Effects of strain rate on flow stress of recycle simulant aluminum alloys based on A6082 aluminum alloy

Strain rate sensitivities of flow stress for two types of recycle-simulated aluminum alloys based on A6082 aluminum alloy were examined in strain rates ranging from 10‒3 to 10+3 s‒1. The recycle-simulated aluminum alloys included the amounts of Si, Fe and Cu beyond the standard range. The strain rate exerted no influence on the flow stress until it reached the strain rate of 10+3 s‒1; at this point, the flow stress exhibited a precipitous increase. The strain rate sensitivity index, m value, of type H and type I was negative until 10+3 s‒1, because the flow stress of type H and type I increased by the addition of Si, Fe and Cu. The strain rate sensitivity index over the strain rate of 10+3 s‒1 was independent of the addition of Si, Fe and Cu. The strain rate jump tests between strain rates of 10‒4 to 10‒3 s‒1 were also carried out to discuss strain rate sensitivity index, activation volumes and dislocation densities. From results of conductivity, the addition of Si, Fe and Cu brought to the increment of solid solution amount which is closely related to a reduction in activation volume and an increase in tensile strength.