High Temperature Tensile Behavior of Directionally Solidified MAR-M247 Superalloy

2014 ◽  
Vol 783-786 ◽  
pp. 1153-1158
Author(s):  
Hui Yun Bor ◽  
Chao Nan Wei ◽  
An Chou Yeh ◽  
Wei Bin He ◽  
Huei Sen Wang ◽  
...  

In this study, two heat treatment schemes were proposed to study the high temperature mechanical behavior of directionally solidified MAR-M247 superalloy. Two withdraw rates, namely, 60 and 180 mm/h were used to produce directionally solidified MAR-M247 specimens by the Bridgeman type furnace. Standard heat treatment (HT1) procedures are solution treatment at 1230°C for 2 h/ArC, then first aging at 980°C for 5 h/AC and followed by second aging at 870°C for 20 h/AC. Modified heat treatment (HT2) is solution treatment at 1260°C for 3 h/ArC and first aging at 980°C for 6 h/AC, then the same second aging procedure. Uneven size, shape and fusion-alike of gamma prime precipitates are observed after full HT1 scheme, whereas even size but fine gamma prime precipitates are observed in HT2 specimen. All three tensile properties (elongation to failure, ultimate tensile strength and yield strength) of HT2 specimens are higher than these of HT1 specimens either at room temperature 25°C or at high temperature 982°C for both withdraw rates. Uneven distribution of the γ′ precipitates attributes to the initial fracture of HT1 specimens.

2014 ◽  
Vol 788 ◽  
pp. 519-524
Author(s):  
Wei Guo Zhang ◽  
Xue Mei Yi ◽  
Chu Ang Feng

The heat treatment of a directionally solidified superalloy under high temperature gradient with different dendritic size was studied. The evolution rules of each phase in DZ125 alloy after heat treatment were analyzed. The results show that γ' phase presents cube and uniform distribution after heat treatment. Its size is about 0.4μm and its area ratio is about 65%. MC carbide transforms into MC(2) carbide with high concentration of Hf. The morphology of MC carbide changes from Chinese-script to block and its size reduces gradually with increasing solidification rate under directional solidification. There is bulk γ' phase around carbide. MC(2) carbide and γ' phase in the grain boundary form chain along grain boundary, and effectively retard grain boundary sliding. γ+γ' eutectic is basically eliminated by solution treatment and only a little γ+γ' eutectic exists around carbide.


2016 ◽  
Vol 849 ◽  
pp. 508-512
Author(s):  
Yang Gao ◽  
Yong Ji Niu ◽  
Shi Feng Shi ◽  
Jian Jun Tian ◽  
Chao Wang ◽  
...  

Large quantities of VIDP400 vacuum furnace smelting DZ417G oriented superalloys smelting process has been researched, analysis of the main factors affecting the organizational uniformity and stability, as well as the impact of high temperature tensile and lasting properties has been studied. The results showed that: At pulling rate of 4.5~8.5mm•min-1, after 1220°C solid solution treatment and 980°C aging system, the DZ417G superalloy had uniform chemical constitution with oxygen and nitrogen content of the alloy in sharply reduced to 13ppm. It can be got available treatment uniform structure with proper γ'phase size, with high-temperature tensile strength up to 750MPa, elongation of 17% reduction of area 22%. The lasting high temperature performance can reach to more than 100 hours.


2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.


2021 ◽  
Vol 1016 ◽  
pp. 906-910
Author(s):  
Xin Hua Min ◽  
Cheng Jin

In this paper,effect of the different forging processes on the microstructure and mechanical properties of the flat flat billets of TA15 titanium alloy was investigated.The flat billiets of 80 mm×150 mm×L sizes of TA15 titanium alloy are produced by four different forging processes.Then the different microstrure and properties of the flat billiets were obtained by heat treatment of 800 °C~850 °C×1 h~4h.The results show that, adopting the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling, the primary αphases content is just 10%, and there are lots of thin aciculate phases on the base. This microstructure has both high strength at room temperature and high temperature, while the properties between the cross and lengthwise directions are just the same. So the hot processing of the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling is choosed as the ideal processing for production of aircraft frame parts.


