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激光冲击强化高温失效机理与稳固方法研究
Alternative TitleStudy on High Temperature Failure Mechanism and Stabilization Method of Laser Shock Peening
胡太友1,2
Department工艺装备与智能机器人研究室
Thesis Advisor乔红超
Keyword温激光冲击强化 GH4169合金 热稳定性 残余应力 微观组织结构
Pages67页
Degree Discipline机械制造及其自动化
Degree Name硕士
2019-05-17
Degree Grantor中国科学院沈阳自动化研究所
Place of Conferral沈阳
Abstract本论文以镍基高温合金GH4169材料为研究对象,设计了一款WLSP实验平台,通过显微硬度、表面粗糙度、残余应力、TEM等表征指标,对比研究了LSP和WLSP的热稳定性。取得的主要结果如下:(1)设计并制作了一款WLSP实验平台。以实验平台的功能需求为出发点,然后通过查阅相关资料,拟定了相应的解决方案,最后进行了零件的加工与平台的搭建。该平台主要具备加热控温功能、防试样表面氧化功能、约束层稳定输出与循环功能和快速定位夹紧功能。(2)研究了激光冲击强化GH4169合金的热稳定性。首先以表面显微硬度为表征指标,研究了不同激光能量(3J、4J、5J、6J、7J)和不同冲击次数(1次、2次、3次、4次)下的LSP效果。结果表明,当激光能量为7J,冲击2次时,试样表面显微硬度最大为476.9HV,较基体硬度(376.3HV)增加了26.7%,所以选择7J、2次作为最优的实验参数进行后续的热稳定性研究。以表面残余应力和微观组织结构变化为表征指标,研究了不同时效温度(600℃、650℃、700℃)和不同时效时间(1h、3h、5h、10h、30h、100h)下激光冲击强化GH4169合金的热稳定性。结果表明,随着时效时间和时效温度的增大,LSP试样表面残余应力松弛幅度逐渐增大,位错密度逐渐减小,γ"相逐渐聚集粗化并转变为δ相。(3)研究了温激光冲击强化GH4169合金的热稳定性。首先以表面显微硬度、表面粗糙度和表面残余应力为表征指标,研究了不同工艺温度(100℃、150℃、200℃、250℃、300℃、350℃)下的WLSP效果,结果表明,当工艺温度为200℃时,强化效果最佳。试样经过WLSP(200℃)处理后,材料内部生成了高密度位错缠结,形成了位错网络、位错胞等复杂的位错结构。随后以表面残余应力和微观组织结构变化为表征指标,研究了不同时效温度和时效时间下温激光冲击强化GH4169合金的热稳定性。结果表明,与LSP相比,WLSP试样表面残余应力松弛量和松弛速率较小,材料内部位错密度更高、更加均匀,且无明显的δ相析出,具有更高的热稳定性。
Other AbstractIn this thesis, a nickel-based superalloy GH4169 material was used as the research object, and a temperature laser shock strengthening experimental platform was designed , and the thermal stability of LSP and WLSP were compared by microhardness, surface roughness, residual stress and TEM. The main results obtained are as follows: (1) A warm laser shock enhancement experimental platform was designed and fabricated. Taking the functional requirements of the experimental platform as the starting point, and then formulating the corresponding solutions by consulting relevant materials, and finally processing the parts and building the platform. The platform is mainly equipped with heating and temperature control function, anti-oxidation function of sample surface, confining layer stable output and loop function and quick positioning and clamping function. (2) The thermal stability of LSP GH4169 alloy was studied. Firstly, the LSP effect of different laser energies (3J, 4J, 5J, 6J, 7J) and different impact times (1, 2, 3, 4 times) was studied by using the surface microhardness as a characterization index. The results show that when the laser energy is 7J and the impact is 2 times, the microhardness of the sample surface is 476.9HV, which is 26.7% higher than the matrix hardness (376.3HV), so 7J and 2 times are selected as the optimal experimental parameters for subsequent thermal stability studies. The thermal stability of GH4169 alloy of different aging temperatures (600 °C, 650 °C, 700 °C) and different aging time (1h, 3h, 5h, 10h, 30h, 100h) was studied by using the changes of surface residual stress and microstructure as indicators. The results show that with the increase of aging time and aging temperature, the residual stress relaxation on the surface of LSP samples increases gradually, the dislocation density decreases gradually, and the γ phase gradually aggregates and becomes coarse and transforms into δ phase. (3) The thermal stability of WLSP GH4169 alloy was studied. Firstly, the WLSP effect of different process temperatures (100 °C, 150 °C, 200 °C, 250 °C, 300 °C, 350 °C) was studied by using the surface microhardness, surface roughness and surface residual stress as indicators. The results show that the strengthening effect is best when the process temperature is 200 °C. After the sample is processed by WLSP (200 °C), high-density entanglement is formed inside the material, which forms a complex dislocation structure such as dislocation network and dislocation cell. Then the thermal stability of WLSP GH4169 alloy under different aging temperature and aging time was studied by using surface residual stress and microstructure change as indicators. The results show that compared with LSP, the surface residual stress relaxation and relaxation rate of WLSP samples are smaller; the internal dislocation density of materials is higher and more uniform, and there is no obvious δ phase precipitation , which has higher thermal stability.
Language中文
Contribution Rank1
Document Type学位论文
Identifierhttp://ir.sia.cn/handle/173321/25187
Collection工艺装备与智能机器人研究室
Affiliation1.中国科学院沈阳自动化研究所
2.中国科学院大学
Recommended Citation
GB/T 7714
胡太友. 激光冲击强化高温失效机理与稳固方法研究[D]. 沈阳. 中国科学院沈阳自动化研究所,2019.
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