Study on softening behavior of laser welded joint in GH909 alloy

다국어 초록 (Multilingual Abstract)

Laser beam welding was conducted on GH909 alloy in a solution treatment and aging conditions. The microstructure, mechanical properties, and softening behavior of welded joints were carefully studied using scanning electron microscopy, energy diffraction spectroscopy, and other techniques. Results indicated that γ′-Ni 3 (TiAl)-precipitated phases were produced inside the matrix, and the presence of Laves at grain boundaries restricted grain growth. A sharp reduction in γ′-precipitated phases evidently weakened the average tensile strength and microhardness of the welded joints. Moreover, fractures occurred in the weld zone. Microcracks in the fracture of the joint mainly depended on the competition result between thermal stress and cohesion forces among the grains.

참고문헌 (Reference)

1 Y. Yan, "The mechanism of precipitation strengthening in Fe-Ni austenitic alloy electron beam weldment" 630 : 85-89, 2015

2 S. Yaru, "Oxidation behavior of modified low thermal expansion thermo-span superalloy at 650 degrees C" 41 : 361-364, 2012

3 S. Q. Guo, "Numerical simulation of solidification and liquation behavior during welding of lowexpansion superalloys" 5 (5): 146-159, 2011

4 X. Dong, "Microstructure of carbides at grain boundaries in nickel based superalloys" 28 (28): 1031-1038, 2012

5 M. A. Balachander, "Microstructure characterisation of Solution treated (ST) and Solution treated and aged (STA) Incoloy 909" 27 (27): 805-810, 2011

6 M. A. Balachander, "Microstructure characterisation of Solution treated (ST) and Solution treated and aged (STA) Incoloy 909" 27 : 805-810, 2011

7 T. Liu, "Microstructure and mechanical properties of laser-arc hybrid welding joint of GH909 alloy" 80 : 56-66, 2016

8 F. Caiazzo, "Investigation on edge joints of Inconel 625 sheets processed with laser welding" 93 : 180-186, 2017

9 Y. Sun, "Influence of phosphorus on oxidation behavior of low thermal expansion superalloy IN909 at 650 °C" 16 (16): 1958-1961, 2014

10 F. Torster, "Influence of grain size and heat treatment on the microstructure and mechanical properties of the nickel-base superalloy U 720 LI" 234 (234): 189-192, 1997

11 R. Damodaram, "Hot tensile and stress rupture behavior of friction welded alloy 718 in different pre-and post-weld heat treatment conditions" 612 : 414-422, 2014

12 L. Ma, "Effects of different metallurgical processing on microstructures and mechanical properties of inconel alloy 783" 13 (13): 32-38, 2004

13 J. F. Zhang, "Effect of solid solution treatment on microstructure of Fe-Ni based high strength low thermal expansion alloy" 15 (15): 75-78, 2008

14 O. Covarrubias, "Effect of heat treatment on mechanical properties of alloy 909" 27 : 1092-1097, 2011

15 O. Covarrubias, "Effect of heat treatment on mechanical properties of alloy 909" 27 : 1092-1097, 2011