热模钢中碳化物动态析出与高温塑性的定量研究

研究了碳化物在热变形过程中的动态析出量与钢的高温塑性、晶内强度的定量关系。结果表明：晶内强度随碳化物动态析出量的增加而上升，高温塑性随之而降低．其脆化机制是晶内强度的上升加剧了晶界的热变形，从而导致显微裂纹在晶界上形核长大，最终呈现低塑性沿晶断裂。

A Quantitative Study of the Relationship between Dynamic Precipitation of Carbide and High-TemperatureDuctility of Hot Work Tool Steel

The relationship between high-temperature ductility,intragranular strength and dynam-ic precipitation of carbide of hot work tool steel during thermal deformation is investigated.It has been found that a large quantity of carbide is precipitated and the amount of dynamicprecipitation increases with the time. The high-temperature ductility deteriorates and intra-granular strength increases with an increases of dynamic precipitation of carbide. The mecha-nism of brittleness consists in an aggravation of the deformation of the grain boundary due toan increase of the intragranular strength,leading to the nucleation and growth of microcracks at the grain boundary and eventually the fracture with the grain boundary due to lowductility.