6005铝合金搭接接头组织及疲劳性能研究

白易山; 杨尚磊; 朱敏琪; 范聪

6005铝合金搭接接头组织及疲劳性能研究

白易山^a,,
杨尚磊^{a, b, ,},
朱敏琪^a,
范聪^a

a.
上海工程技术大学材料工程学院
b.
上海市激光先进制造技术协同创新中心，上海 201620

基金项目: 国家自然科学基金资助项目（51971129）；上海市自然科学基金资助项目（19ZR1421200）

详细信息

作者简介:
白易山（1997−），男，在读硕士，研究方向为铝合金的疲劳可靠性. E-mail：baiyishan1997@163.com

通讯作者:
杨尚磊（1968−），男，教授，博士，研究方向为材料/接头/结构的疲劳可靠性. E-mail：yslei@126.com

中图分类号: TU 395
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- 被引次数: 0
出版历程
- 收稿日期: 2020-09-25
- 刊出日期: 2021-03-30

Study on Microstructure and Fatigue Properties of 6005 Aluminum Alloy Lap Joint

BAI Yishan^a
,,
YANG Shanglei^{a, b
, ,},
ZHU Minqi^a,
FAN Cong^a

a.
School of Materials Engineering
b.
Shanghai Collaborative Innovation Center for Laser Advanced Manufacturing Technology, Shanghai University of Engineering Science, Shanghai 201620, China

摘要

摘要: 采用熔化极惰性气体保护（MIG）焊对6005铝合金进行搭接焊接试验. 对焊接接头进行微观组织观察和显微硬度测试，结果显示，熔合区出现联生结晶特点，焊缝中心以等轴晶为主，热影响区（HAZ）晶粒发生严重粗化，焊缝区的维氏硬度（HV）为64.5，母材区为89.6，接头出现明显软化区. 在疲劳性能测试中焊接接头疲劳强度只有母材的21.41%，焊接接头疲劳断口呈韧性断裂和解理断裂的混合性断裂. 分析疲劳裂纹扩展机理得出，在裂纹尖端钝化和加载应力循环下，裂纹沿45°方向呈“Z”字型扩展.
- 6005铝合金 /
- 微观组织 /
- 疲劳性能 /
- 裂纹扩展
Abstract: Metal inert-gas (MIG) welding was used to conduct lap welding experiments on 6005 aluminum alloy. The microstructure and microhardness of the welded joint were observed. The results show that the intergrowth crystal appears in the fusion zone, the equiaxed crystal is dominant in the weld center, and the grain coarsening has occurred in the heat affected zone (HAZ). The Vickers hardness (HV) of the weld zone is 64.5, and that of the base metal zone is 89.6, and the joint appears obvious softening zone. The fatigue strength of the welded joint is only 21.41% of the base material in the fatigue performance test, and the fatigue fracture of the welded joint is a mixed fracture of ductile fracture and dissociative fracture. By analyzing the mechanism of fatigue crack propagation, it is concluded that the crack propagates in a “Z” shape along the 45° direction under the condition of crack tip passivation and loading stress cycle.
- 6005 aluminum alloy /
- microstructure /
- fatigue properties /
- crack growth

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图 1 疲劳试样

Figure 1. Fatigue specimen

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图 2 6005铝合金MIG焊接接头微观组织

Figure 2. Microstructure of 6005 aluminum alloy MIG welded joint

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图 3 焊接接头显微硬度曲线分布图

Figure 3. Microhardness distribution curves of welded joints

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图 4 母材和焊接接头的S-N曲线图

Figure 4. S-N curves of base metal and welded joint

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图 5 焊趾处断裂的宏观形貌图

Figure 5. Macroscopic morphology of fracture at weld toe

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图 6 疲劳断口形貌的SEM图

Figure 6. SEM images of fatigue fracture morphology

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图 7 疲劳裂纹

Figure 7. Fatigue crack

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图 8 Z字传播模型

Figure 8. Z-character propagation model

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表 1 6005铝合金和ER5356焊丝的化学成分

Table 1. Chemical composition of 6005 aluminum alloy and ER5356 welding wire %

材料 Fe Cu Si Mn Mg Cr Zn Ti Al

6005 0.35 0.30 0.60 0.50 0.40 0.30 0.20 0.10 余量
ER5356 0.40 0.10 0.25 0.35 4.80 0.15 0.10 0.13 余量

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表 2 焊接工艺参数

Table 2. Welding process parameters

焊接电流 / A 焊接电压 / V 焊接速度 / （mm·s⁻¹）气体流速 / （L·min⁻¹）

160 21 5.0 20

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参考文献(12)

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