Effect of Melt Treatment on the Microstructure and Creep-Rupture Behavior of M963 Cast Nickel-Base Superalloy

2004 ◽  
Vol 449-452 ◽  
pp. 553-556
Author(s):  
Heng Rong Guan ◽  
Feng Shi Yin ◽  
Xiao Feng Sun ◽  
Zhuang Qi Hu

The effect of melt treatment on the microstructure and creep-rupture behavior of M963 superalloy at 1248K under 225MPa has been investigated. The microstructure of the as-cast superalloy without melt treatment consists of γ solid solution matrix, γ´precipitate, coarse blocky MC carbide and (γ+γ´)eutectic. The striking difference in microstructure is that the melt treatment changes the MC carbide from the coarse blocky morphology into the fine script-like morphology. After heat-treated at 1483K for 4h followed by air-cooling, both the creep life and rupture elongation of the melt-treated alloy are all doubled those of the alloy without melt treatment. The mechanism of the melt treatment on the creep-rupture behavior of the M963 superalloy is discussed.

2001 ◽  
Vol 32 (5) ◽  
pp. 1103-1110 ◽  
Author(s):  
J. T. Guo ◽  
C. Yuan ◽  
H. C. Yang ◽  
V. Lupinc ◽  
M. Maldini

Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.


2004 ◽  
Vol 449-452 ◽  
pp. 549-552 ◽  
Author(s):  
Xiao Feng Sun ◽  
Feng Shi Yin ◽  
Heng Rong Guan ◽  
Zhuang Qi Hu

The tensile deformation behavior of M963 superalloy treated by various heat treatments has been studied at both room and high temperature (1173K). The result shows that the alloy treated by the standard solution treatment at 1483K for 4h followed by air-cooling has low ductility especially at 1173K. The additional aging treatment at 1123K for 16h followed by furnace cooling can recover the ductility of the alloy at 1173K, but further decrease its room temperature ductility. The TEM observation shows that the deformation mechanism varied with both the testing temperature and heat treatment. Finally, the mechanism of the aging treatment on the deformation behavior of the M963 superalloy is discussed.


2005 ◽  
Vol 475-479 ◽  
pp. 673-676
Author(s):  
D.Y. Yang ◽  
Tao Jin ◽  
Na Ru Zhao ◽  
Zhi Wang ◽  
Xiao Feng Sun ◽  
...  

The precipitation behavior during ageing treatment of a single crystal nickel-base superalloy was investigated by SEM and TEM. The results showed that tetragonal needle-like σ phase and blocky -W phase precipitated during low temperature ageing treatment after this testing alloy was completely solution heat treated. σ and -W phases robbed of solid solution strengthening alloying element W、Mo in the matrix and degraded high temperature creep rupture property severely. The creep curve of the crystal tested at 1010 °C and 248 MPa exhibited that the steady state creep rate ε was as high as 9.46 × 10-3/h. The creep-rupture life was only 25 hours. -W phase was not formed by decrease of W content properly. A relatively low level of Co could inhibit σ phase precipitation and improve microstructural stability.


2011 ◽  
Vol 462-463 ◽  
pp. 1244-1249 ◽  
Author(s):  
Omar Bapokutty ◽  
Zainuddin Sajuri ◽  
Junaidi Syarif ◽  
A.R. Said

The effect of heat treatment on tensile and creep properties of nickel-base superalloy, Inconel 718 in room and at high temperature was investigated. Solution treatment was applied on the as-received material at 980oC for 1 hour before water quenched followed by double aging treatments at 720oC and 621oC for 8 hours, respectively and then cooled in air. The tensile strength at elevated temperatures of 550oC and 650oC were slightly deteriorated for heat treated and as-received materials. Beside strength, significant difference was observed in the elongation. The elongation of heat treated samples drastically reduced to 4 to 5% only compared to that of the as received materials which exhibited more than 30% elongation. The significant increased in tensile strength is suspected due to the present of γ’, γ” and δ precipitates which pinned the movement of grain boundary and sliding. However, the present of these precipitates caused the material to become harder and brittle. Moreover, the increase in load from 70% to 90% UTS and in temperature significantly accelerated the creep rate.


1998 ◽  
Vol 120 (2) ◽  
pp. 375-382 ◽  
Author(s):  
J. A. Daleo ◽  
J. R. Wilson

Very few property data on this common turbine blade alloy have been published. As longer hours of service are accumulated, maintenance considerations such as developing optimum component life strategies and repair processes become important. The lack of specific material data hampers the effort of users and repair facilities to achieve optimum service from this alloy. This study measured some of the basic mechanical and metallurgical characteristics of this polycrystalline nickel base superalloy. Tensile and short-term creep rupture properties as well as microstructural and fracture characteristics are presented. Both the as-heat-treated and thermally exposed characteristics at two different temperatures are examined.


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