M2C and M6C carbide precipitation in Ni-Mo-Cr based superalloys containing silicon
M2C and M6C carbide precipitation in Ni-Mo-Cr based superalloys containing silicon
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Ni-Mo-Cr基含硅高温合金中M2C和M6C碳化物的析出
DOI：
10.1016/j.matdes.2016.09.075
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发表时间：
2016-12-15
影响因子：
8.4
通讯作者：
Zhou, Xing-Tai
中科院分区：
文献类型：
--
作者：
Jiang, Li;Zhang, Wen-Zhu;Zhou, Xing-Tai
研究了硅对Ni-Mo-Cr基合金铸态和变形态一次碳化物和二次晶界碳化物的影响。随着铸态合金中Si含量的增加，晶界处的片状M2 C共晶碳化物被枝晶间的片状M6 C共晶碳化物所取代。将不同Si含量的变形合金分别在750 ℃下热暴露1、500和2000 h。可以观察到，在低Si合金（0.051和0.188重量%）中，在晶界处形成的初始M2 C碳化物被M6 C碳化物取代。随着曝光时间的增加。在0.562wt.%的合金中，只有M6 C碳化物在晶界处析出Si，在热暴露期间粗化。高硅合金在2000 h热暴露后，除M_2C型碳化物的异常形成外，也存在类似的趋势。根据经典形核理论，Si对碳化物类型的影响归因于M2 C碳化物和M6 C碳化物之间的竞争形核。(C)2016爱思唯尔有限公司版权所有
The effect of silicon additions on the primary carbides and second grain boundary carbides has been investigated in as-cast and wrought Ni-Mo-Cr based alloys, respectively. With the increase of Si content in the as-cast alloys, the lamellar M2C eutectic carbides at grain boundaries were replaced by skeleton-shape M6C eutectic carbides in interdendritic regions. The wrought alloys with different Si contents were thermal exposed at 750 degrees C for 1, 500 and 2000 h, respectively. It can be observed that the initial M2C carbides formed at grain boundaries were replaced by M6C carbides in the low-Si alloys (0.051 and 0.188 wt.%) with the increase of exposure time. Only M6C carbides precipitated at grain boundaries in the alloy with 0.562wt.% Si, which coarsened during the thermal exposure. Similar trends also existed in the high-Si alloy except an abnormal formation of M2C carbides after 2000 h' exposure. The effect of Si additions on the types of carbides was attributed to competitive nucleation between M2C carbides and M6C carbides based on classical nucleation theory. (C) 2016 Elsevier Ltd. All rights reserved.