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 of Al Cu Fe B polycrystalline quasicrystal is evaluated as 134GPa,and the fracture toughness is about 1.36 MPa·m-1/2.For the Vickers indenter,the cracking threshold is in the range of 250MN-500MN.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.