| The dual phase?-TiAl/?2-Ti3Al based alloy has the advantages of high melting point,high elastic modulus,low density and good fracture toughness,and is one of the key research fields.However,the poor ductility and difficult processing limit TiAl alloys'applications.Therefore,it is of great theoretical significance and practical value to improve its ductility.The first-principles method based on the density functional theory method,Material Studio6.0 software and high-performance computing platform are used in this research work.The doping effects of Ru,Mn or Re on?-TiAl/?2-Ti3Al interface systems are studied and discussed from several aspects including geometric properties,energy properties,fracture works and electronic properties.The results show that the Ru,Mn and Re doping dual-phase?-TiAl/?2-Ti3Al interface systems have changed their geometrical properties,and their densities slightly increase,but are still retaining the advantages of low density and light weight.The average formation energy of each system is negative,and they are predicted to exist stably.The stabilities of system Ru?or Mn,Re?-Sa5,Ru?or Mn,Re?-Sb1,Ru?or Mn,Re?-Pa55 and Ru?or Mn,Re?-Pb1decrease,which are beneficial to the improvement of ductility.But the stabilities of system Ru?or Mn,Re?-Sa2,Ru?or Mn,Re?-Sb2,Ru?or Mn,Re?-Pa33 and Ru?or Mn,Re?-Pb3 increase,which are harmful to the improvement of ductility.The calculation results of fracture work show that the fracture strengths of system Mn-Sa5,Ru?or Mn?-Sb1,Ru?or Mn?-Pa5,Ru-Pb1decrease,which is important to promote their ductility.The electronic densities of state at the Fermi level,overlapping populations and Mulliken populations of system Ru-Pa5,Ru-Pb11 and Mn-Pa55 are calculated and analyzed.The results show that the internal cause of the improvement of ductility is the decrease of hybridization between Ti-d orbital electron and Al-p orbital electron,and the decrease of anisotropy of covalent bond strength in the systems. |
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