YIELD POINT PHENOMENA IN MAGNESIUM-LITHIUM SINGLE CRYSTALS
An investigation was conducted on the deformation of single crystals of alpha solid solution (12.5 at.% Li in Mg) specially oriented for basal slip. Crystals were tested in tension over the range of temperatures between 77 and 845 deg K. The alloy has a critical resolved shear-stress at least 10 times that of pure Mg. Whereas the critical resolved shear-stress was temperature-dependent below 250 deg K, it was relatively constant over the higher temperature range. Above 400 deg K all crystals fractured on the prismatic planes following duplex prismatic slip. Twinning, kinking, and accommodation bending was observed in areas adjacent to subgrain boundaries, and the shear-stress vs shear-strain curves for the crystals were correlated with the various types of deformation markings observed on the surfaces of the strain specimens. The thermally activated deformation mechanism below 250 deg K probably arises from the dislocation intersection process whereas the higher temperature athermal behavior is thought to be a result of short-range ordering. (auth)
- Research Organization:
- Univ. of California, Berkeley
- NSA Number:
- NSA-17-036307
- OSTI ID:
- 4639555
- Journal Information:
- Am. Soc. Metals, Trans. Quart., Journal Name: Am. Soc. Metals, Trans. Quart. Vol. Vol: 55
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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