Every industrial metallic alloy has the same characteristic: they possess a crystalline structure in which atoms are organized. This crystalline structure may be advantageous in some ways but also limits possibilities both in terms of final properties and in terms of forming abilities of these alloys.
Amorphous metals (often referred as “metallic glasses”) are a suitable alternative to this crystalline structure. In amorphous metals, atoms are randomly distributed.
In the molten state, every metal has a disordered structure due to the constant motion of atoms. It is during the fast cooling of the liquid metal within a mold that the crystallization is avoided and the amorphous structure is obtained. Consequently, the solid structure is random and we obtain a metal with a structure close to the one in the liquid state. The lack of crystallization during casting leads to almost no shrinkage upon solidification. This means that the amorphous metal conforms exactly to the mold cavity and the accuracy of the molded part is comparable to the mold manufacturing precision. As a result, the molded part has both the same geometrical accuracy and surface finish as the mold and no post-molding operation is required to achieve the desired dimensional tolerances.
Obviously, the amorphous structure cannot be obtained for any alloy composition nor by using standard manufacturing processes. Nevertheless, there are many compositions of amorphous metals with many outstanding physical, mechanical and chemical properties. In addition, all the final properties are obtained directly after molding without post treatment, which is another advantage compared with crystalline metals.
The chemical composition significantly influences the properties of amorphous metals. VULKAM has already developed several amorphous alloys based on Zirconium, Copper, Titanium… It satisfies several needs in terms of mechanical resistance, non-magnetism, environment resistance, biocompatibity… Each composition is suitable for the manufacture of either surgical tools, micromechanical parts transmitting loads, micro-springs, implants, micro-fluidic components, watch components…
However, despite differences in their chemical composition, amorphous metals generally exhibit :
- Unmatched mechanical resistance: some amorphous metals developed by VULKAM are more than twice as resistant as Titanium alloys.
- Extremely high elastic (reversible) deformation: around 2%, twice as high as the best industrial spring alloys.
- High hardness (wear and scratch resistance): some amorphous metals developed by VULKAM are three times harder than stainless steel.
- Non-magnetism, biocompatibility, corrosion resistance…
- And many other custom properties !
The properties of different amorphous metal compositions can also be compared with other crystalline metals. The graphs below show certain ranges of amorphous metal properties that are grouped according to their major chemical constituents (Copper, Zirconium, Nickel…).
Amorphous metals made by VULKAM
VULKAM offers the widest range of amorphous metals and tailors the composition to the customer’s needs. VULKAM’s amorphous metals are composed mainly of either Zirconium, Copper, Hafnium, Nickel or Titanium.