摘要
在应力比R=-1,转速为5000 r/min(83.3 Hz)和实验室静态空气介质环境下,研究了抗热腐蚀铸造镍基高温合金K435的旋转弯曲疲劳行为,得到其应力-疲劳寿命(S-Nf)曲线,测出其室温旋转弯曲疲劳极限为220 MPa.用扫描电镜观察了疲劳断口形貌,发现裂纹主要萌生在试样表面或近表面缺陷处,断口主要由裂纹萌生区、裂纹稳态扩展区和瞬间断裂区组成;并讨论了K435合金疲劳断裂的机制.用透射电镜观察了合金微观组织的变化.
Investigates the rotational bending fatigue behavior of Ni-based casting superalloy K435 at room temperature where the stress ratio of specimen equals - 1 and specimens are rotating at 5 000 r/min（83.3 Hz）. The stress-fatigue life curve relevant to rotational bending was obtained and the fatigue limit was measured to be 220 MPa. The fatigue fracture surface morphology was observed by SEM, and the fatigue cracks were found mainly initiated at the defects on specimen surface and/or near its sub-surface. The micrographics showed that the fracture is mainly due to the crack initiation, steady crack propagation and instantaneous fracture. Discusses the mechanism of the fatigue fracture of K435 superalloy and observes the change of its microstructure by TEM.
出处
《东北大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2007年第3期357-360,共4页
Journal of Northeastern University(Natural Science)
基金
国家自然科学基金资助项目(10477006)
