Heat generation and deformation in ultrasonic welding of magnesium alloy AZ31

• Published in: Journal of materials processing technology Vol. 272; no. C; pp. 125 - 136
• Main Authors: Huang, Hui, Chen, Jian, Lim, Yong Chae, Hu, Xiaohua, Cheng, Jiahao, Feng, Zhili, Sun, Xin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2019; Elsevier BV; Elsevier
• Subjects: Amplitudes; Coefficient of friction; Deformation mechanisms; Finite element method; Friction; Heat; Heat generation; High speed cameras; Indentation; Infrared cameras; Magnesium alloys; Magnesium base alloys; MATERIALS SCIENCE; Metal sheets; Numerical model; Temperature distribution; Ultrasonic welding; Vibration analysis; Vibration measurement; Ultrasonic welding; Heat generation; Friction; Indentation; Numerical model
• ISSN: 0924-0136; 1873-4774
• DOI: 10.1016/j.jmatprotec.2019.05.016

•Temperature at the faying interface of AZ31 ultrasonic weld (USW) was measured in situ.•A 2D thermo-mechanical FEA model was developed to simulate ultrasonic welding.•The heat generation mechanism was clarified by relative motions at different interfaces.•The predicted temperature history and profile compare well with infrared measurement.•Larger vibration amplitude (≥8μm) is favorable in ultrasonic welding of AZ31 sheets. A dual-sonotrode edge welding setup and a finite element analysis (FEA) model were developed for ultrasonic welding (USW) of AZ31 magnesium alloy sheets. Sonotrode vibration was measured quantitatively by a high-speed camera and introduced into the model as the driving force. The transient temperature field on the edge of the sheets was captured by an infrared camera. The heat generation mechanism in USW was investigated by a parametric study on the friction coefficient. Friction at faying interface should be smaller than those at other interfaces to enhance heat generation. The model was then validated by the experimental thermal history at the faying interface and the full temperature field as well as sonotrode indentation. Using the established model, USW under different welding powers (or vibration amplitudes) but at the same energy input was analyzed to characterize USW bond condition. Much higher temperature in the weld was observed with increasing vibration amplitudes, while reasonable indentation was maintained. Vibration amplitude other than energy input was a critical factor in bond formation between AZ31 sheets.