Creep-rupture behavior of iridium at elevated temperatures

1975 ◽  
Vol 6 (4) ◽  
pp. 885-889 ◽  
Author(s):  
R. L. Mehan ◽  
E. C. Duderstadt ◽  
E. H. Sayell
Author(s):  
M.M. Barjesteh ◽  
S.M. Abbasi ◽  
K.Z. Madar ◽  
K. Shirvani

Creep deformation is one of the life time limiting reasons for gas turbine parts that are subjected to stresses at elevated temperatures. In this study, creep rupture behavior of uncoated and platinum-aluminide coated Rene?80 has been determined at 760?C/657 MPa, 871?C/343 MPa and 982?C/190 Mpa in air. For this purpose, an initial layer of platinum with a thickness of 6?m was applied on the creep specimens. Subsequently, the aluminizing were formed in the conventional pack cementation method via the Low Temperature-High Activity (LTHA) and High Temperature-Low Activity (HTLA) processes. Results of creep-rupture tests showed a decrease in resistance to creep rupture of coated specimen, compared to the uncoated ones. The reductions in rupture lives in LTHA and HTLA methods at 760?C/657 MPa, 871?C/343 MPa and 982?C/190 MPa were almost (26% and 41.8%), (27.6% and 38.5%) and (22.4% and 40.3%), respectively as compared to the uncoated ones. However, the HTLA aluminizing method showed an intense reduction in creep life. Results of fractographic studies on coated and uncoated specimens indicated a combination of ductile and brittle failure mechanisms for all samples. Although, the base failure mode in substrate was grain boundary voids, cracks initiated from coating at 760?C/657MPa and 871?C/343. No cracking in the coating was observed at 982?C/190MPa.


1973 ◽  
Vol 40 (1) ◽  
pp. 244-250 ◽  
Author(s):  
D. R. Hayhurst

A uniaxial theory of low-stress, high-temperature creep rupture has been shown to predict the results of uniaxial creep rupture tests. By including the creep rupture relationships into the accepted multiaxial deformation laws and following the numerical procedure outlined in a previous publication, a lower bound on the rupture time has been obtained for the case of a biaxially loaded plate containing a small hole at its center. It has been shown that the rupture behavior of the structure is controlled by a single stress whose magnitude is independent of the form of the constitutive relationship. The results of the prediction method agreed well with the experimentally determined values for aluminum plates tested at elevated temperatures.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Ryuya Takanashi ◽  
Yoshinori Ohashi ◽  
Wataru Ishihara ◽  
Kazushige Matsumoto

AbstractCross-laminated timber (CLT) has been used extensively in timber construction. CLT panels are typically used in roofs and floors that carry a continuous load, and it is important to examine the long-term loading capacity of CLT. However, studies that focus on the long-term loading capacity of CLT are limited. To this end, we conducted long-term out-of-plane bending tests on seven-layer CLT made from Japanese larch (Larix kaempferi) under constant environmental conditions, investigated creep performance and duration of load, and experimentally analyzed creep rupture behavior. The mean estimated relative creep after 50 years was 1.49. The sample showed a satisfactory resistance to creep as a building material. The duration of load of most of the specimens in this study was shorter than the conventional value of small clear wood specimens. Specimens had a lower duration of load capacity than solid lumber. According to the results of survival analysis, a loading level of 70% or more caused the initial failure of specimens. Creep rupture of most of the specimens occurred at less deflection than displacement at failure in the short-term loading test. Additional studies focusing on the effects of finger joints, transverse layers, and width of a specimen on creep rupture behavior are suggested.


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.


1996 ◽  
Vol 45 (12) ◽  
pp. 1328-1333 ◽  
Author(s):  
Hiromichi HONGO ◽  
Masayoshi YAMAZAKI ◽  
Takashi WATANABE ◽  
Junichi KINUGAWA ◽  
Yoshio MONMA

2000 ◽  
Vol 76 (1-3) ◽  
pp. 153-161 ◽  
Author(s):  
Piyush K. Dutta ◽  
David Hui

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