CRACK INITIATION AND PROPAGATION AROUND HOLES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY DURING THERMAL FATIGUE CYCLE

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	CRACK INITIATION AND PROPAGATION AROUND HOLES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY DURING THERMAL FATIGUE CYCLE
	Wang Li 2; Zhou Zhongjiao 2; Zhang Shaohua 2; Jiang Xiangdong 1; Lou Langhong 2; Zhang Jian 2
刊名	ACTA METALLURGICA SINICA
	2015-10-11
卷号	51 期号:10 页码:1273-1278
关键词	Ni-based single crystal superalloy crystal orientation thermal fatigue hole crack initiation and propagation
ISSN号	0412-1961
通讯作者	Wang Li(wangli@imr.ac.cn)
英文摘要	Ni-based single crystal (SX) superalloys are widely used for production of blades in gas turbines and aircraft engines for their superior mechanical performance at high temperatures. To obtain high cooling efficiency, most of the SX blades consist of thin wall with cooling holes. However, thermal fatigue cracks are usually observed in blades with this kind of structures. Thus, it must be valuable to investigate the crack initiation and propagation around a hole during thermal fatigue tests in a SX superalloy. In the present work a second generation SX Ni-based superalloy was used. Plate specimens that parallel to directional solidification (DS) direction and along (100) or (110) planes were prepared. A hole with diameter of 0.5 mm was drilled vertical to the surface in the middle of the plate by electro-discharge machining (EDM). Thermal fatigue tests were performed between room temperature and 1100 degrees C. Effect of crystal orientation on the crack initiation and propagation was investigated and the reasons were analyzed. It was found that a thin recast layer was produced around holes of EDM drilled. The thickness of the recast layer was 15 mu m in the maximum. Crystal orientation has great effect on the crack initiation sites and propagation kinetics. After 80 cyc thermal fatigue tests, in (110) specimens cracks initiated at the edge of the holes that vertical to the DS direction, then grew quickly and propagated along directions about 45 degrees from the DS direction. After 200 cyc tests, cracks developed to more than 2 mm in length. While in (100) specimens no cracks could be observed even after 200 cyc thermal fatigue tests. This difference was mainly due to the combined effects of different thermal stress caused by the anisotropy of single crystals and of the microstructure characteristics.
资助项目	National Natural Science Foundation of China[51201164] ; National High Technology Research and Development Program of China[2012AA03A511] ; National Key Scientific Instrument and Equipment Development Project[2012YQ22023304]
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000363997600012
资助机构	National Natural Science Foundation of China ; National High Technology Research and Development Program of China ; National Key Scientific Instrument and Equipment Development Project
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/121075]
专题	金属研究所_中国科学院金属研究所
通讯作者	Wang Li
作者单位	1.Beijing Beiye Funct Mat Corp, Beijing 100192, Peoples R China 2.Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Wang Li,Zhou Zhongjiao,Zhang Shaohua,et al. CRACK INITIATION AND PROPAGATION AROUND HOLES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY DURING THERMAL FATIGUE CYCLE[J]. ACTA METALLURGICA SINICA,2015,51(10):1273-1278.
APA	Wang Li,Zhou Zhongjiao,Zhang Shaohua,Jiang Xiangdong,Lou Langhong,&Zhang Jian.(2015).CRACK INITIATION AND PROPAGATION AROUND HOLES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY DURING THERMAL FATIGUE CYCLE.ACTA METALLURGICA SINICA,51(10),1273-1278.
MLA	Wang Li,et al."CRACK INITIATION AND PROPAGATION AROUND HOLES OF Ni-BASED SINGLE CRYSTAL SUPERALLOY DURING THERMAL FATIGUE CYCLE".ACTA METALLURGICA SINICA 51.10(2015):1273-1278.