【作者】 庞建超； 张孟枭； 李守新； 张哲峰；

【Author】 Pang Jianchao;Zhang Mengxiao;Li Shouxi;Zhang Zhefeng;Shenyang National Laboratory for Materials Science,Institute of metal research,Chinese Academy of Sciences;

【机构】 中国科学院金属研究所沈阳材料科学国家(联合)实验室；

【摘要】 为了深入分析控制疲劳强度关系的损伤机制,选择单相奥氏体不锈钢为研究对象,采用不同轧制工艺制备四种不同晶粒尺寸(粗晶、细晶、超细晶和纳米晶),分别进行拉伸和高周疲劳实验,系统分析晶粒尺寸及疲劳前后微观组织演变,分析疲劳试样表面形貌与断口特征。研究结果表明:随着晶粒尺寸下降,抗拉强度提高,疲劳强度先增加后降低;当超细晶材料的抗拉强度达到1170MPa时,疲劳强度最佳:随抗拉强度的提高,疲劳开裂位置由表面滑移带过渡到表面剪切带,甚至到内部夹杂物。最后试图揭示疲劳强度与抗拉强度关系及其疲劳断裂机制,为疲劳强度预测或材料优化设计提供实验证据与理论指导。更多还原

【Abstract】 To further analyze the mechanism determining the relationship between fatigue strength and tensile strength,austenitic stainless steels with different grain sizes were processed by different rolling technologies to carry out tensile and high-cycle fatigue experiments.Then,the grain size,microstructures evolution,sample surface and fracture surface morphologies of the steels were observed and analyzed before and after the fatigue tests.The experimental results demonstrate that with decreasing the grain size,tensile strength gradually increases,the fatigue strength increases firstly and then decreases;the ultrafine-grained steel with the tensile strength of1170 MPa can gain the optimum fatigue strength;however,with further increasing the tensile strength,fatigue crack initiation sites were gradually transferred from surface slip bands to shear bands,even to the interior inclusions.Finally,the relationship between fatigue strength and tensile strength and their intrinsic fatigue and fracture mechanisms were proposed to provide experimental verification and theoretical direction for predicting fatigue strength and designing materials.更多还原