Crack Paths 2006

B M

H A Z

P a )

F Z

s s ( M

s t r e

0.0

2.0

4.0

6.0

8.0

10.0

strain (%)

12300

Figure 1. Yield curves of Al6056 T78 L B W

Fracture Toughness

Fracture resistance is characterised by CTOD,G5, vs. crack extension, 'a, see Schwalbe

et al. [2]. Tests of laser beam welded Al6056 have been carried out using compact

tension specimens (C(T)-specimen, W=50mm, a/W=0.5, B=4.2 mm). A sketch of the

specimen is provided in Figure 2. The specimens were statically loaded perpendicular to

the rolling direction. The initial crack was introduced in the B M(Figure 2a), in the

middle of the FZ (Figure 2b) and within the H A Z(Figure 2c). Due to the undermatch

configuration, for configuration (b) the crack extends in the FZ.

62,5

B M

B M

50,0

a

0

H A Z

2 , 5

3 7 , 5

H A Z

FZ

FZ

1 2 , 5

a) initial crack in B M

c) initial crack in the H A Z

b) initial crack in the middle

of the FZ

Figure 2. Initial crack configurations investigated, measures in m m