Hetero-deformation-induced hardening of AlNbTaTiV refractory high-entropy alloy particles through mechanical alloying
Bibliographic record
Abstract
In this work, lightweight refractory high-entropy alloy (RHEA) particles (AlNbTaTiV) were manufactured through different mechanical alloying (MA) techniques and exhibited unique multi-phase structures. During the milling process, the phase formation and chemical homogenization mechanisms were found to be mainly influenced by MA routes and milling times. After 24 h of milling time, both MA routes (i.e., conventional and sequential) formed unique body-centered cubic (BCC) phases, identified as Ta-rich (BCC1), V-rich (BCC2), and Nb-rich (BCC3) phases, which are responsible for the significant strengthening of the RHEA particles. Then, an interesting mechanism was observed during the sequential MA after the addition of V to the AlNbTaTi system (predominantly BCC1 phase). A large spike in lattice parameter and dislocation density was detected, resulting in approximately a two-fold increase in hardness, a phenomenon triggered by the limited dissolution of V in BCC1, leading to lattice strains. Generally, the MAed AlNbTaTiV RHEA particles exhibited high nanoindentation hardness values of 12.80 GPa and 7.90 GPa after conventional and sequential MA, respectively. These high hardness values (i.e., higher than values available in literature) are linked to the multi-phase system with a heterogeneous structure, leading to the strengthening effects via hetero-deformation-induced hardening. In addition to lightweighting, the Al addition resulted in highly negative mixing enthalpies, causing hierarchical chemical fluctuations and eventually promoting strength. In general, this research sheds light on the potential of MAed AlNbTaTiV RHEA particles with heterogeneous structure-induced hardness as a candidate feedstock material for various consolidation techniques and thermal spray processes, such as cold spray additive manufacturing. • Mechanical alloying produced multi-phase, hetero-structured AlNbTaTiV particles. • Milling for 24 h resulted in the formation of Ta-, V-, and Nb-rich BCC phases. • Microstructural analysis per milling time revealed the stages of particle formation. • Sequential addition of Ti and V influenced the phase formation and particle hardness. • Hetero-deformation-induced hardening in AlNbTaTiV particles led to high hardness.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".