Acta Metallurgica Sinica (English Letters) ›› 2019, Vol. 32 ›› Issue (12): 1549-1564.DOI: 10.1007/s40195-019-00922-2
所属专题: 2019年铝合金专辑
• • 上一篇
收稿日期:
2019-03-01
修回日期:
2019-04-18
出版日期:
2019-12-10
发布日期:
2019-11-25
Hua-Ping Tang1, Qu-Dong Wang1(), Chuan Lei1, Kui Wang1, Bing Ye1, Hai-Yan Jiang1, Wen-Jiang Ding1,2
Received:
2019-03-01
Revised:
2019-04-18
Online:
2019-12-10
Published:
2019-11-25
. [J]. Acta Metallurgica Sinica (English Letters), 2019, 32(12): 1549-1564.
Hua-Ping Tang, Qu-Dong Wang, Chuan Lei, Kui Wang, Bing Ye, Hai-Yan Jiang, Wen-Jiang Ding. Effect of Cooling Rate on Microstructure and Mechanical Properties of Sand-Casted Al-5.0Mg-0.6Mn-0.25Ce Alloy[J]. Acta Metallurgica Sinica (English Letters), 2019, 32(12): 1549-1564.
Mg | Mn | Ce | Si | Fe | Al |
---|---|---|---|---|---|
4.91 | 0.67 | 0.23 | 0.29 | 0.10 | Bal. |
Table 1 Chemical composition of the as-cast alloy (wt%)
Mg | Mn | Ce | Si | Fe | Al |
---|---|---|---|---|---|
4.91 | 0.67 | 0.23 | 0.29 | 0.10 | Bal. |
Fig. 2 Cooling curves of the as-cast Al-5.0Mg-0.6Mn-0.25Ce alloys with different thicknesses a and the cooling curve (red solid line) and the corresponding first derivative (blue dashed line) of the as-cast alloy with a thickness of 10 mm b
Thickness (mm) | Rc (K/s) | ?T (°C) | ?t (s) | Al10Mn2Ce | α(Al) | Mg2Si | |||
---|---|---|---|---|---|---|---|---|---|
TLiq (°C) | tLiq (s) | T2 (°C) | t2 (s) | T3 (°C) | t3 (s) | ||||
50 | 0.22 | 69.7 | 419.1 | 654.2 | 15.2 | 626.4 | 31.2 | 556.7 | 450.3 |
25 | 0.33 | 69.8 | 292.3 | 656.1 | 11.5 | 626.5 | 20.0 | 556.6 | 312.3 |
10 | 1.39 | 79.0 | 71.6 | 657.1 | 4.3 | 629.2 | 9.6 | 550.2 | 81.4 |
5 | 7.65 | 63.9 | 8.4 | - | - | 614.8 | 2.5 | 550.9 | 10.8 |
Table 2 Solidification parameters of as-cast alloys with different thicknesses (T2: the formation temperature of α(Al); t2: the formation time of α(Al); T3: the formation temperature of Mg2Si; t3: the formation time of Mg2Si)
Thickness (mm) | Rc (K/s) | ?T (°C) | ?t (s) | Al10Mn2Ce | α(Al) | Mg2Si | |||
---|---|---|---|---|---|---|---|---|---|
TLiq (°C) | tLiq (s) | T2 (°C) | t2 (s) | T3 (°C) | t3 (s) | ||||
50 | 0.22 | 69.7 | 419.1 | 654.2 | 15.2 | 626.4 | 31.2 | 556.7 | 450.3 |
25 | 0.33 | 69.8 | 292.3 | 656.1 | 11.5 | 626.5 | 20.0 | 556.6 | 312.3 |
10 | 1.39 | 79.0 | 71.6 | 657.1 | 4.3 | 629.2 | 9.6 | 550.2 | 81.4 |
5 | 7.65 | 63.9 | 8.4 | - | - | 614.8 | 2.5 | 550.9 | 10.8 |
