Acta Metallurgica Sinica (English Letters) ›› 2006, Vol. 19 ›› Issue (2): 151-156 .

• 论文 • 上一篇    

Study on Improving the Surface Hardness of TiAl Alloy by Laser Nitriding In an Atmospheric Ambient

杨玉玲   

  1. 东北大学理学院326信箱
  • 收稿日期:2005-09-28 修回日期:1900-01-01 出版日期:2006-04-25 发布日期:2009-10-10
  • 通讯作者: 杨玉玲 张多

IMPROVING THE SURFACE PROPERTY OF TC4 ALLOY BY LASER NITRIDING AND ITS MECHANISM

Y.L. Yang, G.J. Zhao, D. Zhang,,,,   

  1. 东北大学理学院326信箱
  • Received:2005-09-28 Revised:1900-01-01 Online:2006-04-25 Published:2009-10-10

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摘要： 本文采用大气气氛下的激光氮化方法对钛合金表面进行了氮化处理以改善其表面性能。实验过程中，激光功率密度为6.5×105 w.cm-2，激光扫描速度为100mm.min-1。为了加快氮化速度以防止氧化，在氮化处理前，氮气首先被预热到300°C。利用X射线衍射方法对氮化处理后的样品进行了成分分析，并对其表面硬度进行相关测试。结果表明，在合适的工艺参数下，氮化处理后，样品表面生成了TiN 和 Ti2N，但主要成分是TiN。氮化处理后，样品表面的硬度从原始的269 Kg.mm-2 提高到了 794Kg.mm-2，表面硬度提高了3倍左右。

关键词: 激光氮化, 表面硬度, 钛合金, X射线衍射

Abstract: The mixing technology of laser and heated nitrogen was applied to improve the surface hardness of titanium alloy (TC4). The samples were nitrided with laser power density of 6.5×105W·cm-2, the scanning speed various from 100 to 500mm·min-1. The nitrogen gas was pre-heated to 300℃ to accelerate the nitriding process. Some interested samples were tested with XRD method (X-ray diffraction) to analyze the composition of nitrides, and the surface hardness of HV was measured. The results show that TiN and Ti2N were formed on the surface of Ti alloy with proper nitriding parameters, but TiN is the main composition. The surface hardness increased by three times, which is from the original value of 269 to 794kg·mm-2. The mechanism of the mixing technology is considered mainly of the activation of nitrogen by laser power and the pre-heated process which accelerated the nitriding process. The nitridation process can be considered as six steps given in detail. The result by analyzing the mechanism of improving the surface property of TiAl alloy shows the improvement of surface property due to two factors: the first reason is the result of laser annealing, and the second one is the formation of TiN.

Key words: laser nitridation, surface property, Ti alloy