| Abstract Scope |
From high temperature materials that may replace Ni-based superalloys to lightweight structural alloys, refractory compositionally complex alloys (R-CCAs) containing elements from Groups IV through VI of the periodic table represent an exciting new class of alloys for future exploitation in next generation technologies. R-CCAs are most often single-phase BCC, or a majority BCC also containing secondary phases such as B2, Laves, and others. BCC alloys behave fundamentally different than FCC-based alloys, such as Al- or Ni-based superalloys, including the thermodynamically higher-order BCC-B2 phase relationship and thermally activated dislocation motion governing plastic deformation even at room temperature, which leads to the ductile-to-brittle transition exhibited by most BCC materials. This work explores the thermodynamics of these materials, including the implications of the higher-order nature of the BCC-B2 transformation on precipitation strengthening and the effects of thermodynamics on plastic deformation and transformation-induced plasticity (TRIP) behavior. |