| 题名 | 薄壁钛合金激光冲击强化工艺与形貌研究 |
| 作者 | 槐艳艳 |
| 学位类别 | 硕士 |
| 答辩日期 | 2017-05-24 |
| 授予单位 | 中国科学院沈阳自动化研究所 |
| 授予地点 | 沈阳 |
| 导师 | 赵吉宾 |
| 关键词 | 激光冲击强化 TC17钛合金 表面完整性 |
| 其他题名 | Investigation of laser shock processing on process and morphology of thin-wall titanium alloy |
| 学位专业 | 机械制造及其自动化 |
| 中文摘要 | 钛合金是飞行器和飞行器动力制造领域关键零部件的重要材料，疲劳是影响其服役寿命的主要因素，TC17是我国自主研发的高强度钛合金，高强度钛合金的疲劳性能对表面完整性十分敏感。研究激光冲击强化是提高抗疲劳的重要手段，相比传统改性技术特点显著，在航空领域有非常大的应用前景，且随着对高推重比的追求，航空领域大量应用薄壁结构件，对零件的性能提出了更高的要求。目前对厚度小于4mm的薄壁结构件的研究较少，因此，本文以TC17钛合金薄壁结构件为研究对象，探讨激光冲击强化对钛合金薄壁结构件的作用机制及影响规律，以寻求获得高质量的表面改性层。取得的主要结果如下：（1）对激光冲击过程中的关键过程：冲击波的产生及在金属零件中的传播、衰减、反射进行了分析。对吸收层和约束层的选择进行了分析和计算。对搭接处理中的光斑搭接方案进行了分析，对不同搭接区域所受的冲击次数提出了评价准则，并以此对不同的搭接方案的冲击次数的均匀性进行了评估，以冲击次数均匀性为目标函数，对搭接方案进行了优化，并以此作为文章实施激光冲击实验的搭接方案。（2）采用Taylor Hobson Surtronic 3+系列表面粗糙度仪、ZYGO公司的NewView5022型表面轮廓仪、PROTO公司的LXRD型大功率X射线应力分析仪、JEM-2100UHR型透射电子显微镜、HV-1000型显微硬度计等对冲击强化前和冲击强化后的所有试件的表面完整性表征参数表面粗糙度、三维轮廓、残余应力、显微组织等进行了测试。（3）对工艺参数激光能量和光斑密度对表面粗糙度、三维轮廓、显微硬度的影响规律进行了分析研究，对冲击后的零件表面显微组织进行了观察。（4）对残余应力结果进行量化分析，激光能量和光斑密度以及二者的交互作用对残余应力都有显著影响，冲击后零件表面不再各项同性，竖直方向的残余应力大于水平方向的残余应力。以实验结果为响应，用响应面法对残余应力进行了回归分析和预测。 |
| 英文摘要 | For Titanium alloy plays important role in aerospace key components manufacturing field and the service life is mainly decided by fatigue life. TC17 titanium alloy was developed by our country which has a high strength and sensitive to surface integrity. The fatigue performance of high strength titanium alloy is very sensitive to surface integrity. Laser shock processing (LSP) is an effective method to improve the fatigue life of components. And LSP has significant advantages compared with the traditional surface processing technologies so it plays irreplaceable role especially in aerospace industry. With the pursuit of high thrust-weight ratio, a large number of thin-walled structure components are applied in the field of aerospace that has put forward a higher demand to the material properties. At present the research of LSP on components with thickness less than 4mm is still limit, therefore the mechanism and influence of processing parameters of LSP on thin-walled structure components was discussed in order to obtain high quality surface. The main results as follows: （1）The key process of LSP: the generation of shock waves, the propagation, attenuation and reflection in the pieces were analyzed. The selection of absorption layer and confinement layer were analyzed and calculated. The overlap programs of laser spot were analyzed and an evaluation criterion was putted forward basing on scan times. The program was optimized and the experiments were implemented. （2） The surface roughness, residual stress, three-dimension profile, micro-hardness and microstructure of all spices before and after LSP were conducted by using a Taylor Hobson Surtronic 3+ series surface roughness meter, a NewView5022 surface profiler of ZYGO, a LXRD high power X-ray stress analyzer of PROTO, a micro-hardness tester of HV-100 and a transmission electron microscopy of JEM-2100HR. （3）The effect of laser energy and pulse density on surface roughness, three-dimension profile and micro-hardness was analyzed and the microstructure after LSP was observed. （4）The residual stress was analyzed quantitatively. Laser energy, pulse density and the interaction between them all have significant effect on residual stress. The material was no longer homogeneous and the residual stress in vertical direction is larger than that in horizon direction. The residual stress was also predicted by response surface method. |
| 语种 | 中文 |
| 产权排序 | 1 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.sia.cn/handle/173321/20512]  |
| 专题 | 沈阳自动化研究所_装备制造技术研究室 |
| 推荐引用方式 GB/T 7714 | 槐艳艳. 薄壁钛合金激光冲击强化工艺与形貌研究[D]. 沈阳. 中国科学院沈阳自动化研究所. 2017. |
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