铁素体晶粒尺寸及晶界夹杂物对球墨铸铁冲击断裂行为的影响  

The Effect of Grain Size and Grain Boundary Inclusion on Impact Fracture Behavior of Ferritic Ductile Iron

作　　者：蒋立鹏[1] 曲迎东[1] 张新宁[1] 李荣德[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,辽宁沈阳110870

出　　处：《铸造》2016年第8期774-778,共5页Foundry

基　　金：国家自然科学基金(51274142);辽宁省自然科学基金(2014028015)

摘　　要：在低温下对不同晶粒尺寸的QT400-18L及QT350-22L球墨铸铁件进行Charpy缺口系列冲击实验。实验结果表明,晶粒大小及晶界分布对冲击性能有明显影响;粗大晶粒QT400-18L铁素体球墨铸铁的解理断裂单元尺寸比细小晶粒的解理断裂单元尺寸大,低温冲击作用下解理裂纹开始和扩展遇到粗大晶粒的概率也相应较高。晶界处夹杂物的存在导致韧窝断口处往往存在一些细微孔洞,这些孔洞排布紧密且全部分布在变形的最后区域即韧窝的边缘部位,这种由夹杂物引起的显微孔洞的连接导致了材料的最终断裂。The impact toughness ofQT400-18L and QT350-22L ductile irons was measured by V-notch Charpy impact test at room and low temperatures. OM and SEM were used to analyze the size of ferritic grains and the cleavage facts. Experimental results show that the effect of grain size and grain boundary inclusion on impact toughness of ferritic ductile iron is obvious, and fracture facet size of coarse grain of 400-18L is bigger than fine grain. The probability of crack beginning, extending and meeting coarse grain will increase, the micro pores will be found at dimple fracture because of inclusion at grain boundary, these micro pores arrange at dimple edge tightly. Inclusions on grain boundaries lead to the formation of micro pores on dimple fracture, these micro pores lead to material rupture.

关 键 词：晶粒尺寸 晶界 球墨铸铁 冲击吸收功 

分 类 号：TG143.5[一般工业技术—材料科学与工程]