Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 13 No. 2 April 2003|
（State Key Laboratory of Advanced Welding Production Technology,
School of Material Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China）
Abstract:The restraint effects of pulse frequency and pulse duty cycle on the precipitates of harmful needle like Al4C3 phase were studied in CO2 impulsed laser welding through the experiment on the SiCp/6063 composite, and the microstructures of the weld under the different process parameters (pulse time from 1ms to 20ms,duty cycle from 50% to 91%) were analyzed. In order to compare, CO2 continuous laser was conducted under the same efficiency. The results demonstrate that the proper laser pulse frequency and duty cycle can restrain the formation of Al4C3 effectively. However, the burning loss of SiC is more serious and the fluidity of molten pool is less in continuous laser welding than in impulsed laser welding.
Key words: laser beam welding; microstructure; aluminum metal matrix composites