scholarly journals Effect of Hot Isostatic Pressing on Microstructures and Stress-Rupture Properties of CM 939 Weldable Alloy

2022 ◽  
Vol 2160 (1) ◽  
pp. 012024
Author(s):  
Yongfeng Sui ◽  
Zhonghua Liu ◽  
Yao Tu ◽  
Peijiong Yü ◽  
Peng Chu
Keyword(s):  
Rupture Life ◽  
Hot Isostatic Pressing ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Isostatic Pressing ◽  
Stress Rupture Properties ◽  
Weldable Alloy ◽  
Rupture Properties

Abstract Effect of hot isostatic pressing (HIP) treatment on the microstructure and the stress rupture properties of CM 939 Weldable alloy have been investigated. The results shown that the HIP has the function of densification and homogenization, all of the microporosity have been almost removed, the segregation of the alloy have been reduced, the microstructure became better, the stress rupture life of CM 939 Weldable alloy have been obviously improved, Meanwhile, the data dispersion of stress rupture properties have been reduced for the alloy after HIP.

scholarly journals Influence Mechanism of Silicon on Carbide Phase Precipitation of a Corrosion Resistance Nickel Based Superalloy

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 959 ◽  
Author(s):  
Tao Liu ◽  
Mei Yang ◽  
Fenfen Han ◽  
Jiasheng Dong
Keyword(s):  
Carbide Phase ◽  
Silicon Content ◽  
Rupture Life ◽  
Stress Rupture ◽  
Low Carbon ◽  
Stress Rupture Life ◽  
Corrosion Resistant ◽  
Stress Rupture Properties ◽  
Corrosion Resistant Alloy ◽  
Rupture Properties

The effect of silicon on diffusion behavior of the carbide forming elements in Ni-Mo-Cr-Fe based corrosion-resistant alloy is studied by diffusion couple experiment. One group of diffusion couples are made of the alloy with a different silicon content, another group of diffusion couples are made of pure nickel and the alloy with different silicon content (0Si, 2Si). Two groups of alloys with same silicon content and different carbon content are also prepared, the microstructure of solution and aging state of these two groups alloys are analyzed, and their stress rupture properties are tested. The effect of silicon on the diffusion of alloy elements and the interaction effect of carbon and silicon on the microstructure and stress rupture properties of the alloy are analyzed. The mechanism of Si on the precipitation behavior of carbide phase in Ni-Mo-Cr-Fe corrosion resistant alloy is discussed. The results show that silicon can promote the diffusion of carbide forming elements and the formation of carbide. The precipitation behavior of the secondary phase is the result of the interaction effect of silicon and carbon, and is related to the thermal history of the alloy. Combined with the characteristic of primary carbides, it is confirmed that the precipitation of M12C type secondary carbide is caused by the relative lack of carbon element and the relative enrichment of carbide forming elements such as molybdenum. The stress rupture properties of two silicon-containing alloys with different carbon contents in solution and aging state are tested. The stress rupture life of low carbon alloy is lower compared with high carbon alloy at solution state, but after aging treatment, the stress rupture life of low carbon alloy is significantly improved, and higher than that of high carbon alloy. The main aim of this research is to reveal the influence mechanism of silicon on carbide phase precipitation of a Ni-Mo-Cr-Fe based corrosion-resistant superalloy, which provides theoretical basis and reference for later alloy design and engineering application.

Heat Treated Microstructure and Mechanical Properties of K492M Alloy

2014 ◽  
Vol 788 ◽  
pp. 493-497
Author(s):  
Xiang Hui Li ◽  
Lian Li ◽  
Xin Tang ◽  
Qi Dong Gai
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Interdendritic Region ◽  
Rupture Life ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Stress Rupture Properties ◽  
Heat Treated ◽  
Columnar Grain ◽  
Rupture Properties

The microstructure, tensile and stress rupture properties of K492Malloy have been investigated in the present study. The results revealed that γ matrix, γ′ phase, carbide and eutectic in the interdendritic region within grain interior and along grain boundary were observed after solidification. After heat treatment, γ' precipitates with two obviously distinct size existed in the dendrite core and interdendritic region, respectively. Meanwhile, the chain-like (W, Mo)6C and Cr23C6carbides precipitated along grain boundary. The investigation of mechanical properties suggested that the tensile strength was initially increased but then decreased with increasing the temperature from 25oC to 760oC. The stress rupture life was 68.2h and 35.8h at 760oC / 655MPa and 870oC / 365MP, respectively. The columnar grain and carbide along grain boundary resulted in intergranular brittle fracture in both test conditions. As a result, the elongation under the conditions of 760oC/655MPa and 870oC/365MP was 1.5% and 1.4%, respectively.

