Mechanical properties and microstructural evolution of the spray formed 2195 Al–Li alloy extruded sheet at warm temperatures

Abstract

The mechanical properties and microstructure evolution of the spray formed 2195 alloy extruded sheet at warm forming temperatures (100 °C–300 °C) were systematically investigated in this work. The results showed that the yield strength and ultimate tensile strength of the alloy declined obviously as the temperature rose, while the elongation increased initially and then decreased. With an increase in the strain rate, the yield strength and elongation of the alloy decreased, whereas the tensile strength increased. In addition, the tensile fracture behavior of the alloy was significantly affected by the temperature, and the fracture mode gradually shifted from intergranular fracture to ductile fracture as the temperature rose. The softening mechanism of the alloy was dominated by the dynamic recovery at different temperatures, and a certain degree of dynamic recrystallization was observed at 300 °C, which resulted in a dramatic decrease in the dislocation density of the alloy. Moreover, with an increase in temperature, coarser grains also appeared. Besides, the dislocation density and grain size of the alloy decreased initially and then increased with an increasing strain rate. Finally, it was found that the texture component of the alloy under different test conditions was mainly composed of deformation textures such as Brass and S. With the temperature increasing, the alloy showed a decrease first and then an increase in the texture strength, while the texture strength of the alloy increased continuously as the strain rate increased.