共查询到18条相似文献,搜索用时 46 毫秒
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研究了DZ-22B合金800℃、5000h,900℃、3000h长期时效后显微组织和力学性能的变化试验结果与相分计算结果吻合。结果表明,长期时效后,末析出TCP相。力学性能基本稳定。 相似文献
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定向凝固和单晶高温合金及涡轮叶片的发展 总被引:6,自引:0,他引:6
北京航空材料研究所对定向凝固及单晶高温合金及工艺进行了多年卓有成效的研究,建立了先进的定向凝固设备,发展了定向凝固工艺,研制了一系列高性能定向和单晶高温合金;对合金设计、热处理、合金元素的作用进行了分析研究,为确定合适的化学成分及选定最佳工艺参数提供了可靠的基础;进行了精密铸造工艺的研究,发展了无余量铸造技术和用于定向及单晶的陶瓷型壳和型芯,并用此发展了多种航空定向和单晶叶片,特别是研制和批生产了用于先进航空发动机的DZ22无余量具有复杂内冷通道的空心涡轮叶片。现在,其主要目标是研制无余量的单晶空心叶片及其他单晶课题。 相似文献
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为研究定向凝固柱晶高温合金薄壁铸件凝固过程的热裂纹形成倾向,采用定向凝固空心薄壁管状试样,考察了Ti,Zr,Hf,Al和B等元素对定向凝固柱晶高温合金热裂倾向性的影响;采用SEM、断口分析及DSC方法,分析了热裂的晶界宏观形态.结果表明:随着Ti含量的增加,γ/γ′共晶增多,尺寸增大,合金凝固温度范围变大,定向合金的热裂倾向性严重;Zr元素含量增加,促成共晶形成,合金出现热裂纹;Hf含量的变化对合金的热裂没有影响;Al,B含量增加,微观组织无明显变化,但合金凝固温度范围变大,导致定向凝固合金出现热裂. 相似文献
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新研制的抗燃气腐蚀长寿命定向凝固合金的机械性能与Rene80,IN-378(M38),DS-Rene80等合金进行了比较,从成分,γ′相碳化物,硼化物,晶粒结构,偏析及缺陷等方面阐述了显微镜组织对机械性能的影响。 相似文献
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In the present paper there are two parts contributing to the discussion of high rate directional solidification and its application. The first part aims to characterize the high rate directional solidification of various kinds of alloys. It was found that the relevant cooling rate of the high rate directional solidification is defined to be within 1–103 K/s (solidification rate is 10-4–10-1 m/s as GL= 100 K/cm) and that it is located in the region between the near-equilibrium slow growth rate and the rapid solidification rate beyond the equilibrium condition, whilst at the same time there occurs a series of turning effects of interface stability and morphologies. With the increase in the growth velocity the interface with the plane front evolves to cells and dendrites at the stage of near-equilibrium and with a further increase in growth rate they transformed reversibly from dendrites to cell structure and then to the absolute stability of a planar interface. The change of solute segregation reveals the same from a lowsegregation, then increased and finally reduced again. An explanation based on effective constitutional supercooling about the evolution of interface morphologies with respect to the changes of growth rate is proposed.The second part is devoted to introducing experimental results for single crystal superalloys using the rate directional solidiication principle. It is shown that the single crystal superalloys CMSX–2 and NASAIR 100 exhibit significant improvement in microstructure segregation and mechanical properties at high temperature both in the as-cast and after-heat-treatment conditions with the high rate directional solidification technique. 相似文献
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In the comparison of the solidification characteristics of supercooling directional solidification (SDS) with constrained directional solidification (DS) and with the consideration of the inheritance of supercooled melt, the SDS technique established with the combination of melt supercooling and traditional DS was proposed. An exploring study on SDS techniques was also conducted using appropriate facilities, designed and manufactured by the authors’ laboratory and the deep supercooling of Cu–5.0%Ni alloy, and its DSs were implemented. 相似文献
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Alloy DZ22 possesses rather high intermediateand elevated temperature mechanical propertiescomparable with the advanced commercial DS al-loy PWA1422.The alloy composition is based onPWA1422 alloy,only the content ranges of Hf,Cand Zr are changed for systematic study.The pres-ent melting technology for master alloy ingot andDS process parameters for components are suitablefor this alloy.The alloy revert which has 相似文献
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Absract The impact of thermosolutal convection during directional solidification is explored via results of numerical investigations.
Results from fully transient numerical simulations of directional solidification in a differentially heated cavity under terrestrial
conditions and Bridgman cytstal growth in space are discussed. The pivowl role ofboth thermaland solutal convection in the solidifaction process is illustrated by examining these two cases. In particular, radical and longitudinal
macrosegregation resulting from this thermosolutal convection is discussed. 相似文献
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工业燃气轮机具有热效率高、污染低等突出优点,成为未来发电机组与大型水面舰船动力的首选设备。铸造高温合金是工业燃气轮机涡轮叶片等热端部件的关键材料,其性能和制备水平在一定程度上决定了先进燃气轮机的功率、效率、寿命等性能。本文重点综述了工业燃气轮机及其涡轮叶片用铸造高温合金材料的研究及应用现状,并对工业燃气轮机涡轮叶片用铸造高温合金及涡轮叶片制造技术的发展趋势进行了展望。未来,先进定向凝固,“材料基因工程”等技术将逐渐应用到工业燃气轮机涡轮叶片用铸造高温合金的研制中;此外,先进工业燃气轮机上定向/单晶高温合金的应用将越来越广泛。 相似文献
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