Evaluation of Fracture Toughness of Al-Cu-Fe-B Quasicrystal

摘要

Vickers indentation test, a simple method for the toughness determination, is used to test the fracture toughness of Al_(59)Cu_(25.5)Fe_(12.5)B_3 polycrystalline quasicrystal . According to the profiles of the indentation, the radial crack size and related equation, the microhardness Hv, Young's modulus E, cracking threshold, and fracture toughness have been evaluated. The results show that the Young's modulus Al-Cu-Fe-B polycrystalline quasicrystal is evaluated as 134 GPa, and the fracture toughness is about 1.36 MPa centre dot m - 1/2. For the Vickers indenter, the cracking threshold is in the range of 250 MN - 500 MN. Moreover, the surface morphology of the indentations and the cracks are observed by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The relationship between the microstructure of quasicrystal and crack initiation and propagation is discussed in detail.