【摘要】 基于粘聚力模型和代表体积单元,采用原位显微观察和扩展有限元模拟,分析了石墨团聚对铁素体球墨铸铁单轴拉伸下的微区应力分布和裂纹演变机理的影响。结果表明,当石墨间距与直径的比值(l/d)高于1.8时,石墨与铁素体基体中裂纹萌生关联较小。随着团聚程度增大(l/d≤1.8),石墨与基体脱粘,裂纹易萌生在团聚石墨间的铁素体内,并沿垂直于拉应力方向扩展。团聚的石墨数量越多,团聚区域越容易产生裂纹。更多还原

【Abstract】 Based on cohesive force model and representative volume element,the effects of graphite agglomeration on microdomain strain distribution and crack evolution mechanism of ferrite ductile cast iron during the uniaxial stretching process were studied by means of insitu microscopic observation and extended finite element simulation.The results show that when the specific value( l/d,the ratio of the distance to diameter of graphite) is higher than 1.8,the graphite has little correlation with crack initiation in ferritic matrix.With the increasing of the degree of graphite aggregation( l/d≤1.8),the graphite is prone to debond with the matrix,the cracks are easily formed in the ferrite which among the graphite,and will extend in the direction vertical to the tensile stress.The more agglomerated graphite,the crack initiates more easily in the agglomeration field.更多还原