Effects of Ru Additions on the Microstructures and Stress Rupture Life of a Directionally Solidified Ni-Based Cast Superalloy

2007 ◽  
Vol 546-549 ◽  
pp. 1201-1206 ◽  
Author(s):  
Xiao Lei Han ◽  
Ya Fang Han ◽  
Shu Suo Li ◽  
Wen You Ma
Keyword(s):  
Rupture Life ◽  
Stress Rupture ◽  
Aging Treatment ◽  
Incipient Melting ◽  
Directionally Solidified ◽  
Stress Rupture Life ◽  
Stress Rupture Properties ◽  
Heat Treated ◽  
Rupture Properties ◽  
Cast Superalloy

Two directionally solidified (DS) Ni-based cast superalloys without and with 3wt. % Ru were prepared. The effects of Ru addition on the microstructures and stress rupture properties of the heat treated superalloys were investigated. It is shown that the amount of eutectic in 3wt. % Ru alloy was less than that in alloy without Ru. The incipient melting structure was found after quenching followed by 1295°C and 1300°C solid solution treatments in 3wt. % Ru alloy and in the alloy without Ru, respectively. The temperature at which the eutectic pools dissolved completely was higher than the temperature at which incipient melting appears. In order to obtain the better mechanical properties, double aging treatment was carried out for both alloys to optimize the sizes, morphologies and distribution of the γ′ phase. The stress rupture lives of the alloys were 55h and 108h under the condition of 1070°C and 137MPa the alloys without Ru and with 3wt. % Ru respectively. It is suggested that 3wt. % Ru addition can prolong the stress rupture life of the alloy.

Effect of Hot Isostatic Pressing on Microstructures and Mechanical Properties of IN738LC Superalloy

2017 ◽  
Vol 898 ◽  
pp. 401-406
Author(s):  
Qun Gong He ◽  
Jun Liu ◽  
Lin Xu Li ◽  
Zhen Huan Gao ◽  
Xiao Yan Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Rupture Life ◽  
Hot Isostatic Pressing ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Isostatic Pressing ◽  
Microstructures And Mechanical Properties ◽  
The Impact

The microstructures and mechanical properties of IN738LC superalloy made by investment castings followed by Hot Isostatic Pressing (HIP) treatment have been investigated. The results revealed that after HIP treatment, the microporosities have been almost removed and the density rose by 0.21%. The eutectic size became smaller and the fraction decreased. The γ' phase was more regular and also increased in size, while a large number of secondary γ' phase appeared. With HIP treatment, the impact toughness increased from 5.0J ~ 7.0J to 8J ~ 9J and tensile strength at 200°C ~ 800°C was improved by approximately 3.2%~19.7%. In addition, the ductility and the stress rupture life have also been greatly improved as well.

Microstructure Evolution and Stress Rupture Properties of DD6 Single Crystal Superalloy after Overheating

2017 ◽  
Vol 898 ◽  
pp. 517-522 ◽  
Author(s):  
Shi Zhong Liu ◽  
Zhen Xue Shi ◽  
M. Han ◽  
Jia Rong Li
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Rupture Life ◽  
Stress Rupture ◽  
Standard Heat Treatment ◽  
Stress Rupture Life ◽  
Matrix Channel ◽  
Standard Heat ◽  
Stress Rupture Properties ◽  
Rupture Properties

