Effect of cooling rate on microstructure and microhardness of hypereutectic Al–Ni alloy

Carrara, André; Kakitani, Rafael; Garcia, Amauri; Cheung, Noé

doi:10.1007/s43452-020-00159-2

Cited by 13 publications

(5 citation statements)

References 46 publications

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“…Solute concentrations ranged from approximately ~2.8 wt.%Fe and ~5.6 wt.%Ni at the metal/mold interface to ~1.1 wt.%Fe and ~4.8 wt.%Ni at the top of the DS casting. A similar occurrence of slightly higher Ni concentrations at the base of the DS casting was also observed by Carrara et al [27] in an Al-8Ni alloy. This phenomenon can be attributed to the elevated cooling rates (30-50 K/s) experienced at the casting's base, along with the limited solubility of Ni in aluminum.…”

Section: Macrostructure and Macrosegregationsupporting

confidence: 85%

Fe-Containing Al-Based Alloys: Relationship between Microstructural Evolution and Hardness in an Al-Ni-Fe Alloy

Faria,

de Paula,

Silva

et al. 2023

Metals

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Recycled Al alloys not only offer environmental and economic benefits but also present a valuable base for the development of innovative materials, such as Al-Ni-Fe alloys. This work particularly focuses on the microstructural changes and hardness of an Al-5Ni-1Fe alloy (wt.%) solidified with an approximate 20-fold variation in cooling rates. For the various microstructural length scales obtained, only the eutectic regions exhibit a uniform pattern, with the eutectic colonies comprising an α-Al phase along with Al3Ni and Al9FeNi intermetallic compounds. It is shown that microstructural refinement can lead to a 36% increase in hardness. To represent this mathematically, hardness values are associated with the eutectic colony and intermetallic fiber spacings (λEC and λIF is, respectively) using experimental equations based on the Hall–Petch relationship and multiple linear regression. In addition, comparisons are undertaken with Al-5Ni and Al-1Fe (wt.%) alloy samples produced under the same conditions. The Al-5Ni-1Fe alloy exhibits higher hardness values than both the Al-5Ni and Al-1Fe binary alloys. Furthermore, the hardness of the ternary Al-Ni-Fe alloy is sensitive to microstructural refinement, a characteristic absent in the binary alloys. For λIF−1/2 = 1.56 µm−1/2 (coarser microstructure), the Al-5Ni-1Fe alloy exhibits a hardness of about 13% and 102% higher than that of the Al-5Ni and Al-1Fe alloys, respectively, while for λIF−1/2 = 1.81 µm−1/2 (finer microstructure), it demonstrates a hardness of approximately 39% and 147% higher as compared to that of the Al-5Ni and Al-1Fe alloys, respectively. Thus, this research provides experimental correlations that connect hardness, microstructure, and solidification thermal parameters, contributing to a better understanding for the design of as-cast Fe-contaminated Al-Ni-based alloys.

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Section: Macrostructure and Macrosegregationsupporting

confidence: 85%

Fe-Containing Al-Based Alloys: Relationship between Microstructural Evolution and Hardness in an Al-Ni-Fe Alloy

Faria,

de Paula,

Silva

et al. 2023

Metals

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“…2-At high cooling rate, the growth of primary Al3Ni is stopped and all structure is solidified like eutectic structure. 3-By increasing cooling rate, the structure will be finer [25]. Therefore, S15-1 was cooled down more quickly than the minimum cooling rate, but it was not high enough to stop growing of primary Al3Ni.…”

Section: Before Leachingmentioning

confidence: 99%

Production of a new 3D electrode skeleton of Ni with very high electrochemical surface area for oxygen evolution

