The effects of boron addition on the microstructure stability and mechanical properties of a Ni-Cr based superalloy

IMR OpenIR

	The effects of boron addition on the microstructure stability and mechanical properties of a Ni-Cr based superalloy
	Yang, F; Hou, JS; Gao, S; Wang, CS; Zhou, LZ; Zhou, LZ (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China.
	2018-02-07
发表期刊	MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
ISSN	0921-5093
卷号	715 页码:126-136
摘要	This study is focused on the effect of boron additions on the microstructure stability and mechanical properties of a Ni-Cr based superalloy designed for application of 700 degrees C advanced ultra-supercritical units component. The results show that boron in the content range of 25-75 ppm has no obvious influence on as-cast and heat-treated microstructure characteristics compared with that of the alloy without boron. During long-term thermal exposure, the variation of B content has no obvious effect on gamma" coarsening, delta phase precipitation and MC carbide degeneration, but inhibits the agglomeration of M23C6 carbide along grain boundary. According to the mechanical property analysis, the boron additions contribute to mainly tensile ductility especially the elongation of whether the heat treated alloy or the long-term thermal exposed alloy. The strength especially yield strength of the B doped alloy almost keeps the same level as that of the B-free alloy. Furthermore, the SEM fractography shows a change from intergranular fracture to a mixed fracture and the dimples on fracture surface obviously increase with the addition of boron. The mechanism discussion reveals that the segregation of boron at grain boundary resulted in the improvement of grain boundary cohesion and the optimization of carbides distribution at grain boundary. The strengthening mechanism of delta phase is confirmed as its obstacle effect to dislocation movement.; This study is focused on the effect of boron additions on the microstructure stability and mechanical properties of a Ni-Cr based superalloy designed for application of 700 degrees C advanced ultra-supercritical units component. The results show that boron in the content range of 25-75 ppm has no obvious influence on as-cast and heat-treated microstructure characteristics compared with that of the alloy without boron. During long-term thermal exposure, the variation of B content has no obvious effect on gamma" coarsening, delta phase precipitation and MC carbide degeneration, but inhibits the agglomeration of M23C6 carbide along grain boundary. According to the mechanical property analysis, the boron additions contribute to mainly tensile ductility especially the elongation of whether the heat treated alloy or the long-term thermal exposed alloy. The strength especially yield strength of the B doped alloy almost keeps the same level as that of the B-free alloy. Furthermore, the SEM fractography shows a change from intergranular fracture to a mixed fracture and the dimples on fracture surface obviously increase with the addition of boron. The mechanism discussion reveals that the segregation of boron at grain boundary resulted in the improvement of grain boundary cohesion and the optimization of carbides distribution at grain boundary. The strengthening mechanism of delta phase is confirmed as its obstacle effect to dislocation movement.
部门归属	[yang, fei ; hou, jieshan ; gao, shuang ; wang, changshuai ; zhou, lanzhang] chinese acad sci, inst met res, shenyang 110016, liaoning, peoples r china ; [yang, fei] univ sci & technol china, sch mat sci & engn, hefei 230026, anhui, peoples r china
关键词	Service-exposed Alloy-625 Boiler Applications Room-temperature Behavior Phase Polycrystalline 650-degrees-c Precipitation Evolution Fracture
学科领域	Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
资助者	National Energy Administration Program of China [NY20150102]; National Key Research and Development Program of China [2017YFB0305204]; National Natural Science Foundation of China [51571191]
收录类别	SCI
语种	英语
WOS记录号	WOS:000426231700015
引用统计	被引频次：20[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/79515
专题	中国科学院金属研究所
通讯作者	Hou, JS; Zhou, LZ (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China.
推荐引用方式 GB/T 7714	Yang, F,Hou, JS,Gao, S,et al. The effects of boron addition on the microstructure stability and mechanical properties of a Ni-Cr based superalloy[J]. MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING,2018,715:126-136.
APA	Yang, F,Hou, JS,Gao, S,Wang, CS,Zhou, LZ,&Zhou, LZ .(2018).The effects of boron addition on the microstructure stability and mechanical properties of a Ni-Cr based superalloy.MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING,715,126-136.
MLA	Yang, F,et al."The effects of boron addition on the microstructure stability and mechanical properties of a Ni-Cr based superalloy".MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING 715(2018):126-136.