Direction Dependence of Compressive Properties of Mg Processed by Directional Solidification

Abstract

Pure Mg consisting of elongated grains was fabricated by the directional solidification process, and its compressive properties were investigated at room temperature, 473 and 773 K under the conditions where the angle between the long axis direction of the elongated grains and the compression direction was 0, 45 and 90 degree. At room temperature, the specimen at the angle of 45 degree was fractured prior to " ¼ 0:3, although the specimens at the angles of 0 and 90 degree were not fractured even at " ¼ 0:3. In addition, the yield stress at the angle of 45 degree was higher than those at the angles of 0 and 90 degree. The (0002) basal planes were distributed at a tilt of 30-50 degree to the solidification direction. This was responsible for the higher yield stress at the angle of 45 degree. Also, the yield stress at the angle of 0 degree was lower than that at the angle of 90 degree. The lower yield stress at the angle of 0 degree was attributed to twinning. At 473 K, the yield stress at the angle of 45 degree decreased significantly. The large decrease in yield stress at the angle of 45 degree resulted from grain boundary sliding. At 773 K, the yield stresses were almost the same, irrespectively of the loading direction. Thus, compressive properties of the directionally solidified Mg were affected by the loading direction.

Improved mechanical properties of AZ31 magnesium alloy sheets by repeated cold rolling and annealing using a small pass reduction

“…After repeated cold rolling and annealing, the rolled samples in annealed condition still exhibit typical basal textures but the c-axis of some grains are tilted away from the ND towards the RD and lay on the ND-RD plane, which leads to the ellipsoidal distributions of basal texture intensity in the (0002) pole figures, as shown in Fig. 5b and c. This is mainly due to fact that the combination of non-basal slip and twinning results in the formation of such textures [31]. Compared with the basal texture intensity of the as-received sample, those of the repeated cold rolled samples in annealed condition gradually reduce with the increasing total rolling reduction, which is ascribed to the increasingly accumulated strain during repeated cold rolling.…”

Deformation twinning in nanocrystalline materials

“…In coarse-grained hcp metals and alloys, twinning is a common deformation mechanism because their small number of slip systems [56,[159][160][161][162][163][164][165][166][167][168][169][170]. In comparison, nc materials have a very different behavior in the formation of stacking faults and deformation twins.…”

“…Furthermore, the mechanisms for the formation of deformation twins are not very well studied even for coarse-grained bcc and hcp metals and alloys. Although the twinning mechanisms for coarse-grained and nc hcp metals are already under investigation [159][160][161]163,166,170,241,273,277,[328][329][330][331][332][333], it is not clear if the twinning phenomena and mechanisms observed in nc fcc metals also occur in nc bcc and fcc systems. For example, it is unknown if the grain size effect on deformation twinning observed in nc fcc metals also exists in nc bcc and hcp metals.…”

Effect of Micro-Alloying Elements on Deformation Behavior in Mg–Y Binary Alloys

“…2729) These texture changes during compression tests have been confirmed in magnesium and its alloys. 30,31) Thus, the addition of Y atoms does not bring about dramatic differences at the beginning of deformation.…”