Modification of Alloy 706 for High Temperature Steam Turbine Rotor Application
Modification of Alloy 706 for High Temperature Steam Turbine Rotor Application
复制标题
高温汽轮机转子应用合金 706 的改性
DOI：
10.7449/2005/superalloys_2005_77_86
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Tatsuya Takahashi
中科院分区：
文献类型：
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作者：
S. Imano;Hiroyuki Doi;K. Kajikawa;Tatsuya Takahashi
�为了提高706合金在700C以下的组织稳定性和避免Nb的偏析，我们改变了合金的化学成分。706合金由γ‘(Ni3Al)相和γ’‘(Ni3Nb)相强化。但长期暴露后，这些相在高温下不稳定，并转变为富Nb的δ或η相。变质合金(FeNiX-700)的Nb含量比706合金少，Al含量高，因此只有γ‘(Ni3Al)相强化。在700℃蠕变时效后，未发现δ或η相，室温至700℃拉伸强度与706合金基本相同。FeNIX-700合金的室温屈服强度略低于706合金，但与706合金高温屈服强度相当。FeNIX-700合金在室温至700℃温度范围内的抗拉强度和屈服强度均高于700℃时效后的706合金。根据104h级蠕变试验，Fenix-700合金在700℃下的约105h蠕变强度大于100 MPa。在本文中，我们使用力学试验、透射电子显微镜观察、偏析试验和热力学计算结果来说明Fenix-700在高温汽轮机应用中的机械性能和优势。
�To improve microstructure stability at temperatures up to 700°C and avoid segregation of Nb , we modified the chemical composition of Alloy706. It is known that Alloy706 is strengthened by γ’(Ni3Al) phase and γ’’(Ni3Nb) phase. But these phases are unstable at high temperatures after long-term exposure and transform into Nb rich δ or η phase. The modified alloy (FENIX-700) contains less Nb and more Al than Alloy706, so it is strengthened only by γ’(Ni3Al) phase. Also, we could not find δ or η phase in the FENIX-700 after creep and aging at 700°C. The tensile strengths of the FENIX-700 at temperatures from room temperature to 700°C are almost the same as that of Alloy706. The yield strength of FENIX-700 at room temperature is slightly lower than that of Alloy706, but equivalent to that of Alloy706 at high temperatures. The tensile and yield strengths of FENIX-700 at temperatures from room temperature to 700°C are higher than that of Alloy706 after aging at 700°C. According to 10 4 h class creep tests, the approximate 10 5 h creep strength of FENIX-700 at 700°C is more than 100MPa. In this presentation, we use mechanical testing, TEM observation, a segregation test and thermodynamics calculation results to show the mechanical properties and advantages of FENIX-700 for high temperature steam turbine applications.