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