A series of alloy components with strong amorphous forming ability have been developed. The critical cooling rate of zircaloy based amorphous alloys is low to the lK/s level and can be easily prepared into three-dimensional bulk materials by copper mold casting and water quenching. It has been proved that the fracture behavior of bulk amorphous is closely related to the shear band, and the formation of the shear band is highly localized. It is generally believed that the main mechanism for forming localized shear bands is the reduction of viscosity at some inhomogeneity in metallic glass. In the process of sample compression, the micro cracks first start at a certain ー place and expand forward along the direction of shear band by tearing layer upon layer of shear band. This growth rate is very fast. When a large number of microcracks are connected to form a main crack, the rapid growth of the main crack will lead to the failure and fracture of the sample. Obviously, brittleness seriously restricts the wide application of bulk amorphous alloys as engineering materials. How to solve the brittleness of bulk amorphous alloys has been an important research direction in this field.
Zirconium alloys used in nuclear fuel assemblies of pressure water reactors are required not only to have low thermal neutron absorption cross section, high strength, good ductility, thermal conductivity and anti-radiation stability, but also to have excellent corrosion resistance and hydrogen absorption stability. Compared with zirconium alloys, zirconium based amorphous alloys have excellent radiation resistance and corrosion resistance. Unfortunately, zirconium-based amorphous alloys with good plasticity are limited to Zr-Ni-based bulk amorphous alloys. Because Ni can accelerate the hydrogen absorption of Zr and produce hydrogen embrittleness, it is necessary to develop a Zr-based bulk amorphous alloy without N1 and with good plasticity and nuclear performance requirements.
Microalloying can effectively improve the plasticity of bulk zirconium-based amorphous alloys. For example, Y. F. Sun et al. introduced CuZr martensitic phase into ZrCu Al bulk amorphous alloy by controlling the cooling rate, and prepared the bulk amorphous alloy matrix composite with martensitic phase in the amorphous alloy matrix, and its plastic deformation capacity was increased to 7.7%.
