摘要
为了探索汽车行业广泛应用的DP780双相钢疲劳特性,通过在紧凑拉伸试样上加载等幅值载荷进行试验,研究单一拉伸过载时DP780双相钢疲劳裂纹扩展行为。结果表明,随着过载比和过载引起的裂纹长度的增加,裂纹延迟周期数和疲劳寿命都呈现增加的趋势。在施加过载的过程中,在裂纹尖端前方形成了以解理面、撕裂岭、韧窝和孔洞为特征的月牙形的损伤区域。由于裂纹侧翼的过早接触,导致过载恢复后裂纹前沿的断口形貌受损严重。过载下的裂纹分叉对裂纹扩展迟滞效应没有显著的影响。在过载影响区和过载后稳定期均发生裂纹分叉,但分叉并没有延伸到材料内部。
In order to explore fatigue characteristic of DP780 dual phase steel widely used in the automobile industry,an experiment with the constant amplitude load on the compact tensile specimen were carried out. The fatigue crack growth behavior of DP780 dual phase steel subjected to single tensile overload was studied. The results shows that the increase of the overload ratio and the crack length caused by overload increases the number of delayed cycles and fatigue life.During the process of overload,a crescent moon shaped damage zone was formed at the front of the crack tip,which is characterized by cleavage surfaces,tearing ridges,dimples and voids. Due to the premature contact of the crack flank,the fracture morphology of the crack front is seriously damaged. The crack branching has no significant effect on the crack growth retardation under overload. The crack branching occurs in the overload affected zone and in the stable period after overload. However,the branching does not extend to the interior of the material.
作者
李松汾
LI Song-fen(Department of Mechanical Engineering,Baotou Iron and Steel Vocational Technical College,Baotou 014010,Nei Mongol,China)
出处
《钢铁》
CAS
CSCD
北大核心
2019年第3期82-86,共5页
Iron and Steel
关键词
双相钢
疲劳裂纹扩展
过载比
疲劳断口
dual phase steel
fatigue crack growth
overload ratio
fatigue fracture