The second generation single crystal superalloy DD6 after standard heat treatment was respectively overheated at 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1320°C for 1h and air cooled. The effect of overheating on the microstructure and stress rupture properties at 980°C/250MPa of the alloy was investigated. The results showed that the size of γ′ phase was slightly increased overheating at 1100°C, 1150°C and 1200°C. The size of γ′ phase had a big increase and its size distribution was very uneven after overheating at 1250°C. The small part of γ′ phase has serrated γ′/γ phase surface as a result of un-completely solution and the irregular small γ′ phase was in the majority when overheated at 1300°C. While all the irregular small γ′ phase precipitated again after completely solution when overheated at 1320°C. There was no fine second γ′ phase in the γ matrix channel of the alloy after standard heat treatment and overheating at 1320°C. But the fine second γ′ phase precipitated in the γ matrix channel after overheating at every temperature of 1100 °C~1300°C. No obvious change of the stress rupture life was found after overheating at 1100°C, 1150°C, 1200°C and 1250°C. The stress rupture life considerably reduced after overheating at 1300°C, whereas slightly reduced after overheating at 1320°C. The appearance of the raft had almost no change after overheating at 1100°C. With increasing of overheating temperature from 1100°C to 1250°C, the length of raft became shorter and the width thickening. The γ phase formed the wavy raft after overheating at 1300°C and 1320°C and the thickness of latter was larger than that of the former. Finally, the relationship between the microstructural evolution and stress rupture properties of the alloy after overheating was discussed.

Influence of Withdrawal Rate on Tensile and Stress Rupture Properties of the Single Crystal Superalloy DD9

2013 ◽  
Vol 747-748 ◽  
pp. 625-628 ◽  
Author(s):  
Z.X. Shi ◽  
J.R. Li ◽  
Shi Zhong Liu
Keyword(s):  
Single Crystal ◽  
Rupture Life ◽  
Stress Rupture ◽  
Single Crystal Superalloy ◽  
Withdrawal Rate ◽  
Stress Rupture Life ◽  
The Third ◽  
Stress Orientation ◽  
Stress Rupture Properties ◽  
Rupture Properties

The third generation single crystal superalloy DD9 was processed with different withdrawal rates and the effect of withdrawal rate on the tensile and stress rupture properties of the alloy was investigated. The relation between the mechanical properties and microstructure of the alloy with different withdrawal rates was discussed. The results showed that the withdrawal rate had a little effect on the tensile properties at 25 of the alloy. The tensile strength at 980 and stress rupture life at 1120/140MPa of DD9 alloy all increased with the increasing of withdrawal rate. The γ precipitates of specimen tensile at 25 had a little extension in the stress orientation. The extension of γ precipitates in the stress orientation at 980 was much more than that at 25. The vertical γ matrix at 980 became thinner and horizontal γ matrix became thicker slightly. The γ precipitates of those had rafted in a direction transverse to the applied stress.

scholarly journals Influence of Phosphorus Addition on the Stress Rupture Properties of Direct Aged IN706 Superalloy

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 641
Author(s):  
Sha Zhang ◽  
Anwen Zhang ◽  
Chaochao Xue ◽  
Dan Jia ◽  
Weiwei Zhang ◽  
...  
Keyword(s):  
Rupture Life ◽  
Stress Rupture ◽  
Phosphorus Addition ◽  
Stress Rupture Life ◽  
P Concentration ◽  
Stress Rupture Properties ◽  
Rupture Properties ◽  
The Relationship ◽  
P Addition

This study investigated the influence of phosphorus (P) addition on the stress rupture properties of direct aged IN706 superalloy. The results showed that P slightly improved the stress rupture life of the superalloy when added in the range between 0.002% and 0.008%; however, it significantly reduced the stress rupture life when added in the range between 0.013% and 0.017%. Microstructure characterization indicated that the precipitation of γ′, γ″, and η phases was not significantly affected by the addition of P. Phosphides precipitated in the alloy containing 0.017% P after aging at 980 °C for 10 min. Compared to a similar study previously made on IN706 superalloy, it was found that the optimum P concentration in the as-solutioned state for improving the stress rupture properties was not definite. Furthermore, the relationship between the amount of P segregated at the grain boundary and the role of P on the stress rupture properties was discussed.

