Revealing the Precipitation Sequence with Aging Temperature in a Non-equiatomic AlCoCrFeNi High Entropy Alloy

Nandal, Vickey; Harun, Bushra; Sarvesha, R.; Singh, Sudhanshu; Huang, E-Wen; Chang, Young-Il; Yeh, An‐Chou; Jain, Jayant; Neelakantan, Suresh

doi:10.1007/s11661-021-06528-7

Cited by 18 publications

(5 citation statements)

References 20 publications

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“…Accordingly, the mechanical behavior of the as-cast Al 0.6 CoFeNiCr 0.4 was investigated after thermal treatment in the temperature range of 550e850 C for 24 h, and demonstrated that the formation and evolution of ordered B 2 phase in the course of ageing improved the mechanical properties [13]. The earlier investigations on AlCoCrFeNi [14] and Al 0.6 CoCrFeNi [15] HEAs, revealed that the B 2 precipitates were formed during the aging process due to the transformation of L1 2 nano-precipitates to B 2 needle shape precipitates, which is triggered by the higher thermodynamic stability of B 2 eNiAl precipitates. However, the previous research demonstrated that the formation of the needle shape B 2 phase in primary FCC can be observed through the long-term heat treatments at low-temperature range [16].…”

Section: Introductionmentioning

confidence: 97%

On the Short-Time Thermal Phase-Stability of As-Cast Alcocrfeni2.1 Eutectic High Entropy Alloy

et al. 2022

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Section: Introductionmentioning

confidence: 97%

On the Short-Time Thermal Phase-Stability of As-Cast Alcocrfeni2.1 Eutectic High Entropy Alloy

et al. 2022

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“…The high-temperature mechanical properties of Ni-based superalloys are nally controlled by the aging heat treatment, which determines the two-phase microstructure consisting of γ' precipitate and γ matrix [1][2][3] in the system. Currently, the aging treatment of alloys is carried out through conventional isothermal methods 4,5 . However, when examining different alloy systems such as Fe-Cu 6 , 2A14 Al 7 Al-Zn-Mg-Cu 8-10 , Al-Cu-Mg-Si 11 , Al-Zn-Mg 12 and Mg-4Y-2.5Nd-1.2Gd-0.5Zr 13 in the literature, it has been observed that non-isothermal aging (NIA) leads to enhanced mechanical properties compared to the conventional isothermal aging methods.…”

Section: Introductionmentioning

confidence: 99%

AI-Driven Aging Pattern Analysis for Improving 0.2% Proof Stress in Binary Ni-Al Alloys with γ – γ' Two-Phase Structure

Nandal,

Dieb,

Bulgarevich

et al. 2024

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This study presents the comprehensive analysis of flexible non-isothermal aging (NIA) patterns discovered through artificial intelligence (AI) to improve the mechanical strength (0.2% proof stress) in γ – γ' two-phase, binary Ni-Al alloys. In our recent investigation, we found that the AI algorithm could propose aging patterns with superior strength compared to conventional isothermal aging. In this current study, we continued our extensive exploration of AI methodologies, uncovering diverse patterns that also surpassed the isothermal aging benchmark. Remarkably, out of 2823 NIA schedules, we found 173 ones outperforming the isothermal aging benchmark. Furthermore, we conducted a detailed analysis of newly AI-discovered patterns. We identified two critical factors for strength improvement: exposure at 700 ℃ and the number of consecutive 700 ℃ exposures (optimally set at two), alongside non-consecutive steps (up to five). The insights gained from these findings may demonstrate the potential of AI-driven approaches to yield ideas on how to achieve improved strength in Ni-Al alloys.

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“…For example, changing the composition towards the nickel-rich region (AlCoCrFeNi 2.1 ) allows achieving simultaneous strength–ductility enhancement [ 16 ]. Extremely high strengths have been achieved in multiphase systems due to various strengthening mechanisms, such as particle hardening [ 17 ], precipitation hardening at aging [ 18 ] or solid solution strengthening [ 19 ]. In the latter case, the BCC phase with B2 precipitation in AlCoCrFeNi had an ultra-high hardness of 1124 Hv due to the enhanced solid solution strengthening effect.…”

Section: Introductionmentioning

confidence: 99%

Combustion Synthesis and Reactive Spark Plasma Sintering of Non-Equiatomic CoAl-Based High Entropy Intermetallics

et al. 2023

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The present work reports the direct production of a high-entropy (HE) intermetallic CoNi0.3Fe0.3Cr0.15Al material with a B2 structure from mechanically activated elemental powder mixtures. Fast and efficient combustion synthesis (CS), spark plasma sintering (SPS), and reactive SPS (RSPS) methods were used to synthesize the HE powders and bulks. The formation of the main B2 phase along with some amounts of secondary BCC and FCC phases are reported, and L12 intermetallic (CS scheme) and BCC based on Cr (CS + SPS and RSPS schemes at 1000 °C) were observed in all samples. The interaction between the components during heating to 1600 °C of the mechanically activated mixtures and CS powders has been studied. It has been shown that the formation of the CoNi0.3Fe0.3Cr0.15Al phase occurs at 1370 °C through the formation of intermediate intermetallic phases (Al9Me2, AlCo, AlNi3) and their solid solutions, which coincidences well with thermodynamic calculations and solubility diagrams. Compression tests at room and elevated temperatures showed that the alloy obtained by the RSPS method has enhanced mechanical properties (σp = 2.79 GPa, σ0.2 = 1.82 GPa, ε = 11.5% at 400 °C) that surpass many known alloys in this system. High mechanical properties at elevated temperatures are provided by the B2 ordered phase due to the presence of impurity atoms and defects in the lattice.

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Revealing the Precipitation Sequence with Aging Temperature in a Non-equiatomic AlCoCrFeNi High Entropy Alloy

Cited by 18 publications

References 20 publications

On the Short-Time Thermal Phase-Stability of As-Cast Alcocrfeni2.1 Eutectic High Entropy Alloy

On the Short-Time Thermal Phase-Stability of As-Cast Alcocrfeni2.1 Eutectic High Entropy Alloy

AI-Driven Aging Pattern Analysis for Improving 0.2% Proof Stress in Binary Ni-Al Alloys with γ – γ' Two-Phase Structure

Combustion Synthesis and Reactive Spark Plasma Sintering of Non-Equiatomic CoAl-Based High Entropy Intermetallics

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