The Need

High entropy alloys (HEA) are a new class of multiple-principle-element alloys stabilized by large configurational entropy. HEA offer exceptional mechanical, chemical, and magnetic properties at room and elevated temperatures. Current efforts in the HEA field have focused on developing new materials with exceptional mechanical properties. Since HEA often consists of four or more principal elements, these alloys typically contain elements with high densities, such as Fe, Co, and Ni. However, dense elements can cause the overall alloy to be relatively heavy. There are also alloys with lighter weight, such as Ti-Al-V alloys and stainless steel, but these typically do not display the necessary strength. There remains a need for new metal alloys that have relatively high strength and relatively low weight.

The Technology

Researchers at The Ohio State University, led by Dr. Alan Luo, developed new Al-Cr-Ti-V based alloys displaying extremely high strength and improving upon other mechanical properties. These high entropy alloys are designed based on the CALculation of PHAse Diagrams (CALPHAD) thermodynamic calculations. Prepared by arc melting, the cast microstructures proves that a body-centered cubic (BCC) A2 solid solution is the dominant phase, which agrees with the CALPHAD calculations.

Commercial Applications

• High-strength structural materials
• Automotive

Benefits/Advantages

• Extremely high hardness ratio
• Improved specific strength
• Inexpensive materials