元素Re和W对选区激光熔化GH4169镍基合金组织及性能的影响

发布时间：2018-03-15 10:05

  本文选题：GH4169合金　切入点：微观组织　出处：《中北大学》2015年硕士论文　论文类型：学位论文

【摘要】：GH4169镍基高温合金广泛应用于发动机、涡轮盘等航空发动机重要高温部件，它要求在高温高腐蚀的环境下工作，但GH4169高温合金强化相γ"在高温下极不稳定，易转化成脆性相δ相，致使合金的综合性能降低。基于此，本文主要研究选区激光熔化GH4169镍基高温合金中添加元素Re、W并经过热处理后对合金组织以及合金高温蠕变性能、高温耐腐蚀性能进行研究。实验采用光学显微镜、SEM、XRD等对目前存在争议的δ相进行分析研究。 首先本文经过大量单道烧结线、烧结面以及烧结实体实验获得一组最佳工艺参数，获得最佳的工艺参数为：激光电流130A，扫描速度130mm/min，扫描间距0.35mm，脉冲宽度5.5ms，激光频率12Hz，，铺粉厚度0.15mm；其次在GH4169合金中分别添加不同含量的Re、 W元素,并混合均匀，利用获得的最佳工艺参数烧结规格20mm×15mm×3mm的长方体小块，并对加工成型的试样进行固溶处理与时效处理，之后再对试样分别进行高温蠕变实验与高温热腐蚀实验。分析元素Re、W对合金蠕变性能及高温热腐蚀性能的影响。 实验结果表明：1）添加元素Re、W都可以增强GH4169合金的显微硬度值，且随着元素Re、W含量的增加而增加；2）将含Re、W和未添加任何元素的GH4169合金进行固溶+时效处理，含Re元素合金的显微硬度值要高于GH4169合金的显微硬度值，而GH4169的显微硬度值要高于添加W元素合金的显微硬度值；且添加Re元素的合金热处理后含有较少的δ相，含元素W的合金与未添加任何元素的GH4169合金热处理后均有δ相和长方形状的碳化物析出3）添加元素Re的合金其蠕变寿命要高于添加W元素合金的高温蠕变寿命4）在950℃涂敷75％Na2S04+25％NaCl混合盐的同等条件下，含元素Re镍基合金的抗热腐蚀性能明显好于含元素W的镍基高温合金，未添加任何元素GH4169合金的抗热腐蚀性略好于添加元素W合金。含Re镍基合金、含W镍基合金和未添加任何元素的GH4169合金的热腐蚀进程按照硫化-氧化机理进行分析，提高合金组织均匀性和添加Re元素有益于提高合金的抗热腐蚀能力。
[Abstract]:GH4169 nickel base superalloy is widely used in engine, turbine disk and other important high temperature parts of aeroengine. It requires working in high temperature and high corrosion environment, but the strengthening phase 纬 "of GH4169 superalloy is extremely unstable at high temperature and easily converted into brittle phase 未 phase." The comprehensive properties of the alloy are reduced. Based on this, this paper mainly studies the microstructure and creep properties of the alloy after heat treatment by adding the element Rew to the selected laser melting GH4169 nickel-base superalloy. The corrosion resistance at high temperature was studied, and the 未 phase was studied by means of optical microscope (SEM) XRD and so on. First of all, a group of optimum process parameters are obtained through a large number of single-pass sintering lines, sintering surfaces and sintering solid experiments. The optimum technological parameters are as follows: laser current 130A, scanning speed 130mm / min, scanning interval 0.35mm, pulse width 5.5ms, laser frequency 12Hz, coating thickness 0.15mm.After adding different contents of Rew elements into GH4169 alloy and mixing them evenly, the optimum technological parameters are as follows: the laser current is 130A, the scanning speed is 130mm / min, the scanning distance is 0.35mm, the pulse width is 5.5ms. The cuboid block of 20mm 脳 15mm 脳 3mm was sintered with the best process parameters, and the sample was treated by solution treatment and aging treatment. Then the creep test at high temperature and the hot corrosion test at high temperature were carried out to analyze the effect of the element Rew on the creep and hot corrosion properties of the alloy. The experimental results show that the microhardness of GH4169 alloy can be enhanced by adding the element Rew, and the microhardness of the alloy increases with the increase of the content of Rew.) the solution aging treatment of the GH4169 alloy containing and without any elements is carried out. The microhardness value of re containing alloy is higher than that of GH4169 alloy, while the microhardness value of GH4169 alloy is higher than that of W element alloy, and the alloy containing re element contains less 未 phase after heat treatment. After heat treatment, 未 phase and rectangular carbide precipitate from the alloys containing W and GH4169 without any elements.) the creep life of alloys with re is higher than that of alloys with W at high temperature (4). Under the same conditions as the mixed salt of Na _ 2S _ 04 _ 25 and Na _ 2S _ 04 _ 25 coated at 950 鈩

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