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Liquation Cracking Susceptibility and Mechanical Properties of 7075 Aluminum Alloy GTAW Joints
Zhuoxin Li1, Yulin Zhang1, Hong Li1
1Institute of Light Alloy and Processing, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China.
Abstract:
In this work, aluminum alloy 7075-T651 was welded by using customized Al-Cu-Si and Al-Cu-Mg-Zn filler wire during gas tungsten arc welding. The liquation cracking susceptibility of the joints was tested under a circular-patch welding experiment. Besides, the temperature vs. solid fraction curves (T-fS) was calculated for different samples to reveal the formation mechanism of liquation cracking. The joint was susceptible to liquation cracking if (fS)weld > (fS)workpiece during the cooling stage. The results of the circular-patch welding experiment show that the liquation cracking susceptibility of the joint by using ER5356, Al-Cu1.5-Si4.5, Al-Cu3.0-Si2.5, Al-Cu4.5-Si1.5, Al-Cu2.3-Mg2.3-Zn6.6 and Al-Cu2.2-Mg2.0-Zn7.8 filler metal is 22.8%, 8.3%, 2.8%, 2.8%, 3.3% and 1.4%, respectively. The mechanical test shows that the data dispersion of the 7075 gas tungsten arc welding joint can be decreased by eliminating the liquation crack.
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