Theoretical model for yield strength of monocrystalline Ni3Al by simultaneously considering size and strain rate
(1. State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China;
2. School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China;
3. School of Physics, Beihang University, Beijing 100191, China;
4. School of Civil and Mechanical Engineering, Curtin University, Perth, WA 6845, Australia)
2. School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China;
3. School of Physics, Beihang University, Beijing 100191, China;
4. School of Civil and Mechanical Engineering, Curtin University, Perth, WA 6845, Australia)
Abstract: To comprehensively describe the size and strain rate dependent yield strength of monocrystalline ductile materials, a theoretical model was established based on the dislocation nucleation mechanism. Taking Ni3Al as an example, the model firstly fits results of molecular dynamics simulations to extract material dependent parameters. Then, a theoretical surface of yield strength is constructed, which is finally verified by available experimental data. The model is further checked by available third part molecular dynamics and experimental data of monocrystalline copper and gold. It is shown that this model can successfully leap over the huge spatial and temporal scale gaps between molecular dynamics and experimental conditions to get the reliable mechanical properties of monocrystalline Ni3Al, copper and gold.
Key words: yield strength; size; strain rate; monocrystalline Ni3Al