Process optimization and microstructure of Ti3Zr1.5NbVAl0.25 high entropy alloy produced by directed energy deposition

Abstract

As an emerging materials preparation method, directed energy deposition (DED) has its unique advantages in the preparation of high entropy alloys (HEAs). However, improper process parameters can lead to numerous defects, affecting material properties. In this study, a Ti3Zr1.5NbVAl0.25 HEA was produced by DED. The effects of process parameters on single track cladding layer (STCL) were studied by response surface methodology (RSM), and the parameters were optimized accordingly. It is indicated that the microstructure of the STCL is composed of columnar and equiaxed crystals and the grain growth is parallel to the heat flux direction. 〈001〉//BD (building direction), 〈111〉//SD (scanning direction) and {100}〈001〉 textures were observed in molten pool. The microhardness of the molten pool measures 299.99 HV0.2, while the estimated Young's modulus and yield stress are 87.66 GPa and 945 MPa, respectively. This work provides unique insights into optimizing the DED process parameters of HEAs, further obtaining the solidification microstructure and mechanical properties of STCL.