摘要
采用光学显微镜、扫描电镜、透射电镜并利用背散射电子衍射(EBSD)的方法对低碳NiCrMoV钢经不同冷却方式获得的马氏体/贝氏体组织、亚结构进行了定量分析,研究其对强韧性的影响。结果表明:10CrNi5MoV钢原始奥氏体晶粒内的组织经不同比例马氏体、贝氏体混合后,强度变化不大,而韧性随板条束和板条块尺寸的减小而提高,此时单个板条的宽度在0.38μm左右。进一步研究表明,板条束界和板条块界对裂纹扩展具有相同的阻碍作用,且板条块宽度对冲击韧性的影响作用远远大于板条束。因此,本研究中的板条块可作为低碳马氏体钢对韧性起作用的组织控制亚单元,即板条块尺寸为控制韧性的"有效晶粒尺寸"。
The martensite-bainite microstructure and substructure,which was obtained in a low carbon NiCrMoV steel under different cooling conditions,was quantitatively examined by means of optical microscope（OM）,scanning electron microscopy（SEM）,electron backscatter diffraction（EBSD） and transmission electron microscopy（TEM）.The effect of microstructure and substructure on strength and toughness of the steel was investigated.The results indicate that no significant change of strength is observed,however,toughness is enhanced remarkably with decreasing of the packet and block size in the lath martensite-bainite 10CrNi5MoV steel with the lath width of 0.38 μm.It is found that both the packet and block boundaries have the same hindering effect on crack extension,and the effect of the block width on impact energy is much larger than that of the packet.Therefore,the block is the controlling substructure for toughness in the steel,i.e.the block size is＂the effective grain size＂for controlling impact toughness.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2010年第10期63-69,共7页
Transactions of Materials and Heat Treatment
