{101^(-)2}twinning nucleation in magnesium assisted by alternative sweeping of partial dislocations via an intermediate precursor

摘要

Molecular dynamic simulation and transmission electron microscopy(TEM)characterization was employed to investigate the{1012}twinning mechanism in magnesium.A partial dislocation assisted twinning nucleation mechanism was proposed based on simulation results,in which the twin lattice was reconstructed from parental matrix by two-step sweeping of partial dislocations on different close packed planes from matrix and the subsequently formed twin precursor respectively.A{101^(-)2}twin precursor was observed adjacent to matrix/twin interface by a spherical aberration corrected TEM,which indicated the hexagonal-close-packed(hep)matrix-quasi face-centered cubic(fee)twinning precursorsh.c.p twin transformation sequence during{101^(-)2}twinning process.