Micro-Structure and Mechanical Properties of 2A97 Al-Li Alloy Cast by Low-Frequency Electromagnetic Casting
Abstract
:1. Introduction
2. Experimental
2.1. Material Preparation
2.2. Characterizations and Testing
3. Results
3.1. Effect of Electromagnetic Field on Micro-Structure of As-Cast Alloys
3.2. Effect of Electromagnetic Field on Defects of As-Cast Alloys
3.3. Effect of Low-Frequency Electromagnetic Field on Solid Solubility of Alloying Element within Grains of As-Cast Alloys
3.4. Effect of Low-Frequency Electromagnetic Field on Micro-Structure and Precipitate of Aged Alloys
3.5. Effect of Low-Frequency Electromagnetic Field on Mechanical Properties of Aged Alloys
4. Discussion
4.1. The Mechanism of Effect of LFEC on the Micro-Structure
4.2. The Mechanism of Effect of LFEC on the Solid Solubility
5. Conclusions
- (1).
- The micro-structure of ingots was remarkably refined by using LFEC. The average grain size of a one-half radius region of a cross section of ingots underwent refinement from 303.2 µm in conventional DC casting to 119.6 µm in LFEC with 150 A/10 Hz, and the grain morphology changed from coarse and rose dendrites to uniform and fine equiaxed structures.
- (2).
- The number of casting defects decreased remarkably in the as-cast ingot prepare by LFEC.
- (3).
- The solid solubility of alloying elements within grains in the as-cast ingot prepared by LFEC was significantly enhanced.
- (4).
- The T1 phases in the aged alloy prepared by LFEC became finer and exhibited a higher density and more uniform distribution.
- (5).
- After applying a low frequency electromagnetic field during DC casting, the mechanical properties of 2A97 aged alloys were improved significantly. The maximum ultimate tensile strength, 595.58 MPa, the yield strength of 494.31 MPa, and the elongation of 8.47% was obtained when the parameters of LFEC were 10 Hz and 150 A.
Author Contributions
Funding
Conflicts of Interest
References
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Element | Cu | Li | Mg | Mn | Zr | Ti | Be | Al |
---|---|---|---|---|---|---|---|---|
Nominal | 2.0–3.2 | 0.8–2.3 | 0.25–0.8 | 0.20–0.60 | 0.08–0.20 | 0.001–0.10 | - | Bal. |
Analysed | 3.05–3.26 | 1.35–1.40 | 0.38–0.45 | 0.38–0.42 | 0.10–0.12 | 0.05 | 0.005 | Bal. |
Casting Condition | Areal Fraction of Defects | Number of Defects |
---|---|---|
DC casting | 0.45 ± 0.29% | 149.7 ± 45.1 |
10 Hz/150 A | 0.10 ± 0.04% | 33.0 ± 12.6 |
Miller Indices | Magnetic Field | 2θ/° | a/nm | Δa/nm |
---|---|---|---|---|
(111) | DC casting | 38.4872 | 4.0481 | −0.0019 |
10 Hz/50 A | 38.5062 | 4.0462 | −0.0038 | |
10 Hz/100 A | 38.5782 | 4.0389 | −0.0110 | |
10 Hz/150 A | 38.5777 | 4.0389 | −0.0110 | |
(200) | DC casting | 44.7142 | 4.0502 | −0.0002 |
10 Hz/50 A | 44.7217 | 4.0495 | −0.0005 | |
10 Hz/100 A | 44.7487 | 4.0472 | −0.0028 | |
10 Hz/150 A | 44.8102 | 4.0419 | −0.0080 | |
(220) | DC casting | 65.1062 | 4.0491 | −0.0009 |
10 Hz/50 A | 65.1427 | 4.0471 | −0.0029 | |
10 Hz/100 A | 65.1622 | 4.0460 | −0.0040 | |
10 Hz/150 A | 65.1862 | 4.0447 | −0.0053 | |
(311) | DC casting | 78.2342 | 4.0494 | −0.0006 |
10 Hz/50 A | 78.2437 | 4.0490 | −0.0010 | |
10 Hz/100 A | 78.2982 | 4.0466 | −0.0038 | |
10 Hz/150 A | 78.3302 | 4.0452 | −0.0048 |
Magnetic Field | a/nm | Δa/nm |
---|---|---|
DC casting | 4.0492 | −0.0009 |
10 Hz/50 A | 4.0480 | −0.0020 |
10 Hz/100 A | 4.0447 | −0.0054 |
10 Hz/150 A | 4.0452 | −0.0073 |
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Wang, F.; Wang, X.; Cui, J. Micro-Structure and Mechanical Properties of 2A97 Al-Li Alloy Cast by Low-Frequency Electromagnetic Casting. Metals 2019, 9, 822. https://doi.org/10.3390/met9080822
Wang F, Wang X, Cui J. Micro-Structure and Mechanical Properties of 2A97 Al-Li Alloy Cast by Low-Frequency Electromagnetic Casting. Metals. 2019; 9(8):822. https://doi.org/10.3390/met9080822
Chicago/Turabian StyleWang, Fuyue, Xiangjie Wang, and Jianzhong Cui. 2019. "Micro-Structure and Mechanical Properties of 2A97 Al-Li Alloy Cast by Low-Frequency Electromagnetic Casting" Metals 9, no. 8: 822. https://doi.org/10.3390/met9080822