1988-10-01

Fracture Mechanics Characteristics of Laser-Welded Aluminum-Lithium Sheet Joints 881405

Because of its low density and improved elastic modulus properties, use of aluminum-lithium alloys has good potential for substantial weight savings in aircraft, spacecraft, and missile applications. To study further the possible uses of this material, Douglas Aircraft Company conducted a program to investigate the effects of welding methods on the load-carrying capacities of welded joints made of aluminum-lithium alloy.
In the study, laser-welded 2091-T8X aluminum-lithium sheet joints were fabricated and tested. The high-energy intensity and low-heat input generated by laser welding sharply narrowed the heat-affected zone and markedly improved the strength of the weld. Fracture toughness, Jlc, was determined by the J-integral procedure of ASTM E813. The fatigue crack growth rate, da/dN, was measured with precracked specimens and correlated by ΔK. The fracture toughness and fatigue crack growth in the welding zone and in the base metal section were compared. The crack and fracture morphology exhibited by tested specimens was investigated with a scanning electron microscope. Metallurgical factors and residual stresses at the crack tip area were analyzed by computer controlled X-ray diffraction techniques.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Joining Aluminum to Stainless Steel for Space Vehicle Applications

650754

View Details

TECHNICAL PAPER

Thermal Fatigue of Turbine Alloys with Special Reference to PWA 663 Nickel-Base Alloy

660056

View Details

TECHNICAL PAPER

Advanced Aluminum and Aluminum-Lithium Solutions for Derivative and Next Generation Aerospace Structures

2012-01-1874

View Details

X