杨京俊
,
柯伟
金属学报
本文研究了LD10铝合金和Ti-6Al-4V合金近门槛值疲劳裂纹扩展的断口形貌。SEM观察表明:两种合金的近门槛值区域(1×10~(-7)-1×10~(-5)mm/cycle)的微观断口形貌均为循环解理刻面;在LD10铝合金中循环解理刻面多数呈锯齿型或梯田状,而在Ti-6Al-4V合金中主要为孤岛状循环解理刻面。 本文在实验观察的基础上,进一步阐明了近门槛值疲劳裂纹扩展机理。
关键词:
疲劳裂纹
,
fractograph
,
near-threshold
ZHENG Yesha WANG Zhongguang AI Suhua State Key Laboratory of Fatigue and Fracture for Materials
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China
金属学报(英文版)
SEM microfractography of near-threshold fatigue crack propagation were carried out in the dual-phase steels of 3 martensite morphologies and 6 volume fractions of martensite (V_m). All of them are featured by cyclic cleavage characteristics in near-threshold region,i.e.,main- ly controlled by mode Ⅱ stress.In the higher ΔK regions,the fracture surfaces are character- ized by mixed modes including cyclic cleavage facets,two types of secondary cracks and striations,etc..The roughness-induced crack closure of fracture surface is attributed primarily to extreme high fatigue crack growth threshold values.
关键词:
dual-phase steel
,
null
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null
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null
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