Crystalline phases and granular structure of TIG-welded Zn–22Al–2Cu alloy plates

✍ Scribed by Jaime Hinojosa-Torres; Sergio M. Durán-Guerrero; Juan M. Aceves-Hernández; Víctor M. Castaño-Meneses

• Book ID: 104023794
• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 838 KB
• Volume: 198
• Category: Article
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2007.06.073

✦ Synopsis

Rolled plates of the Zn-22Al-2Cu (weight %) alloy were welded by the Tungsten-Inert-Gas (TIG) welding process; this process had not been applied before to materials of this alloy.

The welding conditions were experimentally determined. X-ray diffraction reveals that the crystalline phases Á S , Á T , ˛ S , ˛ T are present in the parent metal and in the fusion zone. The phase (CuZn 4 ) is present in the fusion zone and the phase (Al 4 Cu 3 Zn) is present in the parent metal. Inside the fusion zone, a dendritic structure surrounded by a network was observed. From chemical analysis, it is found that the ˛ S , Á T and phases constitute the body of the dendrite and that the Á S and phases compose the surrounding network. Near the fusion line, in the grain growth zone, equiaxed grains surrounded by a network were observed. Beyond the grain growth zone the grain shape evolved from equiaxed to elongated.

Finally, a penetration value of 2.8 mm was attained when an electrical current of 80 A was used and, with this penetration, the heat affected zone (HAZ) extended up to approximately 0.8 times the penetration value.