Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7177350 | Journal of the Mechanics and Physics of Solids | 2018 | 58 Pages |
Abstract
In-situ ultra high speed optical imaging with 200â¯ns temporal resolution is used to gain insight into the evolution of twinning in single crystal magnesium under dynamic loading. Under compression along the a-axis, nucleation of twins is observed to occur on two conjugate {101¯2} twin planes. Twin nucleation appears to be stress-driven with the first twins nucleating at resolved stresses of 5-7â¯MPa. These first twins propagate across the specimen at very high speeds of the order 1âkm/s. After the first twins stop growing, twin boundary growth is observed to be very small and relatively slow. The nucleation of additional twins from the boundaries of pre-existing twins is found to be preferred over twin boundary growth at these rates of loading. As a result, twin nucleation is found to have a dominant contribution to twin volume fraction evolution at later times. Lastly, twinning is found to have a dominant contribution to the net plastic strain at these strain rates.
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Authors
Vignesh Kannan, Kavan Hazeli, K.T. Ramesh,