Laser and electron beam treatments for corrosion protection of friction stir welds in aerospace alloys

Friction Stir Welding (FSW) is a suitable technology for aerospace structure development and is a possible replacement for mechanical fastening. To achieve the application of FSW, pre and post-weld treatments are required. A pre-weld treatment of surface preparation was required to ensure a weld with good mechanical properties. The surface preparation necessary is the removal of paint and anodising layers from aerospace alloys. Laser paint removal was assessed and designed to remove these layers with only an oxide remaining, which welded to produce high quality welds. The post-weld treatment was essential to increase the corrosion resistance of the welded area. The improvement in corrosion resistance was achieved with High Power Beam Surface Modification (HPBSM), which created a homogeneous surface through rapid surface melting and solidification. The rapid thermal processing dissolved and dispersed the precipitate solute atoms which were retained in solid solution through planar solidification. Electron beams and various lasers were used in the HPBSM processing. Excimer Laser Surface Melting (LSM) improved corrosion resistance but the layer depth was restricted by processing parameters. HPBSM processing studies using an electron beam, USP-CO₂ laser and Nd:YAG laser provided understanding on how processing parameters controlled the modified layer characteristics.

Name dc:type.qualificationname

d_en

Level dc:type.qualificationlevel

d_en

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2010

Author dc:creator

• Siggs, Eirian Bethany

• TS Manufactures
• TN Mining engineering. Metallurgy