Cu-bearing HHCCI interface combined with first principles calculation and corrosive wear resistance

Abstract

The corrosive wear resistance of copper-bearing HHCCI was tested through experiments and HRTEM, combined with first-principles calculations to study the atomic structure, interface fracture work, thermodynamic stability, electronic structure and bonding structure of six Fe₃Cr₄C₃(01 $\bar{1}$ 0)/γ-Fe(101) interface models with different termination methods. The HRTEM results show that the interface formed by (01 $\bar{1}$ 0) of M₇C₃-type carbide and (101) of the austenite matrix is a coherent interface. The first principles calculation results show that the interface formed by the Fe₃Cr₄C₃(01 $\bar{1}$ 0)-Cr termination model and the γ-Fe (101)-2 termination model has the highest interface bonding strength. The Fe-end/7Fe-2 interface model is the most stable. Both the interfacial chemical energy and the interfacial elastic energy will affect the overall thermodynamic stability of the Fe₃Cr₄C₃(01 $\bar{1}$ 0)/γ-Fe (101) interface. The fracture work of Fe₃Cr₄C₃(01 $\bar{1}$ 0) and γ-Fe (101) is greater than the corresponding interface adhesion work. Moreover, the fracture work on each terminal end of M₇C₃ along the (01 $\bar{1}$ 0) surface is higher than that on each terminal end of γ-Fe along the (101) surface. The failure of HHCCI during corrosive wear may mainly occur in the interface area or the side close to the γ-Fe matrix. The chemical bonds in the Fe-end/7Fe interface are mainly Fe-Fe metal bonds, Fe-Cr metal bonds and some Fe-C polar covalent bonds. The chemical bonds in the Cr-end/7Fe interface are mainly Cr-Fe metal bonds and some Cr-C polar covalent bonds. The chemical bonds in the C-end/7Fe interface are mainly composed of Cr-Fe metal bonds, C-Fe polar covalent bonds and part of C-Cr polar covalent bonds, as a result, each interface exhibits different corrosive wear resistance potentials.