Fatigue and fracture toughness characteristics of laser rapid manufactured Inconel 625 structures

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 527; no. 29; pp. 7490 - 7497
• Main Authors: Ganesh, P., Kaul, R., Paul, C.P., Tiwari, Pragya, Rai, S.K., Prasad, R.C., Kukreja, L.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.11.2010; Elsevier
• Subjects: Applied sciences; Crack propagation; Exact sciences and technology; Fatigue crack growth; Fatigue failure; Fractography; Fracture mechanics; Fracture toughness; Fractures; Inconel 625; J integral; J-integral test; Laser rapid manufacturing; Lasers; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nickel base alloys; Slopes; Superalloys; Transgranular fracture; Fatigue crack growth; Transgranular fracture; Inconel 625; Laser rapid manufacturing; J-integral test; Fractography; J integral; Laser deposition; Wrought alloy; Experimental device; Fatigue fracture; X ray diffraction; Fatigue crack; Crack propagation; Fracture toughness; Rapid prototyping
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2010.08.034

▶ Mechanical test results of Laser rapid manufactured (LRM) Inconel 625 are reported. ▶ 12 and 25 mm thick CT specimens of LRM Inconel 625 showed similar fatigue crack growth. ▶ Stage II crack growth behavior is observed in the investigated Δ K range. ▶ Fracture toughness testing by J-integral method yielded J 1c of about 200-250 kJ/m 2. Fatigue crack growth and fracture toughness characteristics of laser rapid manufactured (LRMed) Inconel 625 compact tension specimens of thickness 12 and 25 mm were investigated. Fatigue crack propagation in all the specimens investigated in the stress intensity range (Δ K) of 14–38 MPa√m, exhibited stage II crack growth in Paris’ regime with nearly same slopes of crack growth per cycle versus Δ K plot. Fatigue crack growth rates in the LRMed specimens of present study were found to be lower than the reported values for wrought Inconel 625 in the Δ K range of 14–24 MPa√m and above this range they tended to coincide. X-ray diffraction patterns of the fractured surfaces revealed that the crack propagated along the growth direction of the specimens which was predominantly along the (1 1 1) plane. The fracture toughness values ( J 0.2) for LRMed Inconel 625 specimens were found to be in the range of about 200–255 kJ/m 2. The LRMed specimens exhibited stable crack growth during the J-integral test.