Temperature dependence of the shock-induced reversal of martensite to austenite in an iron-nickel-carbon alloy

Shock-Induced Martensite Reversal in Fe/30%Ni

“…Loree et al(1966) reported that addition of Ni to Fe reduced the a -c phase transition pressure, and they gave a value of approximately 82 kbar for the transition when Ni concentration was 30%. Rohde (1970) later suggested that the Fe/Ni/C/Mn/Si-70.45/28.4/0.5/0.45/0.2% alloy had a transition pressure less than 10 kbar at 390 0 C. Fowler et al (1961) showed that an 18/8-Cr/Ni stainless steel had a transition pressure of 30 kbar at room temperature, but Gust and Royce (1970) in remeasuring a pire…”

“…This makes it possible to determine effects of transition on shear by varying specimen thickness and driving pressure, and to thus supplement variation of other physical parameters which alter relative amplitudes of HEL and transition. It has already been observed that this can be accomplished by variation of alloying materials (Blackburn et al, 1965;Stepakoff and Kaufmann, 1968;Fowler et al, 1961;Loree et al, 1966;Gust and Royce, 1970) in iron and by temperature variation (Rohde, 1970).…”

“…The first step toward this objective is based on the observations by Rohde (1970) that the amplitude of the elastic wave in shocked Fe/30%Ni is independent of temperature and that the pressure of the cx-y or a-e transition diminishes monotonically with temperatures apparently dropping below the elastic wave amplitude at 400 0 C. If transition pressure is less than elastic wave amplitude, the structure of the resulting shock wave is sensitive to collapse of the stress deviators. This can be seen with reference to Fig.…”

“…The upper points on the a-phase curve by Loree et al (1966) and by Rohde (1970) are transition states at which the a-y phase transformation occurs. The difference between them may result from small differences in composition of their materials.…”

“…a-phase, Graham et al (1967) 220-0 y-phase, Graham et al (1967) 0-a-phase, HEL, Rohde (1970) Transition state, Loree et al (1966) …”