The effect of deformation temperature on microstructure and superplastic flow in Al-Cu-Mg/Si(3)N(4)p composites

The effect of deformation temperature on microstructure and superplastic fl ow in Al-Cu-Mg alloy composite reinforced with Si3N4 particles (Si(3)N(4)p) , was investigated. The composites tensile-tested at 758, 773 and 788 K, ex hibiting high-strain-rate superplasticity, show high resistance to gain gro wth during the tensile deformation. However, the composite tensile-tested a t 798 K, exhibiting much lower elongation than the composites tensile-teste d at lower temperatures, shows considerable grain growth during the tensile deformation. The EDS analysis shows that concentration of the additive ele ments occurs at the interfaces and the analytical values depend on the samp ling points. The largest elongation is obtained at 788 K, which is close to the onset temperature for partial melting determined by DTA. On the other hand, the elongation significantly decreases at 818 K, which is close to th e end temperature for partial melting.