The Effect of Second-Phase Fraction on the Spall Properties of Ferrite-Pearlite Steels

Two ferrite-pearlite steels (1045 and A283) were subjected to spall recovery experiments to reveal the influence of pearlite fraction on spall strength and total damage. The A283 (20 % pearlite) alloy exhibited a higher Hugoniot elastic limit (HEL) and spall strength compared to 1045 (60 % pearlite). Post-mortem characterization of recovered samples revealed cementite lamellae cracking within the pearlite of 1045, suggesting that pearlite reduces spall strength by providing low-energy damage nucleation sites. The rate of damage growth and coalescence, as inferred from free surface velocity histories, was similar between the two alloys. However, 1045 exhibited more continuous cracks compared to a greater prevalence of discrete voids in A283. This work reveals the role of pearlite in the spall behavior of ferrite-pearlite steels, and further elucidates the influence of relatively brittle, second-phase particles on dynamic deformation.