Spall strength dependence on peak stress and deformation history in Lean Duplex Stainless Steel 2101

The influence of peak compressive stress on the dyamic tensile fracture (spall) in a multi-phase steel, austenite, ferrite and martensite phases, was investigated in as-received and pre-strained conditions. Plate impact experiments were done at-3.0 GPa and-6.0 GPa compressive peak stresses. Results showed that peak stress increase results in about 20% increase in the spall strength for samples tested in the as-received condition, and about 15% increase for the pre-strained samples. These increases could be related to the effects of peak stress on the tensile stress that causes spallation. However, introducing plastic deformations in the pre-strained samples had negligible effects on the spall strength. Microstructural examinations revealed that incipient spall damage was parallel to the phase boundaries and mainly accommodated by ferrite grains as quasi-cleavage transgranular fracture. Samples shocked in the as-received condition with full spallation experienced a quasi-cleavage fracture within the ferrite compared with a cleavage fracture within the ferrite for samples shocked in the pre-strained condition. Deformation within the austenite phase due to plate-impact testing was dependent on the initial sample condition, the pre-strained samples showed more deformation than the as-received samples.

Automated summary

Increasing peak compressive stress leads to an increase in spall strength, which also affects tensile stress. Microstructural examinations reveal that spall damage is mainly accommodated by ferrite grains.