High-Rate Mechanical Properties of JA2 Propellant at Temperatures from -50 to 80 deg C

JA2, a viscoelastic polymeric propellant, was studied with uniaxial compression to approximately 70% engineering strain at a strain rate of approximately 100 s-1 at each decade of temperature from -50 to 80 deg C. Each sample after postcompression relaxation was cold-cleaved for postmortem examination. The stress/strain curves and postmortem examination showed the trend of reduced ductility as the temperature decreased. The stress/strain curves of all temperatures showed that a strain of approximately 35% would allow the sample to deform without achieving the point of failure. Compression experiments at selected temperatures were repeated with a limit of this strain. Postmortem examination of the cold-cleaved grains was performed using scanning electron microscopy, the results of which showed the transitions from viscous flow to void and tear formation to crack tip propagation prior to structural failure of the sample. The original document contains color images.