Equal channel angular extrusion (ECAE) process was a deep pure shear deformation method for structural materials, developed in early 90s. ECAE technique has been successfully applied to several pure metals and alloys to refine the microstructure and improve the mechanical properties of materials. In the present paper, TiNi shape memory alloys have been treated by ECAE process. The effects of ECAE process on microstructures and transformation behaviors have been investigated. The initial coarse grains of TiNi alloy were refined after two passes of ECAE processes and short annealing at 1023 K. Transformation temperatures of TiNi alloy sharply decreased after two ECAE processes, then rapidly rose back when annealed at 773K for 2h.

The friction and wear properties under impact load and dry friction conditions of metal2plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear2resistance.

Three types of surface modifiers, N-β-aminoethyl-y[1]-aminopropyltrimethoxysilane coupling agent (SGS), a mixture of silane and rare earth elements (SGS/RES), and rare earth elements surface modifier (RES), were used to treat the glass fiber surface. Tensile tests of glass fiber–reinforced polytetrafluoroethylene (GF/PTFE) composites with different surface treatment conditions, surface modifiers, and glass fiber content were carried out. Finally, the fracture surface morphologies of GF/PTFE composites were investigated using scanning electron microscopy. Experimental results showthat the tensile properties of the treated GF/PTFE composite increased compared with those of the untreated one. RES is superior to SGS/RES and SGS modifiers in promoting interfacial adhesion between the glass fiber and PTFE because of the effects of rare earth elements on the compatibility. Meanwhile, the optimum contents of rare earth elements for the improvement of the tensile properties of GF/PTFE composite were obtained for RES and SGS/RES modifiers. The interfacial adhesion of the GF/ PTFE composites treated with RES or SGS/RES modifiers was mainly controlled by the contents of rare earth elements. The tensile properties of the GF/PTFE composites improved considerably when the content of rare earth elements in surface modifiers was 0.2-0.4wt%, and the optimumtensile performance of GF/PTFE composites was obtained at 0.3wt% RE content.

Solutions of rare earth modifier (RES) and epoxy chloropropane (ECP) grafting modification method were used for the surface treatment of aramid fiber. Tensile properties of both the aramid/epoxy composites and single fibers were tested. The effects of RES concentration on tensile properties of aramid/epoxy composites were investigated in detail to explore an optimum amount of rare earth elements in solution for modifying aramid fiber. The fracture surface morphologies of tensile specimens were observed and analyzed with the aid of SEM. The experimental results show that rare earth treatment is superior to ECP grafting treatment in promoting interfacial adhesion between the aramid fiber and epoxy matrix. Meanwhile, the tensile strengths of single fibers were almost not affected by RES treatment. The optimum performance is obtained when the content of rare earth elements is 0.5 wt %.

An investigation of the effect of rare earth elements (RE) on erosion resistance of nitrided 40Cr steel is carried out using an erosion test rig in a water-based slurry with quartz particles. Results indicate that a significant improvement occurs in erosion resistance of nitrided 40Cr steel by introducing RE in nitriding processes comparing conventional nitriding processes. Measurement of physical properties exhibits that both hardness and toughness of nitrided 40Cr steel increase in the case using RE-nitriding processes comparing the conventional. Metallurgical microscopy reveals that there is a transformation from a coarse to a fine metallurgical microstructure in the case and an increase in the thickness of white layer on the top of case attributed to an introduction of RE in nitriding, which attributed to an improvement in erosion resistance and physical properties. EDX analysis shows that RE diffuse into the case of 40Cr steel in nitriding process as a result of appearance of micro-alloy. Microscopy revealed that the furrow-like peeling from plastic deformation of material is predominant erosion mechanism of RE nitrided 40Cr steel while the furrow-like peeling with initial cross crack and large grinding peelings takes place predominantly in tests of conventionally-nitrided ones, which results in a significant difference in erosion resistance.