Zr-bmg, And W_f / Zr-bmg Mechanical Properties Test

Bulk metallic glasses (BMGs) is a kind of new emerging materials with no long-rang order of atomic arrangements. The mechanical properties of both Zr based BMGs and the tungsten fiber reinforced metallic glass matrix composite (Wf/Zr-BMG) are studied experimentally. Five aspects are included.(1) Quasi-static and dynamic compressive experiments are performed on Zr-BMG at four temperatures from 77K to 473K. It shows that the yield stress is sensitive to strain rate and temperature. An typical vein-like pattern formed by the flow of the melted material is observed on the shear fracture surface, and an slurry like one is observed when the temperature rises to 473K.(2) As for W_f/Zr-BMG, we firstly studied the influences of infiltration temperature, fiber diameter (Φ) and volume fraction (V_f) to the properties of composite. It is found that the composite obtained under infiltration temperature of 711K with Φ=250μm, V_f=60% has the best performances in general. With V_f increasing, the strength and toughness of W_f/Zr-BMG are increased and the fracture mode of specimen is changed from shear to vertical cleavage with fiber buckling and splitting. This axial cracking runs from fiber to fiber along the interface in a zigzag path. The mixed failure mode of shear and vertical cleavage is found under dynamic loading.(3) The same strain rate and temperature sensitivity experiments are performed on W_f/Zr-BMG. The result indicate that the yield strength increases while the failure strain decreases with decreasing temperature. The dynamic compression shows that the yield stress is higher than that of the corresponding quasi-static compression. Vein-like patter is found again on the shear fracture surfaces, but the melted shear bands are more viscous when...