摘要
X射线衍射分析表明,在疲劳极限载荷下循环加载10^7次事,退火态16Mn在厚度约3个铁素体晶粒大小的表层内,300M钢在厚度经15个原奥氏体晶粒大小的表层内,喷丸强化300M钢在距表面200-320μm的亚表层内发生XRD效应的明显变化。
Evident changes in X-ray diffraction patterns are observed in surface or sub-surface layers of 16Mn and 300M steel specimens which have been tested under cyclic stress with stress levels equal to fatigue limits of correspondent steels and did not broken until 107cycles. Such layers are located at the surface for surface-unhardened 16Mn and 300M specimens and their thickness are about 3 diameters of ferrite grain and 15 diameters of original austenite grain, respectively; but for shot peened 300M specimen, such layer is located beneath the hardened surface layer, in the region with tensile residual stress, and its thickness is about 12 diameters of original austenite grain. These facts show that, even under the critical conditions for fatigue crack initiation, there always exist meso-scopical pre-yielding regions which consist of rather many grains and sustain back and forth sliding during fatigue test.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
1997年第2期191-194,共4页
Chinese Journal of Materials Research
基金
国家自然科学基金!59375915
关键词
疲劳裂纹萌生
细观过程
fatigue crack initiation meso-scopical process