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Yield strength of the B1 and B2 phases of NaCl

1988; American Geophysical Union; Volume: 93; Issue: B4 Linguagem: Inglês

10.1029/jb093ib04p03270

2156-2202

Charles Meade, Raymond Jeanloz,

Nuclear Materials and Properties

We have measured the quasi‐static yield strength of NaCl to 41 GPa at room temperature. Between 0 and 28 GPa, the strength of the B1 phase increases eightfold, from 0.08 to 0.65 GPa. Across the B1‐B2 transition, the strength of NaCl decreases about 50%. We show that this result is consistent with the measurements of Bridgman [1937] on the shear strength of the B1 and B2 potassium halides to 5 GPa. We propose that the simultaneous increases in coordination and nearest‐neighbor distance have opposite effects on the change in shear strength across B1‐B2 transitions. Increasing the atomic coordination makes the B2 structure stronger than the B1 while increasing the nearest‐neighbor distance decreases the strength of the high pressure phase. In NaCl the large increase in nearest‐neighbor distance more than offsets the effect of increased coordination, and thus the B2 phase is weaker than the B1 phase.