应变时效对微合金钢显微组织结构的影响

Effect of Strain Ageing on Microstructures of Microalloyed Steels

研究了微合金钢应变时效处理前后的显微组织结构。结果表明,组织为铁素体和珠光体,铁素体呈板条形状。微合金元素的碳氮化物主要分布于晶内,少量分布于晶界上,晶内析出相尺寸远小于晶界析出相。析出物形状有圆形以及短棒形,尺寸由几纳米左右到几百纳米不等。时效后仅发现C原子在位错线附近偏聚,微合金元素在时效前对微量N元素绑定作用导致N原子未能参与Cottrell气团形成。

Microstructures of microalloyed steels before and after strain ageing treatment were investigated. It was found that the microstructure consisted of both lath ferrite and pearlite. Most of carbides and/or nitrides of microalloying elements distributed inside grains and a little distributed at grain boundaries. The precipitated phases inside grains were much smaller in size than those at the grain boundaries. The precipitates were either circular or short bar-like, with sizes from few nanometers to several hundred nanometers. After ageing only carbon atoms segregated around the dislocations and nitrogen did not participate in producing the Cottrell atmosphere because it was fixed by alloying elements before the ageing.