Dezhi Wang

Toughening of MoSi2 doped by La2O3 particles

Abstract Molybdenum disilicide (MoSi 2 ) with or without La 2 O 3 particles were synthesized by mechanical alloying (MA) and HP techniques. The fracture toughness at room temperature was measured by Anstis’ mode and the responded microstructures were analyzed by using SEM and X-ray. The results show that the addition of La 2 O 3 could obviously toughen the matrix. When the content of La 2 O 3 in MoSi 2 is about 0.9%, the fracture toughness value increases by about 50% more than that of pure MoSi 2 . We think, the corresponding toughening mechanisms depend on the following: fine-grain, microcracking, crack deflection, crack microbridging, crack bowing and branching.

Fabrication of Al-Cu laminated composites by diffusion rolling procedure

Abstract A diffusion rolling procedure was employed for the fabrication of Al–Cu laminated composites; the microstructure and mechanical properties of the interface were investigated. With diffusion bonding initially, intermetallic compounds (IMCs) occurred at the Al/Cu interface. After plastic deformation by rolling the laminated composites, the interface strip of IMCs broke and became discontinuous equiaxed particulates. Compared with roll bonding with heat treatment and diffusion bonding, the shear tensile strength of two-stage processed Al/Cu interface reached a maximum value equivalent to 90% of that of Al. Therefore, it is concluded that the diffusion rolling procedure yielded the highest strength of Al–Cu laminated composites.

Interfacial characteristics of Cu–Fe laminate fabricated by solid state welding

Abstract Solid state welding was employed to join low intersolubility metal couple Cu–Fe, and the microstructure and mechanical properties of the joints were investigated. The interface was free of defects. Scanning electron microscopy, energy dispersive spectrometry, atomic force microscopy and nanoindentation results revealed that a potential area of pseudo-binary alloy was present at the faying surface, where nanoscale particles were moved to the opposite side by facilitated diffusion. Owing to the mechanism of microcontact and facilitated diffusion, the interfacial strength was improved.