Fig. 8. A solidification map to avoid primary β is shown.
避免初生β相出现的凝固图
the remaining liquid is enriched in copper (and other solute elements). Macrosegregation of this sort also can develop in Al-Si
casting alloys, but it is more difficult to see this in casting X-rays. (Te density difference between aluminum and sili- con is much smaller than between aluminum and copper.)
Calculating Solidification Paths
Equations for microsegregation during solidification can be used to calculate solidification paths for casting alloys. Te easiest way to proceed is to assume the distribu-
tion coefficients for the binary alloy systems can be used in ternary alloy systems. Te starting point for our calculations is the aluminum rich corner of the Al-Si-Fe ternary. Eleven different intermetallic compounds have been identified in this system. Four of them occur in the aluminum-rich por- tion of the ternary presented in Fig. 5. Tey are: • FeAl3, which is found in the Al-Fe binary and in alloys low in silicon.
• δ-FeSiAl, which has the composition FeSi2Al3. Te compound which is of most concern here is the β
凝固路径计算 凝固过程的偏析方程可以用于铸造合金凝固路径的 计算。
最简单的处理方法是假设二元合金系的分配系数可 以在三元合金系中使用。我们计算的起始点是Al-Si- Fe三元系的富铝角。在该体系中，已经确定的不同金 属间化合物有11种，其中4种出现在三元系的富铝部 分如图5所示。它们分别是： • FeAl3，出现在Al-Fe二元系合金低硅区域。 • α-FeSiAl，其成分接近Fe2SiAl8。 • β-FeSiAl，通常用FeSiAl5的成分代表。 • δ-FeSiAl，具有FeSi2Al3的成分。
• α-FeSiAl, which has a composition close to Fe2SiAl8. • β-FeSiAl, which is usually represented by the composition FeSiAl5.
phase. Tis is the intermetallic compound normally observed in commercial castings. Te calculated solidification paths for an AA309 alloy having 5% silicon and various iron contents have been calcu- lated. (Tis alloy also has 1.2% copper and 0.5% magnesium, but this is ignored in the calculation.) To simplify presenta-
上列所述最令人关注的化合物是β相。商业铸件中 通常都能发现这种金属间化合物。
含有5％的硅和不同的铁含量的AA309合金的凝固 路径已计算出来。（该合金还含有1.2％的铜和0.5％ 的镁，但在计算中被忽略。）为了简单地呈现计算结 果，这里仅显示了相界部分。此外，详细部分见可从 图5看出。图6所示为合金铁含量0.3和0.6％的结果， 分别给出了两条偏析曲线，较低的（红色）曲线所 示凝固时间为10秒；较高的（蓝色曲线）所示是是
Fig. 9. The plot shows the proper- ties of heat treated (T6) castings for seven different alloy composi- tions: (1) 4.5Si-1Cu-0Mg-0.2Fe; (2) 4.5Si-1Cu-0.1Mg-0.5Fe-0.25Mn; (3) 9Si-1Cu-0.1Mg-0.5Fe-0.25Mn; (4) 4.5Si-4Cu-0.1Mg-0.2Fe; (5) 9Si-4Cu-0.1Mg-0.2Fe (6) 4.5Si- 4Cu-0.1Mg-0.5Fe-0.25Mn; (7) 9Si-4Cu-0.1Mg-0.5Fe-0.25Mn.
七种不同合金成分合金经T6热 处理后的性能
September 2014
FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION | 57
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82