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Your search keyword '"Chaturvedi, M. C."' showing total 267 results
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267 results on '"Chaturvedi, M. C."'

48. On liquation and liquid phase oxidation during linear friction welding of nickel-base in 738 and CMSX 486 superalloys

Author

Amegadzie, M. Y., Ola, O. T., Ojo, O. A., Priti Wanjara, and Chaturvedi, M. C.

Subjects
Nickel base superalloy, Compressive stress, Welds, technology, industry, and agriculture, Conventionally casts, Liquids, Mechanical properties, respiratory system, Thermomechanical treatment, Thermomechanical simulation, Liquid-phase oxidation, Nickel, Oxidation, Atmospheric oxygen, Micro-structural, Oxide films, Linear friction welding, Friction welding, Liquation, Superalloys
Abstract

A systematic study of the microstructural response of conventionally cast IN 738 and single crystal CMSX 486 superalloys during linear friction welding was performed. The results revealed that, aside from a significant liquation of various phases that occurred during joining, continuous oxide films formed on the weld lines in both materials. The weld line oxides consisted of aluminum-rich and hafnium-base oxides in IN 738 and CMSX 486 superalloys, respectively, which can be deleterious to the mechanical properties of the weld joint. Gleeble thermo-mechanical simulation showed that the oxides were produced by the oxidation of some liquid exposed to atmospheric oxygen at the mating surfaces of the work pieces. A practicable method of eliminating liquid phase oxidation during linear friction welding of nickel-base superalloys is discussed., 12th International Symposium on Superalloys, Superalloys 2012, 9 September 2012 through 13 September 2012, Seven Springs, PA

Published
2012

49. Effect of Different Solution Heat Treatments on the Hot Ductility of Superalloys : Part 3 - Waspaloy

Author

Andersson, Joel, Sjöberg, G., Viskari, L., Chaturvedi, M. C., Andersson, Joel, Sjöberg, G., Viskari, L., and Chaturvedi, M. C.

Abstract

The susceptibility to heat affected zone cracking of Waspaloy has been investigated in terms of its hot ductility, measured as the reduction of area (RA). Gleeble testing with on-heating as well as on-cooling test cycles was carried out to illuminate the influence of different 4 h solution heat treatments between 996 and 1080°C. A ductility maximum of between 80 and 90%RA was found at 1050–1100°C for all conditions in the on-heating tests. Although the different heat treatment conditions showed similar macrohardness, the particle size and distribution of the γ′ and M23C6 phases differed, which significantly affected the on-heating ductility in the lower temperature test region. The ductile to brittle transition was initiated at 1100°C in the on-heating testing with indications of grain boundary liquation at the higher test temperatures. Ductility recovery, as measured in the on-cooling tests from 1240°C, was very limited with <30%RA for all conditions and test temperatures except for the 1080°C/4 h treatment, which exhibited 60%RA at 980°C.

Published
2013
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