Microstructure stability and mechanical properties of a new low cost hot-corrosion resistant Ni-Fe-Cr based superalloy during long-term thermal exposure

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	Microstructure stability and mechanical properties of a new low cost hot-corrosion resistant Ni-Fe-Cr based superalloy during long-term thermal exposure
	W.; Qin Sun, X. Z.; Guo, J. T.; Lou, L. H.; Zhou, L. Z.
	2015
发表期刊	Materials & Design
ISSN	0261-3069
卷号	69 页码:70-80
摘要	A new low cost hot-corrosion resistant Ni-Fe-Cr based superalloy is designed and fabricated. The microstructure evolution, mechanical properties and effect of minor Cr variation on the microstructure stability during long-term thermal exposure have been investigated in details. Microstructure observations reveal that the new Ni-Fe-Cr based superalloy is constituted of gamma matrix, gamma' precipitate, primary MC carbide and grain boundary (GB) M23C6 carbide after standard heat treatment. During long-term thermal exposure at 850 degrees C, the gamma' precipitate coarsens greatly within 3000 h, which significantly degrades the room temperature hardness and stress-rupture life at 800 degrees C/294 MPa. The primary MC degenerates gradually by reactions of MC + gamma -> M23C6 + gamma', MC + gamma -> M23C6 + M6C + gamma' and MC + gamma -> M23C6 + M6C + eta, respectively. The growth of carbide and gamma' along GB changes it from thin discontinuous chain structure to coarse continuous chain structure, which might lead to the intergranular fracture during stress-rupture. In addition, small amount of grain interior (GI) M23C6 carbide precipitates in the matrix, which has negligible influence on the stress-rupture property. Moreover, minor increase of Cr content (from 20% to 21%) extends the precipitating temperature range of sigma phase and enhances its precipitating peak temperature, which results in a large amount of r phase precipitates in the Ni-Fe-Cr based superalloy during long-term thermal exposure at 850 degrees C. The formation of sigma phase increases the room temperature hardness but degrades the stress-rupture life and elongation of the Ni-Fe-Cr based superalloy greatly. (C) 2014 Elsevier Ltd. All rights reserved.
部门归属	[sun, wen] univ sci & technol china, hefei 230022, peoples r china. [sun, wen ; qin, xuezhi ; guo, jianting ; lou, langhong ; zhou, lanzhang] chinese acad sci, inst met res, shenyang 110016, peoples r china. ; qin, xz (reprint author), chinese acad sci, inst met res, shenyang 110016, peoples r china. ; xzqin@imr.ac.cn
关键词	Nickel Superalloy Thermal Exposure Microstructure Stability Mechanical Properties Cr Addition Single-crystal Superalloy Service Exposure Mu Phase Precipitation Alloy Behavior Evolution Carbides Rupture
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/73925
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	W.,Qin Sun, X. Z.,Guo, J. T.,et al. Microstructure stability and mechanical properties of a new low cost hot-corrosion resistant Ni-Fe-Cr based superalloy during long-term thermal exposure[J]. Materials & Design,2015,69:70-80.
APA	W.,Qin Sun, X. Z.,Guo, J. T.,Lou, L. H.,&Zhou, L. Z..(2015).Microstructure stability and mechanical properties of a new low cost hot-corrosion resistant Ni-Fe-Cr based superalloy during long-term thermal exposure.Materials & Design,69,70-80.
MLA	W.,et al."Microstructure stability and mechanical properties of a new low cost hot-corrosion resistant Ni-Fe-Cr based superalloy during long-term thermal exposure".Materials & Design 69(2015):70-80.