Fig. 4 Optical microstructures of the as-cast Al-5.0Mg-0.6Mn-0.25Ce alloys under different cooling rates: a 0.22 K/s; b 0.33 K/s; c 1.39 K/s; d 7.65 K/s
Thickness (mm) | Rc (K/s) | SDAS (μm) | Area fraction (%) | |
---|---|---|---|---|
α(Al) Dendrite | Al3Mg2 phase | Mn-rich phase | ||
50 | 0.22 | 94.8?±?13.2 | 21.5?±?4.6 | 1.46?±?0.15 |
25 | 0.33 | 75.7?±?12.4 | 20.8?±?3.8 | 1.40?±?0.11 |
10 | 1.39 | 44.8?±?9.5 | 8.7?±?1.3 | 0.76?±?0.10 |
5 | 7.65 | 27.3?±?5.5 | 6.6?±?0.9 | 0.67?±?0.08 |
Table 3 SDAS of α(Al) dendrites, area fraction (%) of Al3Mg2 and Mn-rich phases in the as-cast Al-5.0Mg-0.6Mn-0.25Ce alloys produced at different cooling rates
Thickness (mm) | Rc (K/s) | SDAS (μm) | Area fraction (%) | |
---|---|---|---|---|
α(Al) Dendrite | Al3Mg2 phase | Mn-rich phase | ||
50 | 0.22 | 94.8?±?13.2 | 21.5?±?4.6 | 1.46?±?0.15 |
25 | 0.33 | 75.7?±?12.4 | 20.8?±?3.8 | 1.40?±?0.11 |
10 | 1.39 | 44.8?±?9.5 | 8.7?±?1.3 | 0.76?±?0.10 |
5 | 7.65 | 27.3?±?5.5 | 6.6?±?0.9 | 0.67?±?0.08 |
Fig. 6 SEM micrographs showing effect of the cooling rate on the secondary phases in the as-cast Al-5.0Mg-0.6Mn-0.25Ce alloys: a 0.22 K/s; b 0.33 K/s; c 1.39 K/s; d 7.65 K/s; e corresponding EDS results of points 1, 2 and 3
Point | Al | Mg | Mn | Ce | Fe | Si | Identified phase |
---|---|---|---|---|---|---|---|
51.05 | 32.12 | 0 | 0 | 0.45 | 16.38 | Mg2Si | |
77.49 | 1.39 | 5.35 | 0.04 | 11.41 | 4.38 | α-Al24(Mn,Fe)6Si2 | |
78.43 | 7.69 | 9.83 | 3.51 | 0.54 | 0 | Al10Mn2Ce | |
77.94 | 1.74 | 6.31 | 0.02 | 10.35 | 3.63 | α-Al24(Mn,Fe)6Si2 | |
80.54 | 7.53 | 8.00 | 3.41 | 0.52 | 0 | Al10Mn2Ce | |
78.38 | 1.65 | 6.15 | 0 | 9.94 | 3.88 | α-Al24(Mn,Fe)6Si2 | |
80.99 | 7.53 | 7.75 | 3.21 | 0 | 0 | Al10Mn2Ce | |
77.30 | 3.37 | 7.38 | 0.10 | 8.13 | 3.72 | α-Al24(Mn,Fe)6Si2 | |
81.88 | 7.74 | 7.15 | 3.23 | 0 | 0 | Al10Mn2Ce |
Table 4 EDS results of the secondary phases shown in Fig. 6 (at%)
Point | Al | Mg | Mn | Ce | Fe | Si | Identified phase |
---|---|---|---|---|---|---|---|
51.05 | 32.12 | 0 | 0 | 0.45 | 16.38 | Mg2Si | |
77.49 | 1.39 | 5.35 | 0.04 | 11.41 | 4.38 | α-Al24(Mn,Fe)6Si2 | |
78.43 | 7.69 | 9.83 | 3.51 | 0.54 | 0 | Al10Mn2Ce | |
77.94 | 1.74 | 6.31 | 0.02 | 10.35 | 3.63 | α-Al24(Mn,Fe)6Si2 | |
80.54 | 7.53 | 8.00 | 3.41 | 0.52 | 0 | Al10Mn2Ce | |
78.38 | 1.65 | 6.15 | 0 | 9.94 | 3.88 | α-Al24(Mn,Fe)6Si2 | |
80.99 | 7.53 | 7.75 | 3.21 | 0 | 0 | Al10Mn2Ce | |
