To evaluate the plastic zones of dynamic fracture, instrumented Charpy impact tests of high carbon bearing steels are conducted. The amount of plastic zone size left on the fracture surface is evaluated from the X-ray diffraction profiles. An analysis is presented of the relationship between the X-ray diffraction profiles and fracture mechanics parameters. The results are discussed in correlations between dynamic stress intensity factor and absorbed energy values. A good correlation exists between the plastic zone size and the dynamic stress intensity factor.
The fraction of retained austenite is determined from X-ray diffraction profiles at surfaces of fractures and also beneath the surfaces of fractures.
It shows the work hardening is introduced by the strain energy in the plastic zones. The values of the proportionality constant, α, determined for various kinds of dynamic fracture are related to half-value breadth by the function
where B0 and BF are average of half-value breadth which are given by core of material and plastic zone of dynamic fracture.