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为研究高铌高磷GH4169C高温合金在高温长期时效过程中的组织稳定性,通过场发射扫描电镜和数显布氏硬度计对GH4169和GH4169C两合金分别经600、650、704及720℃时效30~10000 h的显微组织和硬度变化进行对比分析.结果表明:在服役温度(650℃)范围内长期时效,GH4169合金和GH4169C合金均表现优异的稳定性;在服役温度以上长期时效,GH4169合金和GH4169C合金稳定性较差,短时间内,合金组织就出现失稳.对比而言,704℃时GH4169C合金组织稳定性较GH4169合金高,而720℃时GH4169C合金组织稳定性劣于GH4169合金.分析认为,GH4169C合金由于提高Nb含量和P含量使的γ’相稳定性增加,得以在服役温度以上(704℃)表现比GH4169合金更为优异的组织稳定性,但Nb含量的提高也引起δ相含量的增加,导致组织稳定性下降.在超高温(720℃)下,GH4169C合金稳定性劣于GH4169合金.由此推知,相比GH4169合金,改型GH4169C合金在使用温度上有所提高,但提高有限,在超高温下,其稳定性反而降低.
In order to study the microstructure stability of GH4169C superalloy with high niobium content during long-term aging at high temperature, the GH4169 and GH4169C alloys were annealed at 600, 650, 704 and 720 ℃ for 30 ~ 10000 h.The results show that GH4169 alloy and GH4169C alloy exhibit excellent stability at the service temperature (650 ℃) for long-term aging, while GH4169 alloy And GH4169C alloy, the instability appeared in a short period of time.In contrast, the microstructure stability of GH4169C alloy was higher than that of GH4169 alloy at 704 ℃, while the stability of GH4169C alloy at 720 ℃ was inferior to that of GH4169 alloy. The results show that the γ4 phase stability of GH4169C alloy is better than that of GH4169 alloy at the temperature above service temperature (704 ℃) due to the increase of Nb content and P content. However, the increase of Nb content also causes the increase of δ The phase stability of GH4169C alloy is worse than that of GH4169 alloy at high temperature (720 ℃), suggesting that compared with GH4169 alloy, Has the temperature increased, but the increase is limited, at ultra-high temperature, but lower the stability.