Atomic-scale investigation of aging precipitation behaviors in pre-deformed Mg-Nd alloy
The precipitation behavior of the pre-deformed Mg-2.0％ Nd(mass fraction)binary alloy isothermally aged at 250℃ for 2 h has been systematically investigated by means of aberration-corrected high angle annular dark field-scanning transmission electron microscopy(HAADF-STEM).It is determined that the dislocations generated by pre-deformation facilitate the nucleation of secondary phases,leading to the formation of high density metastable precipitates which are different from the traditional uniform distribution along the{10(1)0}α habit planes.Atomic-scale observation shows that the precipitate-chains within the matrix consist mainly of the βS′and β1 phases.In addition,the precipitate-chains contain small amounts of β″ and βH′phases,as well as the βL′phase.These lamellar or lenticular βS′and β1 phases are fully coherent with the α-Mg matrix,with a{10(1)0}α habit planes,but are non-uniformly distributed along-the three directions of[11(2)0]α,[1(2)10]α and[(2)110]α.These results are expected to provide theoretical guidance for controlling the precipitation behavior of alloys via deformation to enhance the mechanical properties.
万方数据
维普
