多次激光冲击Ti-6Al-4V钛合金表面纳米化研究

发布时间：2018-06-29 08:04

本文选题：激光技术 + 纳米晶　；参考：《激光技术》2017年05期

【摘要】：为了研究激光冲击Ti-6Al-4V钛合金下的表面纳米化和微观结构的演变特性,采用短脉冲Nd∶YAG激光器对Ti-6Al-4V钛合金表面分别进行了激光冲击实验,得到了不同激光冲击次数下钛合金表面的微观组织和相应表面硬度。随着激光冲击次数增加,晶粒尺寸逐渐减小并形成纳米晶粒;冲击3次以上时,纳米晶数量明显增多、尺寸分布更加均匀,表面出现取向更加随机的等轴纳米晶;冲击5次后,随着冲击次数增加,钛合金表面纳米晶粒尺寸没有出现明显降低的趋势,始终保持50nm~130nm;不同冲击次数下纳米层的深度不会明显增加,纳米层深度约为15μm~20μm;冲击次数5次以上后,钛合金表面硬度趋于稳定,最大值约为525HV~530HV。结果表明,Ti-6Al-4V钛合金表面纳米化程度随着激光冲击次数的增加而提高;在5次激光冲击后钛合金表面的纳米化程度达到渐饱和状态,表面具有分布较好的纳米晶和较高的硬度。这表明多次激光冲击钛合金表面可以实现晶粒从微米级向纳米级转化。
[Abstract]:In order to study the surface nanocrystalline and microstructure evolution characteristics of Ti-6Al-4V titanium alloy under laser impact, laser shock experiments were carried out on the surface of Ti-6Al-4V titanium alloy using a short pulse ND: YAG laser. The microstructure and surface hardness of titanium alloy were obtained under different laser impact times. With the increase of laser shock times, the grain size gradually decreases and forms nanocrystals. When the impact is more than 3 times, the number of nanocrystals increases obviously, the size distribution is more uniform, and the surface orientation is more random. With the increase of impact times, the nanocrystalline size of titanium alloy surface did not decrease obviously, and the depth of nanocrystalline layer was not obviously increased at different impact times, and the depth of nano-layer was about 15 渭 m ~ 20 渭 m after 5 times of impact, and the depth of nanocrystalline layer was about 15 渭 m ~ (20 渭 m) after 5 times of impact. The surface hardness of titanium alloy tends to be stable, and the maximum value is about 525HVV 530HV. The results show that the surface nanocrystalline degree of Ti-6Al-4V titanium alloy increases with the increase of laser shock times, and the nanocrystalline distribution and hardness of Ti alloy surface reach saturation state after five laser shocks. The results show that the surface of titanium alloy can be transformed from micron to nanocrystalline by multiple laser impact.
【作者单位】：江苏大学机械工程学院;
【基金】：国家自然科学基金资助项目(51275556) 水利部科技推广计划资助项目(TG1521)
【分类号】：TG146.23;TG665

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