Microstructure evolution of a Ni–Cr–W superalloy during long-term aging at high temperatures
Microstructure evolution of a Ni–Cr–W superalloy during long-term aging at high temperatures
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DOI：
10.1016/j.matchar.2015.06.018
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发表时间：
2015-08
影响因子：
4.7
通讯作者：
H. Lee;Hyunmyung Kim;Donghoon Kim;C. Jang
中科院分区：
文献类型：
--
作者：
H. Lee;Hyunmyung Kim;Donghoon Kim;C. Jang
研究了Ni-Cr-W高温合金（230合金）长期暴露于高温（800和900 °C，长达20，000 h）对组织演变的影响。在800 °C长期时效后，观察到大量的二次富Cr M23 C6碳化物析出。此外，还观察到富W初生η-M6 C碳化物的内部分解，如富W M6 C → α-W、富Cr M23 C6和贫W Ni基基体。在900 °C长期时效后，在部分区域出现了富Cr、Ni相和α-W相的析出，而二次富Cr的M23 C6碳化物则大量减少。同时，在900 °C下，初生M6 C碳化物的解离不太显著。在两种温度下长期老化导致拉伸伸长率降低，而在900 °C下老化后强度增加最小。拉伸性能的降低与富Cr的M23 C6碳化物、富Cr和Ni的析出相以及α-W相的演变有关，而与初生M6 C碳化物的演变无关。
The effects of long-term exposure to high temperature (800 and 900 °C for up to 20,000 h) on the microstructure evolution of a Ni–Cr–W superalloy (Alloy 230) were investigated. After long-term aging at 800 °C, extensive precipitation of the secondary Cr-rich M23C6carbides was observed. In addition, the internal dissociation of W-rich primary η-M6C carbides was observed, such as, W-rich M6C → α-W, Cr-rich M23C6, and W-depleted Ni-base matrix. After long-term aging at 900 °C, precipitation of Cr- and Ni-rich phase and α-W phase was observed in some areas at the expense of the secondary Cr-rich M23C6carbides. Meanwhile, the dissociation of the primary M6C carbides was less significant at 900 °C. Long-term aging at both temperatures resulted in a decrease in tensile elongation while an increase in strength was minimal after aging at 900 °C. The degradation of tensile property depended on the evolution of Cr-rich M23C6carbides, Cr- and Ni-rich precipitates, and α-W phases but not on the primary M6C carbides.