PSI - Issue 14

Neeta Paulose et al. / Procedia Structural Integrity 14 (2019) 649–655 Neeta Paulose etal. / Structural Integrity Procedia 00 (2018) 000–000

654

Effect of temperature on fracture strain of Cycle A and Cycle B is shown in Fig.6. Fracture strain of Cycle A is higher till 250°C but at 550°C fracture strain is high in cycle B. Ductility in as cast condition is lower than Cycle A and Cycle B at both room temperature and 550°C , as shown in Fig.7 & Fig.8 respectively. Ductility in all three conditions increased when the temperature increased from 25  C to 550  C (Fig.7 &Fig.8).

10 15 20 25 30 35 40 45

%

Fracture Strain

Cycle A Cycle B

0 5

0

100

200

300

400

500

600

Temperature ° C

Fig.6 Effect of temperature on fracture strain

0 10 20 30 40

As cast Cycle A Cycle B

% Elonagtion

Ductilty at RT

Fig.7 % Elongation of as cast, Cycle A and Cycle B at Room temperature

10 15 20 25 30 35 40

As cast Cycle A Cycle B

% Elongation

0 5

Ductility at 550C

Fig.8 % Elongation of as cast, Cycle A and Cycle B at 550  C

Ductility in as cast structure is less than both Cycle A and B, due to dendritic microstructure. Strain induced martensitic formation is high in water quenched specimen as reported by Guilherme Correa Soares etal. (2017) and A.Molinari et.al.(2008). Formation of strain induced martensite is lesser beyond 150  C and the hardening is due to austenite phase in Cycle B specimen. Strain induced martensite nucleates at certain amount of plastic strain in deformed specimens [A.Molinari et.al. 2008]. So the differences are observed only in UTS and not in Yield strength.