High Temperature Deformation of Cu-24 wt.%Ag Microcompostites
권희준Hoi Joon Kwon,홍순익Sung Ig Hong
Abstract
High temperature deformation of heavily drawn Cu-24 wt.%Ag filamentary microcomposite wires have been investigated. The filamentary microstructure tends to break up at high temperatures by spheroidization, grooving and/or recrystallization because of its high interface energy and high cold-work energy. Above 400℃, extensive recrystallization occurred and the grains with 300-500 ㎚ in size were observed in Cu matrix. As the deformation proceeds, the elongated silver lamellae and/or the region with numerous filaments break up and rearrange into chevron patterns which mostly lie perpendicular to the loading axis. The elongation up to 1000% was obtained at 500℃ at the strain rates of 7×10^(-4)/sec ∼ 3×10^(-3)/sec and the elongation up to 600% was obtained at 400℃ at the strain rate of 1×10^(-4)/sec. Arrays of dislocations in the matrix and near grain and phase boundaries were observed after superplastic deformation, supporting the slip-accommodated grain and/or phase boundary sliding.