Abstract
Pulsed Nd:YAG laser beam welding (P-LBW) and pulsed tungsten inert gas (P-TIG) welding were used to prepare full penetration bead-on-plate weldments of 1.6 mm thick Ti-5Al-2.5Sn alpha titanium alloy sheet. The influence of welding phenomenon on the microstructure, micro-hardness, tensile properties, surface and sub-surface residual stress distribution and deformation and distortion of both the weldments were studied. Higher cooling rate in P-LBW resulted in complete α’ martensitic transformation in fusion zone whereas in P-TIG weldment α’ and acicular α was formed within equiaxed β matrix due to lower cooling rate. Hardness in fusion zone of P-LBW was higher than that of the fusion zone of P-TIG weldment due to faster cooling rate in P-LBW. The welded zone in both the weldments showed higher hardness and strength than that of the parent metal since a ductile fracture occurred in the un-welded section during tensile testing. Residual stresses in both P-LBW and P-TIG weldments showed similar trend but the distribution was much narrower in P-LBW due to less width of heat affected zone. P-LBW resulted in more nonuniformity in through thickness stress profile because of greater top to bottom width ratio. Less residual stresses, deformation and distortion and superior mechanical properties in P-LBW made the process more feasible than P-TIG for the welding of Ti-5Al-2.5Sn alloy sheet.
Original language | English |
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Pages (from-to) | 24-38 |
Number of pages | 15 |
Journal | Journal of Materials Processing Technology |
Volume | 242 |
DOIs | |
Publication status | Published - 1 Apr 2017 |
Funding
The authors would like to thank Ghulam Ishaq Khan Institute of Engineering Sciences and Technology (GIKI) for providing financial assistance and Pakistan Welding Institute (PWI) and Pakistan Institute of Engineering and Applied Sciences (PIEAS) for use of facilities.
Keywords
- deformation
- hole-drill method
- pulsed laser welding
- pulsed TIG welding
- residual stresses
- titanium alloy
- comparative study