伸塑性变形过程中发挥的作用逐渐增大。

     

    Abstract: The tensile properties and the deformation mechanism of commercial pure titanium in the temperature range from -196 ℃ to 25 ℃ were investigated. The results show that with the decreasing of temperature, the yield strength and tensile strength increase gradually, the percentage elongation after fracture increases steadily to the highest at -140 ℃ and then decreases, and the percentage reduction of area increases gradually to 79% at-80 ℃ and then remains stable. Twins, high density dislocation and deformed structures are found in specimens stretched at 25 ℃, -80 ℃, -120 ℃ and -196 ℃. At 25 ℃, twins are seldom found, while at -80 ℃, -120 ℃ and -196 ℃, the densities of twins increase rapidly and the morphologies of twins are of great difference. Slipping is the dominant deformation mode in the course of tension at 25 ℃, while as the temperature decreases, twin plays an increasing role in the plastic deformation.

     

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