Issue 37

M. S. Raviraj et alii, Frattura ed Integrità Strutturale, 37 (2016) 360-368; DOI: 10.3221/IGF-ESIS.37.47

a 2      

2

3

4

   

a       W

a      

a      

a      

a      

W 0.886 4.64  











f

(2)

13.32

14.72

5.60

  

a           

W W

W W

   

1-

W 3/ 2 

B/W=0.2 B/W=0.3 B/W=0.4 B/W=0.5 B/W=0.6 B/W=0.7

AL+3wt%TiC a/W=0.5

12

10

8

6

Load,kN

4

2

0

-1 0 1 2 3 4 5 6 7 8 9 10 11

CMOD,mm

Figure 7 : Load vs. crack mouth opening displacement curves for Al6061+wt3% TiC composite of various B/W ratios.

6

Al+5%TiC a/W=0.5

5

B/W 0.2 B/W 0.3 B/W 0.4 B/W 0.5 B/W 0.6 B/W 0.7

4

3

Load,kN

2

1

0

0

2

4

6

8

10

CMOD,mm

Figure 8 : Load vs. crack mouth opening displacement curves for Al6061+wt5% TiC composite of various B/W ratios. The calculated K Q is plotted against various B / W ratios for various Al6061-TiC composites. Fig. 10 shows the variation of K Q vs. B / W ratios for various Al6061-TiC composites. It is observed from Fig.10 that the K Q decreases with increase in B / W ratios and found to remain constant for B / W ≥0.5. This constant value of K Q for B / W ≥0.5 prevail the plane strain fracture toughness (K IC ) of the composite. For B / W ≤0.4, the value of K 1C can be considered the real plane stress fracture toughness. It is analyzed from Fig. 10 that the increase of TiC from 3wt% to 5wt% in Al6061 matrix composites, there will be a decrease in fracture toughness from 19.2 MPa√m to 16.4 MPa√m and further increase of TiC to 7wt% the

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