Intergranular embrittlement of iron by phosphorus segregation: an atomistic simulation

The intergranular embrittlement in bcc iron by the grain boundary (GB) segregation of phosphorus is investigated using an atomistic simulation. The inhibition of the nucleation of dislocations near the crack tip is found to be the governing mechanism of the intergranular embrittlement in phosphorus-containing iron, in contrast to the conventional reasoning that focuses on the GB decohesion. The correlation between the nucleation of dislocations and dislocation transfer across a GB (GB strengthening) is discussed. Experimental evidence and supplementary simulation results that support the new finding in terms of the GB strengthening are also demonstrated. (paper)