Nano-indentation experiments on energetic crystals

Nano-indentation experiments are performed to investigate the mechanics responses of energetic crystals. Continuous stiffness method (CSM) based nano-indentation tests are employed to obtain the elastic moduli and hardnesses of β-HMX crystal (010) face and α-RDX crystal (210) face. The modulus and hardness can be induced from the load-displacement curves. The hardness value of the energetic crystals shows size effect. Microstructural fracture behaviors are analyzed using atomic force microscope (AFM) observations. The result shows that the cracks initiate and expand with the increase in load force. The direction of the crack is also the cleavage direction of the energetic crystal. The results presented here may be crucial in predicting the ignition mechanism of energetic crystals.