Abstract
In a previous report of the present authors, it was shown that the cutting performance of medium carbon P30 alloy fell down by the addition of nitrogen (N). To describe the phenomenon, studies on the mechanical properties of the alloy with different grain sizes of βt (N) (WC-TiC-TiN-TaC solid solution) were undertaken, paying attention to the thermal stability at low temperature (973K).
It was noted that, when the N contained alloy was annealed at 973K, precipitation of Co3W became faster than that occurred in the usual alloy free from N, and resulted in the decrease in the mechanical properties. It was suggested that the cutting performance of N contained alloy was related to the thermal instability due to the fine structure of the βt(N) grains.
