Hot deformation and processing map of in-situ graphene reinforced magnesium matrix nanocomposites

It is necessary to have a deep understanding of the deformation behavior of magnesium matrix nanocomposites to achieve precise control of components. In this work, the as-cast graphene reinforced magnesium matrix nanocomposites were produced by in-situ vapor-liquid reaction. The flow stress features of the nanocomposites were studied by isothermal compression. The constitutive equation and the processing map of nanocomposites were established under the given load conditions based on the stress-strain curve. The sample is in a stable processing state at a compression temperature of 350 ℃∼450 ℃ with a compression rate of 0.001 s−1 and a compression temperature of 350 ℃ with a compression rate of 0.01 s−1. Furthermore, graphene distributed within the grains facilitated the retention of high dislocation density, which increased the driving force of recrystallization. Recrystallized grains can be generated by the progressive rotation of subgrain due to grain boundary migration being inhibited by graphene. This work provides an important guideline for the optimization of deformation techniques of in-situ nanocomposites. •Graphene achieves homogeneous dispersion and strong interfacial bonding simultaneously.•The constitutive equation and the processing map of nanocomposites were established.•The deformation mechanism of the hot compression process was studied.