Effects of Welding Heat Input on CO2 Laser Weldability of AZ31B and AZ61A Magnesium Alloy Extrusion Sheet
| Autor: | Chang-lin Lee, 李長凌 |
|---|---|
| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 Effects of welding heat input on CO2 laser weldability of AZ31B and AZ61A magnesium alloy extrusion sheet which has been investigated. CO2 laser beam welding was conducted on AZ31B and AZ61A magnesium alloy sheets at different welding speeds and input density. The depth-to-width ratio, mechanical property, microstructure, chemical component, and fractography, of the welds were evaluated using optical microscopy, tensile tests, hardness tests, energy dispersive X-ray spectroscopy, and electron probe for microanalysis, scanning electron microscope, and compared with TIG(tungsten inert gas) welding. Results indicated that both the hardness and tensile strength of laser beam welding were higher than those of TIG welds. It was shown that both the volume of precipitates increased on welded metal while the increase of heat input, AZ61A got more precipitates than AZ31B. But welded metal lose of alloy element increased on increase of heat input. Liquation Crack and segregation of Al and Zn were found on the edge of laser welded bead of AZ61A, but not found in TIG welded bead or in AZ31B. Liquation Crack led to different tensile fractography on two alloys. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|