Microstructure and mechanical properties of Mg–Al–Mn–Ca alloy sheet produced by twin roll casting and sequential warm rolling

Microstructure and Mechanical Properties of Severely Deformed Mg-4.5Al-1.0Zn Alloy Processed by Asymmetric Rolling on Ingot and Twin Roll Cast Strip

“…Similar mean grain sizes are presented between both samples. While Wang et al, 13 studied the distribution of the grain size and reported the significant difference of the grain sizes: 11.2 μm for the ingot and grain size of 7.8 μm of the TRC. It is explained that particles located on grain boundaries would restrain the migration of grain boundaries, which is one of the main reasons for obtaining the homogeneous fine-grained microstructure.…”

“…Wang et al, 13 studied the ESR on TRC strip, and found that the microstructural evolution during warm rolling process is mainly characterized by deformation bands or shear bands, and no evident twins and DRXed grains are observed. Therefore, it is suggested that deformation mode for TRC sample is mainly dominated by dislocation multiplication mechanism.…”

“…The difference of the plastic deformation and different alloy could attribute to the different microstructures. The {10-12} tensile twinning or {10-11}-{10-12} double-twinning is most easily activated in Mg, and occur extensively at the early and later stage during compressive test or rolling at low and moderate temperature ranges for the Mg-Al-Zn system alloys 13 . The microstructures of the rolled sheets were examined using TEM, and a typical example is shown in Fig.…”

“…It could demonstrate that the TRC sample exhibits superior mechanical properties compared to ingot sample after warm rolling and subsequent annealing. The high strength of TRC sample is mainly due to the particle strengthening and solid solubility strengthening as well as fine-grain strengthening mechanisms resulting from the more and finer primary dispersed particles and smaller grain size, respectively 13 . However, the TRC sample shows slightly low elongation than that of the annealed ingot sample.…”

“…On the other hand, TRC Mg-4.5Al-1.0Zn is less sensitive to DRX, which are still present with large grains in the microstructure. Wang et al, 13 stated that the shear band-like fine grains Compared to those of the equal speed rolling (ESR) sheet of Mg-4.5Al-1.0Zn, the microstructures developed in the AR-processed sheet are more homogeneous and depict a higher percentage of DRXed grains. The occurrence of the DRX was attributed to high-dislocation density accumulation and high temperature rise of a deforming sheet due to large plastic deformation in AR compared with conventional rolling.…”