Microstructural characteristics, mechanical properties and wear behavior of CuCrFeNiTi0.8Al1.2 high entropy alloy

The strength-ductility trade-off has been a long-standing dilemma in materials science,which limited the potential of many structural materials, high entropy alloys in particular. Here, we customized the microstructure by manipulating it, ultimately achieving an improvement in strength without sacrificing ductility, rather than increasing them separately. TEM and EBSD findings revealed that the as-cast CuCrFeNiTi 0.8 Al 1.2 alloy was composed of Ni-Al-Ti rich B 2 matrix, Fe-Ti rich dendrite phases and Cr-Fe rich spherical particles. Upon the introduction of annealing process, significant grain refinement was achieved. Additionally, the increase of annealing temperature led to the presence of secondary precipitated particles within the alloy. Vickers hardness test results indicated a significant increase in hardness as the annealing temperature rose from 514 HV for as-cast sample to 642 HV for 1000°C-24h sample. In addition, compressive test outcomes suggested that the annealed alloy indicates an increase of ∼32.7% in yield strength and an increase of ∼12.4% in fracture strength while maintaining super plastic. The excellent properties can be ascribed to the precipitation strengthening of ultrafine particles and the significant crystal lattice distortion strengthening in HEA. Importantly, this study provides valuable insights into enhancing the wear resistance and mechanical properties of HEAs, contributing to the development of advanced materials in engineering applications.