Laser metal deposition of compositionally graded TiZrNbTa refractory high-entropy alloys using elemental powder blends

By Henrik Dobbelstein, E. Gurevich, Easo P. George, A. Ostendorf, G. Laplanche. Additive Manufacturing, 2019

161 citations recorded by the source corpus.

Abstract In the present study, laser metal deposition (LMD) was used to produce compositionally graded refractory high-entropy alloys (HEAs) for screening purposes by in-situ alloying of elemental powder blends. A compositional gradient from Ti25Zr50Nb0Ta25 to Ti25Zr0Nb50Ta25 is obtained by incrementally substituting Zr powder with Nb powder. A suitable strategy was developed to process the powder blend despite several challenges such as the high melting points of the refractory elements and the large differences in melting points among them. The influence of the LMD process on the final chemical composition was analyzed in detail and the LMD process was optimized to obtain a well-defined compositional gradient. Microstructures, textures, chemical compositions and mechanical properties were characterized using SEM, EBSD, EDX, and microhardness testing, respectively. Compositions between Ti25Zr0Nb50Ta25 and Ti25Zr25Nb25Ta25 were found to be single-phase bcc solid solutions with a coarse grain microstructure. Increasing the Zr to Nb ratio beyond the equiatomic composition results in finer and harder multiphase microstructures. The results shown in the present study clearly show for the first time that LMD is a suitable processing tool to screen HEAs over a range of chemical compositions.

Subfields: Aerospace Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/cda681442c6dca4eecaa53be0251470252d75418

How researchers see this paper

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In Aerospace Engineering

1. R. Ritchie
2. Dierk Raabe
3. Easo P. George
4. Zhiming Li
5. P. K. Liaw
6. Hyoung-Seop Kim
7. Shiteng Zhao
8. W. A. Curtin

In Mechanical Engineering

1. R. Ritchie
2. Dierk Raabe
3. Easo P. George
4. C. Tasan
5. Zhiming Li
6. P. K. Liaw
7. Franz Roters
8. O. A. Zambrano

Citations in the corpus

• Research status of laser additive manufacturing for metal: A review (2021, background): “[199] Dobbelstein H, Gurevich EL, George EP, Ostendorf A, Laplanche G.”
• High-entropy alloys (2019, methodology): “Subsequently, [111]-oriented, [149]-oriented, [122]-oriented and [123]-oriented single crystals were tested in tension and CRSS values of ~55 MPa and 150 MPa were obtained at room temperature and 77 K, respectively, again independent of orientation96.”