PSI - Issue 7

Ludvík Kunz et al. / Procedia Structural Integrity 7 (2017) 44–49 Ludvík Kunz / Structural Integrity Procedia 00 ( 201 7) 000–000

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3

870 °C for 24 h with cooling on air. The obtained structure, similarly like in Fig. 2(a) with marked grain boundaries, is shown in Fig. 2(b). The average grain size was larger than in IN 713 LC, namely of about 2.5 mm. The IN 713LC contained casting defects. An example is shown in Fig. 2(c). The maximum size of isolated defects was 0.1 mm, however, they formed often clusters. The HIP procedure applied to the MAR-M 247 resulted in the material without significant casting defects, Fig. 2(d). The chemical composition of both the alloys is given in Tab. 1.

Table 1. The chemical composition of (a) IN 713LC and (b) MAR-M 247 in wt. % or ppm. (a) C Cr Mo Al Ti Ta Nb B Zr

Co

Mn 0.03

Si

Fe

Cu

0.06

12.40

4.11

5.52

0.66

<0.02

2.27

0.01

0.08

0.01

0.08

0.19

0.01

P

S

Ni

<0,001 <0,001

bal.

(b)

C

Cr

Mo 0.74

Al

Ti

Ta

Nb

W

Co

B

Hf

Zr

Mn

Si

0.15

8.50

5.50

1.02

3.01

0.05

9.85

9.77

0.015

1.31

0.037

<0.01

0.02

Fe

Cu

P

S

N

O

Pb

Ag

Mg 6.2 ppm

Ga

Se

Ni

< 10 ppm

< 10 ppm

< 10 ppm

< 10 ppm

< 0.5 ppm

1.4 ppm

14 ppm

< 1 ppm

0.11

0.01

bal.

b

a

a

d

c

b

Fig. 2. Coarse dendritic structure of (a) IN 713LC; (b) MAR-M 247. Porosity of alloys: (c) casting defects in IN 713LC; (d) defect free structure of MAR-M 247 after hot isostatic pressing.

Fig. 1. Specimens for creep/fatigue tests. (a) two flow shell mold for 10 rods; (b) dimensions of specimens.