Fakourihassanabadi

Guay

2021

Preprint

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Long and stable fibers (Tapes) of nickel with a thickness that can reach less than one hundred nanometers were produced through directional solidification of Ni-Al hypereutectic alloy on the surface of Ni and then, leaching the alloy in potassium hydroxide solution. Experimental results illustrated that the structure of the tapes is Raney nickel. In other words, a 3D structure consisting of a large number of Nano-dimensional tapes with a Nano-porous and Nano-crystalline structure was created. The activity of this structure was evaluated for oxygen evolution in alkaline media. The results showed that by increasing the number of Tapes per 〖cm〗^2 (density of Tapes), electrochemical surface area and double layer capacitance increase. As the density of Tapes increases, the OER overpotential decreases, but with further increase in density of Tapes, the OER overpotential increases again. Re-increase in overpotential was associated to trapping of oxygen bubbles. The best sample showed an overpotential 240 mV at 10 mA/〖cm〗^2 and 350 mV at 500 mA/〖cm〗^2. Also, this sample worked without any sign of degradation at 500 mA/〖cm〗^2 for 6 days (144 hours).

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“…The Al 3 Ni eutectic phases (Pnma crystal structure, with lattice parameters, a = 0.66115 nm, b = 0.73364 nm, and c = 0.48118 nm [10]) are distributed with a fine rod-like morphology, which tends to repel the matrix dislocations due to their higher elastic modulus [11]. Moreover, the interfaces between Al 3 Ni and the aluminum matrix are coherent, which increase the coarsening resistance at high temperature, and make the Al 3 Ni phases have excellent chemical and thermal stability up to 500 • C [12,13]. In addition, eutectic Al-Ni alloy has good castability due to the high-volume fraction of its Al 3 Ni phase (~10 vol%), and has a low tendency to hot crack.…”

Section: Introductionmentioning

confidence: 99%

Effect of Vanadium Addition on Solidification Microstructure and Mechanical Properties of Al–4Ni Alloy

Chen,

et al. 2024

Materials

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The effects of vanadium addition on the solidification microstructure and mechanical properties of Al–4Ni alloy were investigated via thermodynamic computation, thermal analysis, microstructural observations, and mechanical properties testing. The results show that the nucleation temperature of primary α-Al increased with increased vanadium addition. A transition from columnar to equiaxed growth took place when adding vanadium to Al–4Ni alloys, and the average grain size of primary α-Al was reduced from 1105 μm to 252 μm. When the vanadium addition was 0.2 wt%, the eutectic nucleation temperature increased from 636.2 °C for the Al–4Ni alloy to 640.5 °C, and the eutectic solidification time decreased from 310 s to 282 s. The average diameter of the eutectic Al3Ni phases in the Al–4Ni–0.2V alloy reduced to 0.14 μm from 0.26 μm for the Al–4Ni alloy. As the vanadium additions exceeded 0.2 wt%, the eutectic nucleation temperature had no obvious change and the eutectic solidification time increased. The eutectic Al3Ni phases began to coarsen, and the number of lamellar eutectic boundaries increased. The mechanical properties of Al–4Ni alloys gradually increased with vanadium addition (0–0.4 wt%). The Al–4Ni–0.4V alloy obtained the maximum tensile strength and elongation values, which were 136.4 MPa and 23.5%, respectively. As the vanadium addition exceeded 0.4 wt%, the strength and elongation decreased, while the hardness continued to increase. Fracture in the Al–4Ni–0.4V alloy exhibited ductile fracture, while fracture in the Al–4Ni–0.6V alloy was composed of dimples, tear edges, and cleavage planes, demonstrating mixed ductile–brittle fracture. The cleavage planes were caused by the primary Al10V and coarse Al3Ni phases at the boundary of eutectic cells.

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Effect of cooling rate on microstructure and microhardness of hypereutectic Al–Ni alloy

Cited by 13 publications

References 46 publications

Fe-Containing Al-Based Alloys: Relationship between Microstructural Evolution and Hardness in an Al-Ni-Fe Alloy

Fe-Containing Al-Based Alloys: Relationship between Microstructural Evolution and Hardness in an Al-Ni-Fe Alloy

Production of a new 3D electrode skeleton of Ni with very high electrochemical surface area for oxygen evolution

Effect of Vanadium Addition on Solidification Microstructure and Mechanical Properties of Al–4Ni Alloy

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