Structural evolution in annealing of mechanically alloyed AlCuFe icosahedral quasicrystal

To study the mechanism of AlCuFe quasicrystalline(QC) formation,the x-ray diffraction(XRD) and x-ray absorption fine structure(XAFS) were adopted.The combination of both the methods successfully overcame the difficulties in the analysis of the highly disordered structures.The results indicate that during the milling process,only Cu can incorporate into the lattice of Al to form an Al2Cu or Cu9Al4,which depends on the milling times.Fe remains the original structure of bcc α-Fe.However,annealing can drive the α-Fe to react with Al and Al-Cu compounds.The main products are Al7Cu2Fe compound or Al(Cu,Fe) solid solution,respectively.Then at higher temperature the Al7Cu2Fe transforms into the icosahedral Al65Cu20Fe15 quasicrystal.