Fig. 1. (a) Schematic of the DIC system and (b) experimental scene diagram consisting of (1) two synchronized cameras with standard f50-mm lens, (2) a collection trigger; (c) Specimen with random speckles. PC-1 is used to control the loading process, while PC-2 is used to capture deformed images and perform correlation calculations.

Fig. 2. Variation of engineering stress vs. engineering strain curves at various applied strain rates of 1.67 × 10-4-5.00 × 10-3 s-1 for 2.30 wt% Mg addition (a), 4.57 wt% Mg addition (b) and 6.91 wt% Mg addition (c). Magnified views of the data in sections A, B and C are shown as Fig. 2(d), (e) and (f), respectively. For clarity, all curves are separated vertically by a stress interval of 15 MPa.

Fig. 3. Propagative characteristics of bands, described by accumulated strain mapping, of these alloys at strain of 0.2 at 1.00 × 10-3 s-1. The reference images are the 1003 frame, the 1204 frame and the 1201 frame for alloys 1, 2 and 3, respectively. Sequence DIC method was used to obtain the band propagative characteristic.

Fig. 4. Schematic for calculating the PLC band width and the maximum PLC band strain.

Fig. 5. Variation of band width with Mg contents at 1.00 × 10-3 s-1. The band width is calculated from the equal-interval correlation results. Specimens of 5456 Al-based alloy are 1 mm-thick.

Fig. 6. Relationship between serration amplitude and maximum PLC band strain in the PLC band with various Mg contents.

Fig. 7. Variation of the amount of elastic shrinkage with Mg contents: (a) two selected serrations with amplitude of about 24 MPa and the corresponding DIC-calculated strain mappings; (b) the strain and displacement distributions in Y-axis of the center lines corresponding to serrations present in Fig. 7(a). The inset of (b) shows variation of the averaged strain outside PLC bands with Mg contents.