Precipitation of κ-Carbide in a V-Containing Austenite-Based Lightweight Steel

The precipitation behavior of kappa-carbides in a Fe-20Mn-9Al-1.2C-1.0V austenite based lightweight steel has been studied. V element is kept in solid solution by near-rapid solidification and precipitated as V-carbides by annealing, respectively. Aging treatments at temperatures of 500 degrees C to 600 degrees C were performed for the as-cast and cold-rolled steels. The results show that when the aging temperature is higher than 550 degrees C, intergranular kappa-carbides begin to appear along the austenite boundaries, and coarse kappa-carbides greatly reduce the ductility of the alloy. Cold rolling before aging precipitation can promote the precipitation of kappa-carbides and accelerate the eutectoid transformation of austenite. V element is slightly enriched in the region of kappa-carbides. First principles analysis shows that V segregation into kappa-carbides will increase the nucleation barrier energy. After annealing, precipitated V-carbides induce the subsequent precipitation of kappa-carbides in the form of band distribution, which is very different from the uniform precipitation without V-carbides.

Automated summary

The precipitation behavior of kappa-carbides in a Fe-20Mn-9Al-1.2C-1.0V austenite based lightweight steel has been studied. Cold rolling before aging precipitation can promote the precipitation of kappa-carbides and accelerate the eutectoid transformation of austenite. V element is slightly enriched in the region of kappa-carbides and affects the nucleation barrier energy. After annealing, precipitated V-carbides induce the subsequent precipitation of kappa-carbides in the form of band distribution.