Effect of short carbon fiber content on SCFs/AZ31 composite microstructure and mechanical properties

The magnesium matrix composites containing various content of short carbon fibers reinforcement (SCFs/AZ31) were fabricated by ball milling and solid state synthesis. Morphologies of composite, distribution of SCFs, and interface of matrix and reinforcement were analyzed. The effect of SCFs content on the mechanical properties of the composite was studied. When the content of SCFs is less than 3%, SCFs uniformly distribute in the composite and promote dynamic recrystallization, the refining effect of grain is obvious, and meanwhile SCFs can play the effect of load transfer to the matrix. With the increase of SCFs content, the degree of aggregation increases, the grain size of composite increases and mechanical properties decrease. For mechanical performance, the strengthen effects was firstly enhanced and then deteriorated with increasing SCFs content. The main strengthening mechanisms of composite are grain refinement strengthening, thermal residual stress strengthening, and load transfer strengthening.