基于微小型机床的微铣削( Micro-milling )技术是加工镍基高温合金微小结构/零件的可行技术手段。文章通过镍基高温合金微铣削加工实验，利用扫描电子显微镜和能谱分析仪对刀具的磨、破损形态及局部化学成分和槽的表面形貌进行了研究分析，发现镍基高温合金微铣削毛刺形貌及成因与镍基高温合金传统切削或其他材料微铣削具有很大不同：首先，毛刺长度过长；其次，刀具磨损对鳞刺的产生有很大影响；鳞刺只出现在槽的一侧边界。在实验研究基础上，分析了毛刺的成因，为后续镍基高温合金微铣削毛刺的有效抑制研究提供参考。

Micro milling technology which is based on the micro machine tool is one of the feasible skills processing the Nickel-based superalloy micro constructions/parts. Micro-milling Nickel-based superalloy tests have been carried out and then the wear/break features and the chemical component of the testing tool as well as the surface features of the testing slots have been researched. Results show that the burrs’ features and causes in micro milling Nickel-based superalloy have great differences from the traditionally milling Nickel-based superalloy and micro milling other materials. Firstly, the length of the burrs is too long. Sec-ondly, tool wearing has great effects on the scales’ formation. Thirdly, the scales only appear on the one side of the testing slots. Based on the tests and researches, formation of the burrs has been studied to provide references for controlling the burrs in micro milling Nickel-based superalloy effectively.

基于神经网络技术，根据M963铸造镍基高温合金疲劳试验数据，建立了高温合金疲劳性能预测模型，并进行了M963铸造镍基高温合金相关疲劳验证和分析。结果表明：从提高M963高温合金疲劳性能的角度出发，合金元素添加量（质量分数）优选为7％Cr＋5％V＋0．5％RE；熔体过热温度优选为1030℃；表面超音速火焰喷涂合金粉末配比优选为cr--20A1-30V-0．5Y。

According to the experimental data of fatigue test,prediction model of fatigue performance of M963 Ni-based superalloy was built by using neural network technology,and experimental validation and analysis were carried out. The results show that for improving the fatigue performance of M963 superalloy,the optimized amount of alloying elements is 7%Cr+5%V+0.5%RE;the optimized melt superheat temperature is 1 030 ℃;the optimized matching ratio of alloy powder for high-velocity oxygen fuel spraying is Cr-20Al-30V-0.5Y.

建立了一个三维模型来数值模拟激光多道搭接熔覆镍基单晶高温合金过程中的晶体生长行为和微观组织分布,并与激光熔覆镍基单晶高温合金Rene N5的实验结果进行对比。结果表明:搭接率和搭接方式直接影响搭接过程中的熔池形状,并最终影响搭接部分的晶体生长行为和微观组织分布,数值模拟结果和实验结果吻合很好。

A mathematical model was developed to compute the crystal solidification in muti-track laser powder deposition (LPD) processing of nickel-base single crystal superalloy for various processing parameters. LPD experiment with nickel-base single crystal superalloys Rene N5 conducted to verify the computational results. Results show that overlapping ratio and overlapping method have a predominate effect on molten pool geometry,which,in back,determines the crystal growth pattern and microstructure development in molten pool. The simulation results and experimental results agree well.

针对含有较多合金元素的镍基单晶高温合金熔焊焊接性能较差的问题,采用扫描电子显微镜、背散射衍射分析和显微硬度仪等手段,研究了镍基单晶高温合金DD8和钴基等轴晶K640M的氩弧焊焊接显微组织特征.结果表明,焊接后接头形成定向柱晶区、熔合区和母材区.对实验合金进行焊后热处理后发现,熔合区和定向柱晶区中γ相发生长大,且Co等元素的分布趋于均匀,焊接残余应力的存在导致个别位置出现再结晶现象.热处理前后接头内显微硬度无明显变化.

In order to solve the problem that the fusion welding performance of Ni-based single crystal superalloys containing high content of alloying elements is poor,the microstructural characteristics of Ni-based single crystal superalloy DD8 and Co-based equal-axis crystal superalloy K640M after the argon arc welding were studied with such means as scanning electron microscope (SEM),electron back scattering diffraction (EBSD)analysis and microhardness tester.The results show that three zones including the directional columnar grain zone, fusion zone and matrix zone form in the welding joint. After the post-welding heat treatment (PHT ),it is found that the γphase in both fusion zone and directional columnar grain zone grows and the distribution of such elements as Co tends to be uniform.Due to the existence of residual welding stress,the recrystallization can be observed in some area.The microhardness of welding joint before and after PHT has no obvious difference.

研究了热等静压处理对镍基铸造高温合金内部缺陷及显微组织的影响。结果表明,铸态镍基高温合金中存在大量疏松、孔洞等缺陷,合金由γ相及γ''相两相共存,γ''相的数量较多但分布不均匀,并有少量已发生团聚。1040℃×2 h热等静压处理可明显减少合金中疏松和孔洞等显微缺陷,增加强化相数量,但γ''相有少量聚集长大。1200℃×2 h下热等静压处理基本消除了合金中的疏松组织,但仍存在少量的微孔,原始的γ''相溶化并重新析出了细小的二次γ''相。

Effect of hot isostatic pressing ( HIP) treatment on microstructure of cast nickel-base superalloy was investigated .The results show that the microstructure of cast nickel-base superalloy is consisted of γphase and γ′phase which are unevenly distributed .There are a lot of defects such as gas porosity in cast nickel-base superalloy.After HIP treatment at 1040 ℃for 2 h, defects in the alloy significantly reduce and amount ofγ′phase increase, but someγ′phase grow up.After HIP treatment at 1200 ℃for 2 h, defects in the alloy almost disappeare , the original γ′phase melte and reprecipitate , but there are still a small amount of micropores .