Role of Ultrafine Microstructures in Dynamic Fracture in Nanophase Silicon Nitride
نویسندگان
چکیده
Rajiv K. Kalia, Aiichiro Nakano, Andrey Omeltchenko, Kenji Tsuruta, and Priya Vashishta Concurrent Computing Laboratory for Materials Simulations, Department of Physics and Astronomy and Department of Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803 (Received 4 November 1996) Using 106-atom molecular-dynamics simulations, we investigate dynamic fracture in nanophase Si3N4. The simulations reveal that intercluster regions are amorphous, and they deflect cracks and give rise to local crack branching. As a result, the nanophase system is able to sustain an orderof-magnitude larger external strain than crystalline Si3N4. We also determine the morphology of fracture surfaces: For in-plane fracture surface profiles the roughness exponent z 0.57 and for outof-plane profiles the exponents z' 0.84 and zk 0.75 are in excellent agreement with experiments. [S0031-9007(97)02706-3]
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