| Bulk metallic glasses exhibit unique properties and they have been paid much attention. In this paper, W fiber/Zr-based amorphous composite was investigated, the major results are as follows:W fiber/Zr-based amorphous composite was fabricated by a pressure infiltrating cast method; its mechanical prosperities and deformation behaviors were investigated. The results showed that average compressive fracture strength and plasticity of W fiber/Zr-based amorphous composite were 2750MPa and 29% respectively at room temperature. The main fracture mode of the composite was splitting along loading direction. The reason of the increase of the plastic deformation is that the W fibers restricted shear band propagation and promoted the generation of the multiple bands.After the samples were heat treated at the temperatures of 100℃, 300℃, 340℃and 390℃, the compression tests of W fiber/Zr-based amorphous composite were carried out at the strain rate of 2×10-4s-1 ,2×10-3s-1 and 2×10-2s-1 respectively. The heat treatment temperature had no remarkable effect on the mechanical properties of W fiber/Zr-based amorphous composite at the same strain rate.When the heat treatment temperatures were 100℃and 300℃respectively, both of the fracture strength and the plasticity of the composite decreased with the increase of the strain rate. When the heat treatment temperatures were 340℃and 390℃, with the increase of the strain rate, the fracture strength of the composite did not change too much but the plasticity decreased.The compression tests of W fiber/Zr-based amorphous composite were carried out at the temperatures of -100℃,0℃,150℃,250℃and 310℃. With the increase of the temperature, the young's modulus, yield strength and fracture strength decreased, accompanied with increased plasticity. The main fracture mode of W fiber/Zr-based amorphous composite was splitting along loading direction at the temperatures of -100℃and 0℃; while a mixed fracture mode of splitting along loading direction and twist was found at the temperatures of 150℃,250℃,310℃.The impact properties of W fiber/Zr-based amorphous composite were investigated at the temperatures of -60℃,-40℃,-20℃,0℃and 20℃. The main fracture modes were interface failure and brittle fracture of tungsten fiber. The fracture appearance could be divided into fracture area and impact area; the coverage of the facture area was up to 80% and the severest fracture area was found in the impact area. With the increase of the temperature, the impact energy increased from 0.8J to 1.2J and impact toughness increased from 47KJ /m2 to 69KJ/m2.The three-point bending properties of W fiber/Zr-based amorphous composite were investigated at room temperature. The fracture pattern was brittle fracture in the three-point bending experiment; while asymmetry separation of the interface between tungsten fiber and metallic glass can often be seen in the triangular area. The severest fracture occurred in the area where the indenter contacted the sample.
|
PDF Full Text Request