77.30 | 3.37 | 7.38 | 0.10 | 8.13 | 3.72 | α-Al24(Mn,Fe)6Si2 | |
81.88 | 7.74 | 7.15 | 3.23 | 0 | 0 | Al10Mn2Ce |
Fig. 8 Optical microstructures of the T4-treated Al-5.0Mg-0.6Mn-0.25Ce alloys produced at different cooling rates: a 0.22 K/s; b 0.33 K/s; c 1.39 K/s; d 7.65 K/s
Fig. 9 SEM micrographs and the corresponding EDS mapping of Mg element of Al-5.0Mg-0.6Mn-0.25Ce alloys fabricated at a cooling rate of 0.22 K/s under different states: a, b as-cast; c, d T4-treated
Thickness (mm) | Rc (K/s) | SDAS (μm) | Area fraction (%) | |
---|---|---|---|---|
α(Al) dendrites | Al3Mg2 phase | Mn-rich phase | ||
50 | 0.22 | 100.8?±?15.2 | ~?0 | 1.43?±?0.16 |
25 | 0.33 | 79.7?±?12.4 | ~?0 | 1.38?±?0.13 |
10 | 1.39 | 50.8?±?9.4 | ~?0 | 0.72?±?0.10 |
5 | 7.65 | 31.3?±?5.7 | ~?0 | 0.63?±?0.08 |
Table 5 SDAS of α(Al) dendrites, area fraction (%) of Al3Mg2 and Mn-rich phase in the T4-treated Al-5.0 Mg-0.6Mn-0.25Ce alloys produced at different cooling rates
Thickness (mm) | Rc (K/s) | SDAS (μm) | Area fraction (%) | |
---|---|---|---|---|
α(Al) dendrites | Al3Mg2 phase | Mn-rich phase | ||
50 | 0.22 | 100.8?±?15.2 | ~?0 | 1.43?±?0.16 |
25 | 0.33 | 79.7?±?12.4 | ~?0 | 1.38?±?0.13 |
10 | 1.39 | 50.8?±?9.4 | ~?0 | 0.72?±?0.10 |
5 | 7.65 | 31.3?±?5.7 | ~?0 | 0.63?±?0.08 |
Fig. 10 TEM images for the T4-treated alloys fabricated at a cooling rate of 7.65 K/s; a, b TEM bright-field images showing dispersoids in matrix and at grain boundary (the insets in a and b show the SAED patterns from the dispersoid and Al matrix, respectively; c, d the EDS results of dispersoids in matrix and at grain boundary)
Fig. 15 Effect of the cooling rate on increment percentage of strength (YS and UTS) and elongation of alloys before and after T4 heat treatment, noting that the ‘increment percentage’ refers to the enhancement of properties compared to those of as-cast materials
Fig. 16 SEM micrographs of fractured tensile specimens from the as-cast Al-5.0Mg-0.6Mn-0.25Ce alloys at different cooling rates: a 0.22 K/s; b 0.33 K/s; c 1.39 K/s; d 7.65 K/s; e EDS results of particles on fracture surfaces
Fig. 17 SEM micrographs of fractured tensile specimens from the T4-treated Al-5.0Mg-0.6Mn-0.25Ce alloys at different cooling rates: a 0.22 K/s; b 0.33 K/s; c 1.39 K/s; d 7.65 K/s; e EDS results of particles on fracture surfaces
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