STRAIN-INDUCED MARTENSITIC TRANSFORMATION IN 304L AUSTENITIC STAINLESS STEEL UNDER ECAP DEFORMATION

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	STRAIN-INDUCED MARTENSITIC TRANSFORMATION IN 304L AUSTENITIC STAINLESS STEEL UNDER ECAP DEFORMATION
	Yang Gang 1; Huang Chongxiang 2; Wu Shiding 2; Zhang Zhefeng 2
刊名	ACTA METALLURGICA SINICA
	2009-08-11
卷号	45 期号:8 页码:906-911
关键词	austenitic stainless steel equal channel angular pressing submicron grain martensitic transformation microscopic mechanism
ISSN号	0412-1961
通讯作者	Huang Chongxiang(chxhuang@imr.ac.cn)
英文摘要	The strain-induced martensitic transformation (SIMT) is considered to be an effective route to enhance the mechanical properties of metastable austenitic steels. Recently., it was found that the SMIT was favourable for the formation of nanocrystalline microstructures in some austenitic steels and titanium alloys, by using the technique of severe plastic deformation (SPD) for grain refinement. It is well known that austenitic stainless steel is sensitive to martensite transformation under plastic deformation at low temperature. However, the mechanisms of SIMT in austenitic stainless steel (AISI 304 series) under SPD, particularly the transformation mechanisms in small grains with sizes of submicronmeter and nanometer, are still lack of investigation. Equal channel angular pressing (ECAP) is one of the popular methods of SPD, which can produce bulk nanostructured metallic materials without any reduction in the cross-sectional area of specimen. It has been clarified that the shear deformation imposed by ECAP was the most effective route to trigger SIMT in austenitic stainless steel in comparison with uniaxial tension and compression. In this paper, the SIMT in 304L austenitic stainless steel was investigated under ECAP deformation at room temperature, in order to reveal the mechanisms of nucleation, growth and crystallography of strain-induced martensite. The microstructures of strain-induced martensite during ECAP deformation were carefully examined by X-ray diffraction and transmission electron microscope (TEM). It was found that in the case of coarse austenitic grains, the strain-induced marteniste nucleated at the intersection of deformation bands (including the bundles of stacking faults, deformation twins and platelets of epsilon phase) and kept the K-S (Kurdjumov-Sachs) but not the Nishiyama-Wassermann orientation relationships with austenitic grains. While in the case of small austenitic grains with sizes of several hundred nanometers, the strain-induced martensite preferred to nucleate at grain boundaries and grew up via swallowing the matrix of austenite. The martensitic grains followed the K-S crystallographic relationships with austenite too. Furthermore, the new nanocrystalline martensitic grains were easily rotated against each other by shear deformation, which prevented the coalescence of martensitic grains and was beneficial for the formation of nanocrystalline structures. According to the K-S orientation relationship, the {110} planes of martensite are converted from the {111} planes of austenite, keeping the < 1 (1) over bar0 > direction of martensite parallel to the <(1) over bar 11 > direction of austenite as well. The difference and mechanism of SIMT occurring in coarse austenitic grains and submicron austenitic grains were discussed in detail.
资助项目	National Natural Science Foundation of China[50701047]
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000269601400002
资助机构	National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/98075]
专题	金属研究所_中国科学院金属研究所
通讯作者	Huang Chongxiang
作者单位	1.Cent Iron & Steel Res Inst, Beijing 100081, Peoples R China 2.Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Yang Gang,Huang Chongxiang,Wu Shiding,et al. STRAIN-INDUCED MARTENSITIC TRANSFORMATION IN 304L AUSTENITIC STAINLESS STEEL UNDER ECAP DEFORMATION[J]. ACTA METALLURGICA SINICA,2009,45(8):906-911.
APA	Yang Gang,Huang Chongxiang,Wu Shiding,&Zhang Zhefeng.(2009).STRAIN-INDUCED MARTENSITIC TRANSFORMATION IN 304L AUSTENITIC STAINLESS STEEL UNDER ECAP DEFORMATION.ACTA METALLURGICA SINICA,45(8),906-911.
MLA	Yang Gang,et al."STRAIN-INDUCED MARTENSITIC TRANSFORMATION IN 304L AUSTENITIC STAINLESS STEEL UNDER ECAP DEFORMATION".ACTA METALLURGICA SINICA 45.8(2009):906-911.