Properties of bulk amorphous alloys

The structure of amorphous alloys is the same as that of glassy materials, both of which are metastable. Its properties have been studied in different neighborhoods for nearly half a century. As the methods of preparing amorphous materials become more and more perfect, people can prepare amorphous alloy samples with regular shapes and sufficient sizes. People will further study the mechanical properties of amorphous alloys and apply them in engineering.

Compared with ordinary alloys, amorphous alloy materials have unique properties:

1. High elastic limit: the elastic strain limit can reach 2% in tension and compression, while the crystal material is less than 1%.

2. It has a high yield strength: as high as about 2GPa. At the same time, it is different from the tensile strength and yield strength of crystalline materials, and the yield strength of amorphous materials is greater than the tensile strength, usually both occur at the same time.

3. Fatigue performance: its crack growth behavior is similar to that of traditional ductile crystalline materials, that is, (a) the crack growth rate depends on the range of the applied stress intensity, (b) the load ratio and the role of crack closure are similar, (c) on the fatigue fracture surface Resilience fringes appear on the surface. Therefore, the relationship between the fatigue stress and the number of cycles of bulk amorphous alloys is different from that of ductile crystalline metals. The fatigue life is low and the dependence on the stress range is small. It can be observed only when the applied stress drops to 4% of the tensile stress. To its fatigue limit.

4. Higher hardness, the atoms of amorphous materials are arranged in a high-density packing together, the hardness is generally higher, the fracture toughness value of amorphous alloys KIC is higher than that of failure strengthened aluminum alloys (24～36MPam1/2), and commercial titanium The alloy is equivalent (54～98MPam1/2), about 60～70 MPam1/2.

In addition, amorphous has good stamping properties, superplasticity, good toughness and other mechanical properties.