Effects of strain rates on dynamic deformation behavior of Cu-20Ag alloy

Copper alloy is widely used in high-speed railway, aerospace and other fields due to its excellent electrical conductivity and mechanical properties. High speed deformation and dynamic loading under impact load is a complex service condition, which widely exists in the field of national defense, military and industrial application. Therefore, the dynamic deformation behavior of the Cu-20Ag alloy was investigated by Split Hopkinson Pressure Bar (SHPB) with the strain rates of 1000-25000 s(-1), high-speed hydraulic servo material testing machine with the strain rates of 1-500 s(-1). The effect of strain rate on flow stress and adiabatic shear sensitivity was analyzed. The results show that the increase of strain rate will increase the flow stress and critical strain, that is to say, the increase of strain rate will reduce the adiabatic shear sensitivity of the Cu-20Ag alloy. The Cu-Ag interface has obvious orientation relationship with (111)(Cu)//(111)(Ag);((1) over bar 11)(Cu)//((1) over bar 11)(Ag); ((2) over bar 00)(Cu)//((2) over bar 00)(Ag) and [0 (1) over bar1](Cu)//[0 (1) over bar1](Ag) with the increase of strain rate. The increase of strain rate promotes the precipitation of Ag and increases the number of interfaces in the microstructure, which hinders the movement of dislocations and improves the stress and yield strength of the Cu-20Ag alloy. The concentration and distribution density of dislocations and the precipitation of Ag were the main reasons improve the flow stress and yield strength of the Cu-20Ag alloy. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

Copper alloy is widely used in high-speed railway, aerospace and other fields due to its excellent electrical conductivity and mechanical properties. Increase of strain rate can reduce the adiabatic shear sensitivity and promote the precipitation of Ag in Cu-20Ag alloy, which in turn improves the strength of the alloy.