Study on Interface Temperature and Plastic Strain During Ultrasonic Consolidation Process and their Influence of on Bonding Strength

Monday, May 11, 2015: 11:30 AM
Room 201A (Long Beach Convention and Entertainment Center)
Mr. Song Zhang , Tsinghua University, Beijing, China
Prof. Hui Zhang , Tsinghua University, Beijing, China
Prof. Lili Zheng , Tsinghua University, Beijing, China
Ms. Xiaohua He , Tsinghua University, Beijing, China
Prof. Huiji Shi , Tsinghua University, Beijing, China
Prof. Zhigang Yang , Tsinghua University, Beijing, China
Ultrasonic consolidation (UC), also known as ultrasonic additive manufacturing (UAM), is a promising additive manufacturing process to make bulk material from metal foils. Composite metal matrix as well as embedded sensors could be achieved at quite low temperature. Recrystallization which is observed across the contact interface is the main reason for the bond formation. The occurrence of recrystallization indicates that temperature elevation and plastic deformation strain near the bonding interface are the key control parameters of bonding formation. Hence, much work has been done to study the reached local conditions near the contact interface and also their influence on the bonding quality.

A CAFE model is built by combining the thermal-mechanical coupled ANSYS model and the in-house built cellular automat model. Using the built model, the microstructure evolution near the contact interface is obtained, such as recrystallization fraction, mean grain diameter and mean dislocation density. A series of punch tests are designed and conducted for the UC made samples. The punch force and the displacement of the punch pin are collected during the punch tests and the highest value of punch force is used as the bonding strength for the tested sample.

By plotting each case on the temperature - plastic strain coordinate system using the obtained results, each case is represented by a point on the temperature - plastic strain coordinate system. At the same time, the microstructure observation results and the punch tests results are compared between different cases. It is found that points closed to each other have the bond strength level close each other. Increasing the applied load will increase the work hardening effect which will weaken the bond quality. Points on the temperature - plastic strain coordinate system with relatively higher temperature elevation and lower plastic deformation will have higher bond strength level.

See more of: Additive Manufacturing I
See more of: Additive Manufacturing