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针对Ti6Al4V合金低温渗氮的问题,设计了一种渗氮工艺,研究了该工艺对Ti6Al4V合金组织和力学性能的影响。通过变形增强渗氮动力,使渗氮可以在较低温度(500°C)下实现,氮化与Ti6Al4V合金基体的弥散强化同时进行。实验过程为固溶强化→室温下冷轧变形→500°C低温渗氮。结果表明,在渗氮一段时间后,试样表面形成了白亮的氮化层并且趋于稳定,变形量和变形时间对氮化层的影响不明显。试样基体组织时效效果明显,表面硬度与基体组织硬度随变形量增加而增加。经XRD物相分析,试样表面生成的氮化物为Ti N、Ti_2N、Ti_4N_(3-X)和Ti_3N_(1.29),横截面氮化物为Ti_3N_(1.29)和Ti N_(0.3)。对经过变形、渗氮和时效等工艺的试样进行摩擦磨损实验,渗氮试样的耐磨性最好。
Aiming at the problem of low temperature nitriding of Ti6Al4V alloy, a nitriding process was designed and the effect of the process on microstructure and mechanical properties of Ti6Al4V alloy was studied. Nitriding can be achieved at lower temperature (500 ° C) by means of deformation to enhance nitriding power. Nitriding is carried out simultaneously with dispersion strengthening of Ti6Al4V alloy matrix. The experimental process is solid solution strengthening → cold rolling deformation at room temperature → low temperature nitriding at 500 ° C. The results show that after nitriding for a period of time, a bright white nitride layer is formed on the sample surface and tends to be stable. The effect of deformation amount and deformation time on the nitride layer is insignificant. The effect of microstructure and aging of the sample matrix is obvious. The surface hardness and matrix hardness increase with the increase of deformation. The XRD analysis shows that the nitrides are TiN, Ti_2N, Ti_4N_ (3-X) and Ti_3N_ (1.29), and the cross-section nitrides are Ti_3N_ (1.29) and TiN_ (0.3) respectively. Friction and wear tests on samples after deformation, nitriding and aging were carried out. The nitriding samples showed the best wear resistance.