| This paper mainly studied the technological parameters and the performance of TiNi wires reinforced aluminum alloy matrix composite(TiNi/Al) on the impact load. The quasi-static and dynamic mechanics properties of Ti Ni alloys were investigated at room temperature by means of INSTRON apparatus and a split Hopkinson pressure bar technique, respectively. TiNi/Al composite was fabricated by hot pressing method,and the deformation behavior, microstructure evolution of the composite fabricated with best technical parameters were studied through microscopic analysis methods like XRD, DSC, OM, SEM. Damage and fracture of TiNi/Al composite plate penetrated vertically by 7.62 mm wear incendiary were investigated. The results show:(1)The original phase of TiNi material were mainly B2 austenite phase, small amount of B19' matensite phase and Ti3Ni4 at room temperature, and its transformation points were-65.3?(Mf),-37.1?(Ms),-33.9?(As),-4.5?(Af), respectively. Quasi-static compression true stress-strain curve showed obviously four stages deformation characteristics, which was not occured on quasi-tensile and dynamic compression stress-strain curves, but stress induced martensite phase transformation happened in all the deformation process, grains were full of parallel striped microstructure after deformation.The main fracture mode of TiNi alloy during quasi-static tensile deformation was considered as the cleavage fracture and with accumulation fracture. The fracture mode of TiNi alloy during quasi-static and dynamic compressive mainly attributed to cleavage fracture, showed obvious brittle fracture characteristics.(2)In the range of researched process parameters, elements diffusion between TiNi wires and Al matrix were more fully with the increase of temperature and heat preservation time, and the interface combination was better. When other conditions remained unchanged, with the extension of heat preservation time, quasi-static tensile yield strength and tensile strength also showed a trend of increase; yield strength and tensile strength of composites increased obviously with the increase of temperature, but when temperature increased to over 600?, the mechanical properties basically remained unchanged. The best technology parameters were 600?, 45 MPa, 180 min.(3)The yield process of TiNi/Al composite was yield when tensile stress increased to 175~230MPa, and the yield strength was lower than original Al matrix; then with the increase of flow stress, deformation increasing until fracture failure. TiNi/Al composite sample had certain spallation after quasi-static tensile test, the fracture morphology of Al matrix was a dimple pattern with features of plastic fracture, and the fracture of TiNi wires had mixed-rupture characteristics of cleavage and dimples.(4)TiNi wires in the TiNi/Al composite precipitate intermetallic compounds like Ni4Ti3, Ti2 Ni during hot pressing process. As the generation of precipitated phase caused the difference of grains' inside stress field, multiple endothermic peak and exothermic peak appeared on the DSC curves of Ti Ni alloy, and phase transformation proceed on several stages.(5)Mechanical properties of Al matrix decreased after hot pressing process. Quasi-static tensile strength of TiNi/Al composite increased with the increase of TiNi wire volume fraction, it was higher than the original Al alloy when the TiNi wire volume fraction increased to 14.4%.(6)Quasi-static compression and dynamic compression properties of TiNi/Al composite are anisotropic; and with the increase of TiNi wire volume fraction, quasi-static and dynamic compression yield strength increases, and the mechanical properties of anisotropic also increase.(7)Damage and fracture of TiNi/Al compoaite penetrated vertically by 7.62 mm wear incendiary have been investigated. The macroscopic damage feature of composite showed thermoplastic damage behavior, and main damage forms is plastic deformation of Al matrix, TiNi wires and interface cracking, didn't appear adiabatic shear band. |
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