Effect of heat treatment on the microstructure of a Ni-Fe based superalloy for advanced ultra-supercritical power plant applications

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• 作者：Xinbao Zhao ; ^{zhaoxinbao@tpri.com.cn" class="auth_mail" title="E-mail the corresponding author} ; Yingying Dang ; Hongfei Yin ; Jintao Lu ; Yong Yuan ; Zhen Yang ; Jingbo Yan ; Yuefeng Gu
• 关键词：Ultra-supercritical power plant ; Ni&ndash ; Fe based superalloy ; Heat treatment ; Microstructure ; Microhardness
• 刊名：Progress in Natural Science
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：26
• 期：2
• 页码：204-209
• 全文大小：2974 K

文摘

The effect of heat treatment on the microstructure and microhardness of a Ni–Fe based superalloy for 700 °C advanced ultra-supercritical coal-fired power plants was investigated. Results showed that the main phases in the alloy were γ, γ′, MC and M₂₃C₆, and no harmful phase was observed in the alloy. M₂₃C₆-type carbides discretely distributed nearby grain boundaries as the alloy was aged at above 840 °C. The microhardness decreased with increasing aging temperature. The coarsening of γ′ led to the increment of microhardness at 780 °C and 810 °C for a short aging time, and a significant decrease in microhardness after aging at 840 °C. The aging temperature had more significant role on the microstructure than holding time. Therefore, to obtain optimum strengthening effect for this alloy, the aging temperature should not exceed 810 °C.