Stress Rupture Properties of the Second Generation Single Crystal Superalloy DD6 after High Temperature Exposure

2007 ◽  
Vol 546-549 ◽  
pp. 1249-1252 ◽  
Author(s):  
Hai Peng Jin ◽  
Jia Rong Li ◽  
Shi Zhong Liu
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Second Generation ◽  
Rupture Life ◽  
Stress Rupture ◽  
Single Crystal Superalloy ◽  
Stress Rupture Life ◽  
Stress Rupture Properties ◽  
Temperature Exposure ◽  
Rupture Properties

The effects of high temperature exposure simulating service conditions on stress rupture properties were studied for the second generation single crystal superalloy DD6. The specimens with [001] orientation were exposed in air at temperatures of 980°C and 1070°C for 100h to 1000h. They were then tested using conventional mechanical tests at 1070°C/140MPa to determine the effects of exposure on stress rupture properties. The analysis indicated that stress rupture life decreased with increasing exposure time. At the temperature of 980°C, the stress rupture life is more than 180h after exposure for 1000h. When the test temperature increased to 1070°C, the stress rupture life exceeds 100h after 800h exposure. The morphology of γ prime phase after exposure was observed by using scanning electron microscopy (SEM). Morphologies evaluations have shown that alloy DD6 exhibits excellent microstructure stability after exposure. TCP (Topologically Closed Packed) phases have not been observed. It has been also found that the morphology and size of γ prime affected stress rupture life of the alloy. The decrement in stress rupture life with increasing exposure is a result of γ prime rafting.

Influence of Aging Temperature on the Microstructure and Stress Rupture Property of DZ951 Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1241-1244 ◽  
Author(s):  
P.C. Xia ◽  
Jin Jiang Yu ◽  
Xiao Feng Sun ◽  
Heng Rong Guan ◽  
Zhuang Qi Hu
Keyword(s):  
Ductile Fracture ◽  
Aging Temperature ◽  
Cast Alloy ◽  
Rupture Life ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Stress Rupture Property ◽  
Stress Rupture Properties ◽  
Rupture Properties ◽  
Strength And Ductility

Effect of different aging temperatures on microstructure and stress rupture properties of DZ951 alloy were investigated in this paper. The results show that the shape of carbide changed from script-like in as-cast alloy to block during different aging treatments. MC carbide degrades into M23C6 at the aging temperature of 970°C, which made alloy have a better combination of strength and ductility than that at other aging temperatures. The size of γ′ phase increases and the shape of γ′ phase changed from sphere (870°C) to quasi-cuboid (920°C) and cuboid (970°C) with the increasing aging temperature. The stress rupture life of DZ951 alloy at 1100°C/60MPa improves with the increased of aging temperature. The fractographs at different conditions showed a ductile fracture mode.

Effect of Long-Term Aging on the Microstructures and Stress Rupture Properties of a Ni-Based Single Crystal Superalloy at 980°C

2014 ◽  
Vol 788 ◽  
pp. 560-564 ◽  
Author(s):  
Jian Wei Xu ◽  
Li Li Cui ◽  
Hai Wen Wang
Keyword(s):  
Single Crystal ◽  
Rupture Life ◽  
Interface Reaction ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Phase Coarsening ◽  
Precipitated Phase ◽  
Stress Rupture Properties ◽  
Rupture Properties

The effect of aging time at 980°C on the microstructures and mechanic properties for a single crystal Ni-based superalloy was investigated in this paper. The results showed that γ’ size distribution portrayed a low growth rate and maintained well cubic during aging for 0~1000h at 980°C. However, γ’ phase was gradually coarsened directionally during the aging for 1000~2500h at 980°C, indicating that the γ’ phase coarsening was controlled by diffusion during aging for 0~1000h at 980°C. In addition, the γ’ phase coarsening was also susceptible to the interface reaction during aging for 1000~2500h at 980°C. Furthermore the precipitated phase was analyzed, and the results showed that only slightly Topologically Close-Packed (TCP) phase was precipitated after aging for 1500h at 980°C which indicates that the microstructures of alloy were stable during aging for up to 1500 hours. At the same time, stress rupture life decreased rapidly for 0~250h, but basically kept constant value when aged for 250~1500h, then decreased rapidly again aging for 1500~2000h.

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