Effect of Rare Earths on Mechanical Properties of A Cast Zinc-Aluminum-Copper Alloy
Abstract:
The strength of zinc-base alloys with various compositions of Al and Cu were studied.By adding Ti, B, RE and Mg, a high-strength zinc-base alloy (Al14%, Cu10%) was obtained.On the base of ZnAl14Cu10, the effect of various amounts of rare earths (0, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%) on the properties of zinc-base alloy was studied.Water cooling and air cooling were applied on the alloys.The results showed that ZnAl alloy with 0.4%RE is the optimal alloy for molds with the method of water cooling.
Fig.8 Microstructures of sample 10# (ZnAl14Cu10) (a) Air cooling; (b) Water cooling
图9 14#试样 (ZnAl14Cu10RE0.4) 显微组织
Fig.9 Microstructures of sample 14# (ZnAl14Cu10RE0.4) (a) Air cooling; (b) Water cooling
图10 15#试样 (ZnAl14Cu10RE0.6) 显微组织
Fig.10 Microstructures of sample 15# (ZnAl14Cu10RE0.6) (a) Air cooling; (b) Water cooling
图11 ZnAl14Cu10RE0.4水冷合金的SEM图
Fig.11 SEM microstructure of ZnAl14Cu10RE0.4
表4 ZnAl14Cu10RE0.4合金的能谱分析/ (%, 质量分数)
Table 4 Energy spectrum analysis of ZnAl14Cu10RE0.4
Position
Al
Cu
Ce
La
Ce
A
6.34
15.90
0.04
0.06
77.76
B
24.20
11.39
0
0.07
64.41
C
55.31
5.18
0.03
0.11
39.51
D
6.51
11.31
0.02
0.08
74.19
E
21.73
10.93
0
0.38
66.96
F
12.61
12.70
0
0.09
74.19
G
53.23
8.21
0
0
38.56
表5 各种锌合金的机械性能 (25 ℃)
Table 5 Mechanical properties of various Zn alloys (25 ℃)
Alloy
σb/MPa
δ/%
HB
Zn-4Al-3Cu (China)
240~300
2.5
120~130
ZnA27Cu2Mg (China)
400~440
1.0~2.0
110~130
ZnA12 (America)
310~350
1~3
105~120
Zn-12Al-1.5Cu (Japan)
280~320
1~3
90~110
Zn-11Al-0.75Cu (Canada)
350~385
1~3
105~125
ZnA14Cu10RE0.4 (This paper)
492.6
1.42
168
表6 各种锌合金高温机械性能 (200 ℃)
Table 6 Mechanical properties of various Zn alloys (200 ℃)
Alloy
σb/MPa
δ/%
ZnAl8Cu3
120~140
24
ZnA14Cu10RE0.4 (This paper)
216
26
3 结 论
1. 在ZnAl14Cu10合金中加入微量稀土元素使合金的机械性能显著提高, 尤其是当稀土含量增加到0.4%时, 并采取水冷方式的综合性能较佳, 其成分为: Al 14%, Cu 10%, RE 0.4%, Mg 0.03%, Ti 0.15%, B 0.03%, 其余为Zn, 但当稀土含量进一步提高后, 合金机械性能明显下降。