2017 ◽  
Vol 898 ◽  
pp. 476-479
Author(s):  
Jin Xia Yang ◽  
Yuan Sun ◽  
Dong Ling Zhou

The effects of HIP process on microstructure and mechanical properties of IN792 cast superalloy were studied. The results showed that HIP process produced more uniform and finer cubic γ′ than standard heat treatment. The difference of the mechanical properties should be caused by the microstructure changes. HIP process leads the homogeneous distribution of γ′ at dendritic arm and interdendritic area, and improved UTS and YS of tested alloy at 550°C. However, it played no role in increasing UTS and YS at room temperature and stress-rupture lives of 760°C/662MPa and decreased stress-rupture lives of 982°C/186MPa.


2020 ◽  
Vol 306 ◽  
pp. 53-61
Author(s):  
Sergey V. Astafurov ◽  
Galina G. Maier ◽  
Eugene V. Melnikov ◽  
Valentina A. Moskvina ◽  
Marina Yu. Panchenko ◽  
...  

The paper is devoted to an experimental investigation of a high-temperature deformation in V-alloyed high-nitrogen austenitic Fe-19Cr-22Mn-1.5V-0.3C-0.6N steel processed via different thermo-mechanical treatments. Simple thermo-mechanical processing regimes (cold rolling or rolling with single post-deformation anneal) do not allow to realize a substantial elongation in high-nitrogen steel during high-temperature tensile tests. For fine-grained austenitic structure with an average grain size of 3 µm, the maximal value of elongation to failure of 150% was realized at temperature 950 °C. Using a multi-stage thermo-mechanical treatment included cold rolling and intermediate anneals, a heterophase grain/subgrain structure with high density of deformation-induced defects and precipitates was produced. When heated to a deformation temperature, this deformation-assisted microstructure recrystallizes into a stable fine-grained structure and demonstrates the attributes of superplastic flow (values of elongation to failure higher than 400%) in the temperature range of 850-1000 °C. The maximum elongation of 900% is achieved at temperature of 950 °C and an initial strain rate of 10-4 s-1.


2016 ◽  
Vol 849 ◽  
pp. 570-579
Author(s):  
Qiang Huang ◽  
Jin Xia Song ◽  
Qing Li ◽  
Wei Peng Ren ◽  
Xin Guang Guan ◽  
...  

The microstructures and mechanical properties of superalloy K465 under different heat treatment, including as as-cast, solution treatment and aging, were investigated. The results showed that γ' precipitates in as-cast condition exhibited two kinds of morphologies of fine regular cuboidal shape at dendritic arm and coarse irregular form in interdendritic region. MC carbides decomposed into M6C carbides partly after 1210°C/4h solution treatment. The high temperature stress-rupture life can be improved obviously with the increasing cooling rate. When cooling rate was lower than 70°C/min, the room temperature tensile elongation increased with cooling rate increasing. When cooling rate was higher than 90°C/min the room temperature tensile elongation decreased with cooling rate increasing. The proper cooling rate of 70oC/min~90oC/min is advantageous for the achievement of excellent comprehensive properties. When aging treatments continued the regularization of γ' resulted in the improvement of stress-rupture life and the reduction of tensile elongation. The mechanical property gap between the solution treatment and aging can be decreased with increasing cooling rate.


2017 ◽  
Vol 891 ◽  
pp. 420-425
Author(s):  
Sureerat Polsilapa ◽  
Aimamorn Promboopha ◽  
Panyawat Wangyao

Cast nickel based superalloy, Grade Inconel 738, is a material for turbine blades. Its rejuvenation heat treatment usually consist of solution treatment condition with temperature range of 1125-1205 oC for 2-6 hours. Then it is following with double aging process including primary aging at 1055oC for 1 hour and secondary aging at 845oC for 24 hours. However, the various selected temperature dropping program were performed during solution treatment to simulate the possible error of heating furnace. The maximum number of temperature dropping during solution treatment is varied from 1-3 times From all obtained results, the various temperature dropping during solution treatment conditions showed extremely the significant effect on the final rejuvenated microstructures and long-term gamma prime stability after heating at temperature of 900oC for 200 hours.


Sign in / Sign up

Export Citation Format

Share Document