In order to improve the accuracy and comparability of hardness and elastic modulus measurements in nanoin-dentation, an evaluation of the creep behavior and its influence on the mechanical properties of the electrode-posited nickel film has been conducted. The influence of loading time and hold period on the hardness and elastic modulus results at maximum load 5000 μN has also been examined. It is found that with increasing the loading time, the creep value is decreased. However, the creep value is increased when the hold period is increased. The elastic modulus results are more reliable if the hold period is longer. If the hold period is long enough, the loading time has no remarkable effect on the hardness and elastic modulus measured.
In this paper,mechanical properties of Nickel film under residual stress have been systematically examined by finite element method in nanoindentation.It was found that load-displacement curves shifted under elastic residual stress and residual stress exceeded the yield stress for fixed indentation depth.Indentation profiles changed monotonously with compressive and tensile stresses at peak force which determinates contact area observed directly by finite element modeling (FEM).The elastic residual stress has an effect slightly on the hardness but residual stress exceeded the yield stress shows a remarkable effect in nickel film.The hardness increased when residual stress exceeded the yield stress increased under tensile and compressive stress applied to specimen.The relationship between residual stress and hardness was linear.It was found that residual stresses didn't affect elastic modulus whether elastic residual stress or plastic stress was applied to specimen.
Lizeng Ling,Shiguo Long,Zengsheng Ma and Xu Liang Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education,and Faculty of Materials,Optoelectronics and Physics,Xiangtan University,Xiangtan 411105,China
