Abstract
It is shown that tensile pulses generated by the reflection of compressive shock waves at a free surface can produce (γ+α′) martensitic transformation in an Fe-32.3 wt pct Ni-.035 wt pct C alloy. The tensile hydrostatic component of the stress interacts with the dilatational strains (0.04) produced by the martensitic transformation resulting in an increase of M s , the martensitic start temperature. The shock waves were produced by normal impact of a target by a projectile accelerated in a one-stage gas gun. Experiments were conducted at temperatures between −10° and −50°C (M s = −61°C) at a constant pressure of 1.5 GPa and pulse duration of 0.75 μs; and at variable pulse durations (0.19 – 1.5 μs) at a constant pressure of 1.5 GPa and a temperature of −30°C. Shock-induced inhomogeneities were observed in the recovered specimens. They manifested themselves as long bands with no crystallographic relationship to the structure and provided preferential nucleation regions for martensite. The observed inhomogeneous “stringers” serve as markers for the shock-induced inhomogeneities.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
