Exploration Research On Improving Compressive Plasticity Of La-based Bulk Metallic Glass Using Continuous Tungsten Fiber At Room Temperature

Metallic glass(also known as amorphous alloy)has the unique atomic structure of long-range disorder and short-range order,which shows excellent mechanical properties,such as high strength,high hardness and good wear resistance.However,the severe room temperature brittle fracture of metal glass makes it very limited in engineering applications.China has abundant reserves of rare earth minerals,and the output is the highest in the world.La and Ce as the most abundant in the crust of two kinds of rare earth elements,often associated with other rare earth elements of rare earth minerals.It is necessary to transform the resources advantage into industrial advantage through further research.In this paper,first exploration research on improving compressive plasticity of La-based bulk metallic glass(BMG)was carried out using continuous tungsten fiber at room temperature.By analyzing the properties of La-BMG and the interfacial bonding and precipitating phase of Wf/La-BMG composites,the Wf/La-BMG composites with obvious compression plasticity at room temperature were explored.The high strength composites was successfully obtained under low strength matrix condition:La-BMG(only 628MPa)continuous Wf(?2300MPa)composites have high strength(2814MPa),which is superior to Zr-BMG(upto 1900MPa)continuous Wf composites strength(?2600MPa).The main results are as follows:(1)The analysis of La-based BMG by the DSC and the variable temperature XRD curve shows that:as the temperature rises,the ?-La phase began to precipitate,and then the Al3La phase was precipitated out.The fracture strength of La-BMG at room temperature is about 628MPa,which shows an adiabatic shear fracture with a pulse pattern.(2)For the first time,we explored the Wf/La-BMG composites with large size,good interfacial bonding and uniform density.The composite interface was bonded by the way of atomic mutual diffusion and physical dissolution(thickness?10 m).The compressive strength of Wf/La-BMG composites is as high as 2814MPa,which is superior to that of Wf/Zr-BMG composites(?2600MPa).Meanwhile,the room temperature compressive plasticity(total strain 10.3%)is obtained,showing a plastic fracture mode of tungsten filament tissue tear.(3)With the increase of the volume fraction(V)of the Wf enhanced phase,the compressive strength and total strain of the Wf/La-BMG composites are increased.When Wf volume fraction is 50%,it is a brittle fracture mode.When Wf volume fraction is 75%,the strain can reach 13.5%and the strength is 1929MPa,and the fracture mode changes to the characteristics of the tearing of tungsten filament tissue.At the same time,the relationship between Wf volume fraction and properties was established.