【摘要】 该文用USF-2000超声疲劳实验机研究了50CrV4高强度弹簧钢的超高周疲劳性能,并用Quan-ta600扫描电子显微镜对疲劳断口形貌进行了观察。研究结果表明,所有的疲劳裂纹都是从内部或亚表面的夹杂物处萌生,能谱分析表明夹杂物的成分主要是钙铝的氧化物,并且测量的夹杂物的尺寸超过了临界夹杂的尺寸,因此在疲劳断口上并没有观察到夹杂物周围的光学暗区(ODA)。在109的循环周次内,50CrV4钢存在疲劳极限,其S-N曲线的形式为传统的疲劳极限型。更多还原

【Abstract】 This paper investigates very high cycle fatigue(VHCF) properties of high strength spring steel-50CrV4 with USF-2000 ultrasonic fatigue testing,and then fatigue fractographs are observed by Quanta600 scanning electron microscope(SEM).Results show that fatigue cracks are all initiated from internal and subsurface inclusions,and the composition of inclusions are mainly oxides of calcium and aluminium,which is analyzed by energy dispersive X-ray spectrometer(EDXS).The size of inclusions measured are all larger than the size of critical inclusion,so in this experiment we don’t observe ODA around inclusion on the fatigue fracture surfaces.Fatigue limit exists in 109 cycles regime,and S-N curve is a traditional fatigue limit model.更多还原