leometwu的部落格

A chip that broke off from a thread rolling tooling  made of D2 tool steel.

The thin white layer on the top is highly stressed layer. Beneath is a light brwon layer which might have been slightly over-tempered by the heat generated during thread rolling.
 

Below: Note the gradual change of direction of primary carbide particles due to plastic flow of matrix material.
 
 
 

Above: interface between carbide and matrix is torn apart. Below: primary carbide cracked during thread rolling.
 

Carbide particles lying flat to the surface. They gave in to the plastic flow of the material and gradually change their orientation.