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The shock-induced structural instability for three kinds of maraging steel is studied
with two experimental techniques: Taylor technique and uniaxial strain conditions. Spall
strength of steels is shown to be determined by the structural instability threshold under
compression at the front of compressive pulse. Microstructure investigation of post-shocked
specimens show that structural instability of maraging steel results from two factors: (i)
disintegration of strengthen phase created in the process of aging of steel and (ii) shock-induced
nucleation of localized austenite inclusions responsible for decrease of yield stress and
fragmentation. Dynamic fracture of maraging steels is found to occur along the boundaries
between shock-induced austenite laths and rest of the matrix.
Keywords: shock loading; structural instability; austenite; intermetallide; spallation. |
full paper (pdf, 1600 Kb)