通过热力学模拟软件Thermo-calc优化合金成分,结合实验研究,开发了一种在750℃环境中工作的新型镍基气阀合金LF8.计算结果表明:随Cr含量增加,γ'相稍有增加,碳化物由M7C3转变为M23 C6;Ti含量超过4.5％时合金中有大量η相生成.实验研究结果表明:合金热处理后的主要析出相为γ'、Cr23 C6和TiC,γ'相呈近球形,细小弥散分布在晶内,尺寸为20 nm;Cr23 C6大部分在晶界处不连续分布,呈椭圆或者点状,尺寸为400～800 nm;TiC在晶内或者晶界附近呈块状分布,以初生TiC为主.通过优化合金成分开发的LF8气阀合金室温和高温强度以及硬度均高于Nimonic 80A,有希望成为750℃气阀合金的备选材料.
A new type of nickel-based valve alloy LF8 which could be used in the environment of 750 ℃ was developed by combining the software Thermo-calc to optimize the composition of the alloy with experimental research.The results show that with the increasing of content of Cr,γ'precipitates increases slightly and carbides change from M7C3 to M23 C6.There will be a large number of η phase to precipitate in the alloy when the content of Ti increase to more than 4.5％.The results show that the main precipitates of the alloy after heat treatment are γ',Cr23 C6 and TiC phases.γ'phases are nearly spherical,uniformly distributed in the crystal,and grain size is about 20 nm;discontinuous Cr23C6 carbides are homogeneously distributed in grain boundaries,oval or point,and grain size is 400 to 800 nm.TiC is distributed in the crystal or grain boundaries,with the primary TiC as the main component.The room temperature and high temperature strength and hardness of the LF8 valve alloy developed by optimizing the alloy composition are higher than that of the Nimonic 80A,which is expected to be an alternative material for 750 ℃ valve alloy.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%