Which method allows for the formulation of unusual alloys in powder metallurgy?

The method that allows for the formulation of unusual alloys in powder metallurgy is through a controlled level of porosity. This approach enables the creation of materials with specific properties that might not be achievable through conventional alloying and casting methods.

In powder metallurgy, controlling the porosity of the final product can significantly impact mechanical and physical properties, including lightweight structures with high strength. By adjusting the amount of porosity, manufacturers can achieve desired performance characteristics in unusual alloys, such as improved thermal or electrical conductivity, reduced weight, and enhanced resistance to wear or corrosion.

Other methods listed do not focus specifically on creating unconventional alloys. Pressing is mainly about compacting the powder into a desired shape but does not intrinsically involve the formulation of exceptional compositions. Sintering, while crucial for solidifying pressed powders, is more about the bonding process than creating unique alloys. Controlled mixing and blending indeed influences the composition of the materials, but without the specific focus on porosity and its effects on the alloy's properties, it is less relevant to formulating unusual alloys in the context of powder metallurgy.