A New Class of Materials Based on Nanoporous High Entropy Alloys with Outstanding Properties

Abstract: Nanoporous metals with a random, bicontinuous structure of both pores and ligaments exhibit many unique mechanical properties, but their technical applications are often limited by their intrinsic brittleness under tensile strain triggered by fracture of the weakest ligaments. Here, we use molecular dynamics simulations to study the mechanical behavior and thermal stability of two different bicontinuous nanoporous high entropy alloys, Al0.1CoCrFeNi and NbMoTaW. To isolate the properties related to the nanoporous nature of our samples, we also studied the corresponding bulk and nanocrystalline systems. The results demonstrate that the specific modulus of nanoporous HEAs are 2 to 3 times greater than that of single element nanoporous materials with specific strength reaching values 5 to 10 times higher, comparable to bulk metals with the highest specific strength. Bicontinuous HEAs also displayed excellent resistance to thermal degradation as evidenced by the absence of coarsening ligaments up to temperatures of 1273 K which ensures the durability and reliability in high-temperature applications. The findings uncover unprecedented mechanical and thermal properties of bicontinuous nanoporous high entropy alloys, paving the way for their promising utilization in advanced engineering and structural applications.