Find the answer of the given Problem

Problem-A biomedical engineer would like to fabricate a stainless steel rod as a intramedullary rod for fixing bone fracture.

Part 1- Would more or less energy be required to break the rod containing more defects and impurities, if all other parameters are comparable (dimensions, temperature, strain rate, etc.)?

Part 2- If the rod has a sufficient number of defects that an average person could bend it easily with hands, would one expect the bar to become more or less difficult to bend as the number of bending cycles increases? Why?

Part 3- To increase the fatigue strength, which method can be used without forming additional crystalline?

I need experts assist to find the energy be required to break the rod.