PSI - Issue 14

Amit Singh et al. / Procedia Structural Integrity 14 (2019) 78–88

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Amit Singh et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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were used to supplement the aforementioned observations. From Table 4, it can be seen that n and n 3 increases with decreasing the ST temperature from β transus temperature. This shows a good agreement with the above mentioned results of strain hardening rate (Fig. 3 b) and degree of strain hardening (σ UTS /σ 0.2% ) (Table 2). Hence, the increase in strain hardening exponent can be attributed to the decrease in lamellae and colony size i.e., reduced slip length with decreasing solution treatment temperature i.e. with increasing α p phase from 0.045% to 22% α p .

Table 3. The R 2 values of flow stress behavior Samples [ST + aged (973 K/2Hrs)]

Hollomon

Ludwik 0.94199 0.98064 0.97512 0.89416

Voce

Swift

Ludwigson

ST (1288 K) ST (1303 K) ST (1318 K) ST (1333 K)

0.99182 0.98736 0.99214 0.97238

0.97345 0.97428 0.97565 0.99406

0.99899 0.98971 0.99242 0.99529

0.99989 0.99746 0.99743 0.99865

Fig. 4. The modified Crussard – Jaoul (C-J) model for strain hardening behavior of IMI 834 alloys solution treated at (a) 1288 K, (b) 1303 K, (c) 1318 K and (d) 1333 K for 2Hrs. followed by aging at 973 K/ 2Hrs. followed by air cooling.