Effect of Ta on microstructure and corrosion resistance of TA23 alloy
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摘要: 利用金相显微镜、X射线衍射仪、显微硬度仪和电化学工作站研究了微量Ta元素对TA23合金显微组织、物相、维氏硬度及腐蚀性能的影响。结果表明,加入Ta元素之后,初生α相比例有不同程度的增大,且次生α相比例明显减少;对含Ta双态组织TA23合金进行X射线衍射谱分析发现没有出现新的衍射峰,即合金中无新相生成。当合金中Ta含量为0.5%时,(10-11)α的峰强度明显增高,织构更明显;通过显微硬度测试发现双态组织TA23合金的硬度出现下降,这主要是Ta元素加入后,合金中塑性较好的初生α相比例增大导致。对双态组织TA23合金进行动电位极化曲线测试,发现加入微量Ta元素之后合金的自腐蚀电位增高,自腐蚀电流密度下降,耐腐蚀性能提高,Ta元素的加入降低了钛合金的阳极活性。当Ta含量为0.5%时,初生α晶粒尺寸增大,减少了腐蚀原电池的形成,提高了钛合金在海水中的耐腐蚀性能。Abstract: The effect of Ta element on the microstructure, phase compositions, microhardness and corrosion resistance of TA23 alloy was investigated by means of optical microscopy, X-ray diffraction, Vickers hardness tester and electrochemical workstation. The results show that the proportion of primary α phase increases to some extent and the proportion of secondary α phase decreases obviously in the alloy with Ta added. The X-ray diffraction indicates that there is no new phase identified in the alloy after addition of Ta. At 0.5% of Ta in the alloy, the peak intensity of (10-11) α increases significantly. The microhardness of TA23 decreases slowly as the Ta content increases, which is attributed to the increase of soft α phase in the alloy with Ta added. The potentiodynamic polarization curves suggest that after addition of Ta element, the corrosion resistance of TA23 alloy is improved. When the Ta content is 0.5%, the size of primary α phase increases, which reduces the formation of corrosion battery and improves the corrosion resistance of titanium alloy in seawater.
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Key words:
- TA23 /
- microstructure /
- microhardness /
- potentiodynamic polarization curve /
- corrosion resistance
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表 1 合金化学成分
Table 1. Chemical compositions of different samples
% Al Zr Nb Mo Ta TA23 6.38 2.00 3.11 1.06 0 TA23-0.2%Ta 6.38 2.10 3.36 1.19 0.2 TA23-0.5%Ta 6.25 2.06 3.41 1.15 0.5 表 2 不同Ta含量双态TA23合金在人工模拟海水溶液中的电化学参数
Table 2. Electrochemical parameters of polarization curves of the TA23 alloys in simulated seawater
φcorr(vs SCE)/V Jcorr/(A·cm−2) TA23 −1.46 1.119×10−5 TA23-0.2%Ta −1.34 1.49×10−6 TA23-0.5%Ta −1.09 1.43×10−6 -
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