Effect of indentation depth and strain rate on mechanical properties of Sn0.3Ag0.7Cu

In this paper, nanoindentation tests with continuous stiffness measurement (CSM) technique were conducted on Sn0.3Ag0.7Cu (SAC0307) at room temperature. The mechanical properties and creep behavior of SAC0307 under different indentation depths and strain rate were studied. Results show that SAC0307 alloy has good plastic deformation ability and the contact stiffness increases linearly with the depth of the indentation. Under different indentation depths and strain rates, the hardness of the material will be affected by the indentation size effect (ISE). Moreover, the hardness shows a certain strain rate sensitivity under the action of different strain rates. The elastic modulus of the material is almost constant with the increase of the indentation depth during the indentation process. But at lower indentation depth (hmax = 500 nm), the elastic modulus-displacement curve fluctuates greatly due to ISE affect. Based on the Nix-Gao model, the hardness (H0) of SAC0307 is 0.2GPa, and the micro characteristic length h* is 867 nm. For the same holding time, creep deformation is more evident under high strain rate and indentation depths. The creep strain rate decrease with the increase of holding time and tends to a constant value.