An evaluation of CO[sub 2] laser beam welding on a Ti[sub 3]Al-Nb alloy

Journal Article · Wed Feb 01 00:00:00 EST 1995 · Welding Journal (Miami); (United States)

OSTI ID:6610089

Martin, G S ^[1]; Albright, C E ^[2]; Jones, T A ^[3]

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1. General Electric Corp., Cincinnati, OH (United States)
2. Ohio State Univ., Columbus, OH (United States). Dept. of Welding Engineering
3. Ford Motor Co., Dearborn, MI (United States)

The CO[sub 2] laser beam weldability of Ti-14.3 wt-% Al-21 wt-% Nb, a Ti[sub 3]Al-Nb alloy, was investigated. A sequence of pulsed and continuous wave (CW) CO[sub 2] laser beam welds was made on 1.7-mm (0.067-in.) thick coupons of Ti-1421. The weld cross-sections were subjected to microhardness evaluation and characterized by optical metallography. The hardness values were plotted with respect to calculated cooling rates to reveal possible trends in microhardness. Laser welds were produced without cracks, porosity or other discontinuities. Laser welding with calculated cooling rates between 195 and 10,400 C/s produced relatively constant microhardness values. These values ranged between 373 and 432 DPH for the heat-affected zone (HAZ), and between 364 and 416 for the fusion zone (FZ). These results are in contrast to Mascorella's results for gas tungsten arc welding, which showed microhardness values have an increasing trend with increased cooling rate (from 297 to 488 HAZ and from 292 to 459 FZ for cooling rates from 2 to 50 C/s). Bend ductility values within the unaffected base metal (UBM) range were obtained in full penetration longitudinal bend specimens for laser welds with calculated cooling rates above 3,400 C/s. For cooling rates of 1,380 C/s and lower ductilities were well below the UBM range. The slower cooled welds exhibited a larger flat cleavage fracture area and lower ductility than the rapidly cooled welds. The results of this investigation show that careful selection of CO[sub 2] laser welding conditions will result in cooling rates that will yield more ductile HAZs and FZs when compared to gas tungsten arc welding (GTAW).

• OSTI ID: 6610089
• Journal Information: Welding Journal (Miami); (United States), Vol. 74:2; ISSN 0043-2296
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
33 ADVANCED PROPULSION SYSTEMS
ALUMINIUM ALLOYS
LASER WELDING
MECHANICAL PROPERTIES
GAS TURBINE ENGINES
HEAT RESISTANT MATERIALS
NIOBIUM ALLOYS
TITANIUM BASE ALLOYS
WELDED JOINTS
HEAT AFFECTED ZONE
TERNARY ALLOY SYSTEMS
ALLOY SYSTEMS
ALLOYS
ENGINES
FABRICATION
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
JOINING
JOINTS
MATERIALS
TITANIUM ALLOYS
WELDING
ZONES
360101* - Metals & Alloys- Preparation & Fabrication
360103 - Metals & Alloys- Mechanical Properties
330103 - Internal Combustion Engines- Turbine