应用激光, 2015, 35 (4): 408, 网络出版: 2015-12-18  

TC4钛合金阀门的激光表面渗氮研究

Study on TC4 Titanium Alloy used as Valve by Laser Surface Nitriding
作者单位
1 苏州大学机电工程学院激光加工中心, 江苏 苏州 215021
2 苏州大学沙钢钢铁学院, 江苏 苏州 215021
3 苏州大学轨道交通学院, 江苏 苏州 215131
摘要
TC4(Ti-6Al-4V)钛合金表现出了非凡的高比强度和良好的抗氧化性能, 这使它们可用于航空航天和石油化工领域。然而, TC4较低的耐磨性, 限制了它们在摩蚀环境中的应用。在众多的表面改性技术中, 激光渗氮由于可控并且可以对指定区域渗氮处理, 对环境无污染因此受到了极大的重视。本文通过采用Nd:YAG脉冲激光对在不同比例的氮和氩的混合气体中进行TC4合金表面氮化处理, 探讨了氮气浓度等对氮化层组织和硬度的影响。结果表明, 激光合金化试样存在组织不同的三个区域, 分别为熔融区、热影响区和基材。熔融区由钛合金基体和TiN组成, 其中TiN呈现树枝晶形态, 枝晶为定向生长的柱状晶, 在熔融区的底部, 枝晶以细小的针状枝晶形式存在; 熔融区存在明显的裂纹, 这些微裂纹是由于表面受激光脉冲作用快速熔化和随后急冷凝固时产生的应力所引起的。TiN激光合金化层的硬度在600~800 HV之间, 约为TC4合金的2倍。
Abstract
TC4( Ti-6Al-4V) titanium alloys exhibit a remarkable combination of high specific strength and good oxidation resistance, which make them useful for aerospace and chemical industrial applications. However, they suffer from low wear resistance, which limits them in applications where abrasive or erosion phenomena are present. Over the last decade, various types of surface modification techniques have been developed aimed at improving the wear resistance of Ti and its alloys. Among the various surface engineering methods, laser surface nitriding is a promising method. In present paper, laser surface nit riding is carried out on the surface of TC4 alloy by Nd:YAG laser in a mixture of nitrogen and argon gases with different ratio. The influence of N2 ration on the microstructure and hardness is investigated.The results show that the nitriding zone is divided into three layers, i.e, melting zone, heat affected zone and base material. Melting zone consists of TiN in a form of dendrites. Dendrite consists of orientated growth columnar grains at the bottom, with a small dendrite dendrites existed in the form of needle-like. There are obvious micro-cracks in the melting zone, which caused by thermal stress. The stress is the result of the surface rapid melting by the laser pulse, and then solidification quenching. The microhardness of the nitriding is approximately 600~800 HV, which is 2 times of the TC4 substrate.

张敏, 严凯, 陈长军, 李洋, 王晓南, 胡增荣, 章顺虎. TC4钛合金阀门的激光表面渗氮研究[J]. 应用激光, 2015, 35(4): 408. Zhang Min, Yan Kai, Chen Changjun, Li Yang, Wang Xiaonan, Hu Zengrong, Zhang Shunhu. Study on TC4 Titanium Alloy used as Valve by Laser Surface Nitriding[J]. APPLIED LASER, 2015, 35(4): 408.

关于本站 Cookie 的使用提示

中国光学期刊网使用基于 cookie 的技术来更好地为您提供各项服务,点击此处了解我们的隐私策略。 如您需继续使用本网站,请您授权我们使用本地 cookie 来保存部分信息。
全站搜索
您最值得信赖的光电行业旗舰网络服务平台!