High Pressure Synthesis And Characterization Of Several Copper-Containing Intermetallic Compounds

In the present work,a kind of quasicrystalline approximant phase Al₄Cu₉ phase as well as a modulated Cu₃Sn phase have been synthesized by high-pressure sintering method.Their crystal structures have been studied by single crystal X-ray diffraction technique combined with scanning electron microscopy.In addition,some copper-rich phases related to the Al₄Cu₉ and Cu₃Sn were analyzed from topological approach.Firstly,an Al₄Cu₉ bulk sample was synthesized by high-pressure sintering method.After selecting a suitable piece of single crystal particle in the precipitates,several diffraction data sets were collected by four-circle single crystal X-ray diffractometer.The crystal structure of Al₄Cu₉ was solved and refined by APEX3 software.The unit cell parameters of the crystal are in consistent with previous reported results except that there are Cu/Al atoms partially occupied positions.Topological analysis of the Al₄Cu₉ phase reveal that its unit cell contains two kinds of clusters.Secondly,Cu₃Sn bulk samples were prepared by high-pressure sintering method.Single crystal X-ray diffraction analysis indicated that the precipitate contains a long period modulation structure.Based on the observations,several Cu₃Sn phases with double period,four period and six period modulation structure have been proposed.Meanwhile,the mechanical stability,the thermodynamic stability and dynamic stability of the proposed double period phase have been investigated by using the first-principles calculations method.Finally,the crystal structure and mechanical properties of selected three groups of copper-rich phases related to Al₄Cu₉ and Cu₃Sn have been compared.It was found that when the crystal structures of these phases are identical,their shear modulus and bulk modulus are similar even their cell parameters are slightly different owing to different elements,implying they behave similar macroscopic plasticity or brittleness properties.