Explanation
A small amount of impurities or alloy elements are not uniformly distributed in the crystal, but preferentially distributed in the grain boundary layer. The tempering embrittlement of structural steel is caused by the segregation of P, Sh, As, Sn and other atoms at the segregation in grain boundary; The segregation in grain boundary of Sb, Bi, etc. in Cu and segregation in grain boundary of O2 in W are very easy to cause intergranular fracture. The enrichment of solute components caused by segregation in grain boundary creates conditions for precipitation of new phase at grain boundary.
Classification
Fundamental of Material Science -> Structural basis of materials