Effect of friction stir weld defects on fatigue lifetime of an Al-Cu-Li alloy

Thomas Le Jolu (1) , Thilo F. Morgeneyer (1) , Anne-Françoise Gourgues-Lorenzon (1)

1 CDM - Centre des Matériaux

The effect of Joint Line Remnant (JLR) on the fatigue lifetime of friction stir welds of a 2198Al-alloy in T851 condition has been assessed experimentally by investigating "JLR-free"welds (welded in one sheet) and "JLR-bearing" welds (produced by welding 2 sheets with anatural oxide layer). A strong decrease in Microhardness is found for the weakest weld zonetogether with a reduction in tensile properties compared to the base material, namely, 45% inyield strength and 22% in ultimate tensile strength. The fatigue strength of JLR-free and JLRbearingwelds at 105 cycles (R=0.1) is reduced by 10% and 15% respectively compared tothe base material. No obvious effect of JLR was evidenced concerning crack initiationmechanisms.

Mots clés: Friction stir welding; joint line remnant; Al-Cu-Li; S-N curves

Domaines: Matériaux

Thomas Le Jolu, Thilo F. Morgeneyer, Anne-Françoise Gourgues-Lorenzon. Effect of friction stir weld defects on fatigue lifetime of an Al-Cu-Li alloy. Fracture of materials and structures from micro to macro scale - ECF 18, Aug 2010, Dresden, Germany. 8 p. ⟨hal-00541248⟩