Effect of Carbon on the Microstructural Evolution and Thermal Fatigue Behavior of a Ni-Base Superalloy

2016 ◽  
Vol 849 ◽  
pp. 497-502 ◽  
Author(s):  
Ning An ◽  
Yang An ◽  
Qiang Fan ◽  
Zu Ming Fu ◽  
Zhen Rui Li ◽  
...  
Keyword(s):  
Carbon Content ◽  
Microstructural Evolution ◽  
Thermal Fatigue ◽  
Volume Fraction ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Properties ◽  
Thermal Fatigue Behavior ◽  
Thermal Fatigue Cracks ◽  
Base Superalloy

The effect of carbon content on the microstructural evolution and thermal fatigue behavior of Ni-Cr-Fe-Mo alloy with different carbon content was carried out at temperature ranging from 20°C to 920°C. The microstructure evolution was detected and the length of thermal fatigue cracks was measured. The results revealed that all the alloys are mainly composed of γ phase and carbides. With the increase of carbon content, the volume fraction of carbides increase and the morphology varies from blocky to script-like and sheet-like. The microstructural features exert influence on the thermal fatigue cracks of the alloys with different carbon content. Considering the thermal fatigue properties, the optimum carbon content of the Ni-Cr-Fe-Mo alloy superalloy should be below 0.08wt.%.

Effect of Fiber Volume Fraction on Low Cycle Fatigue Behavior of Al2O3f/Al-Si Composites

2012 ◽  
Vol 268-270 ◽  
pp. 87-91
Author(s):  
Jian Jun Cui ◽  
Bing Chao Li ◽  
Guo Hua Zhang ◽  
Jian Xin Zhang ◽  
Zuo Shan Wei ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Short Fibers ◽  
Fiber Volume ◽  
Large Size

The tensile and low cycle fatigue tests were carried out on alumina short fibers reinforced Al-Si piston alloy composites (Al-Si MMCs). Three Al-Si MMCs reinforced with 10, 17 and 25 vol.% of alumina short fibers were prepared to investigate the effects of volume fraction on tensile and low cycle fatigue properties at room temperature (RT) and 350°C. The results showed that the tensile strength decreased with the increasing of volume fraction of fibers at RT and was slight different at 350°C. Among the three MMCs, the 17%-MMCs showed highest stress level under the low cycle fatigue tests. The fatigue cracks were usually initiated from the clustered and large size fibers near the surface of specimen, propagated along the fiber/matrix interface at RT and grew rapidly by means of broken the fibers at 350°C.

Effect of Fiber Volume Fraction on Low Cycle Fatigue Behavior of Al2O3f/Al-Si Composites

2012 ◽  
Vol 622-623 ◽  
pp. 1340-1344
Author(s):  
Jian Jun Cui ◽  
Bing Chao Li ◽  
Guo Hua Zhang ◽  
Jian Xin Zhang ◽  
Zuo Shan Wei ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Short Fibers ◽  
Fiber Volume ◽  
Large Size

The tensile and low cycle fatigue tests were carried out on alumina short fibers reinforced Al-Si piston alloy composites (Al-Si MMCs). Three Al-Si MMCs reinforced with 10, 17 and 25 vol.% of alumina short fibers were prepared to investigate the effects of volume fraction on tensile and low cycle fatigue properties at room temperature (RT) and 350°C. The results showed that the tensile strength decreased with the increasing of volume fraction of fibers at RT and was slight different at 350°C. Among the three MMCs, the 17%-MMCs showed highest stress level under the low cycle fatigue tests. The fatigue cracks were usually initiated from the clustered and large size fibers near the surface of specimen, propagated along the fiber/matrix interface at RT and grew rapidly by means of broken the fibers at 350°C.

High-Temperature Low-Cycle Fatigue Behavior of 625 Nickel-Base Superalloy Welding Joint

2014 ◽  
Vol 618 ◽  
pp. 120-124
Author(s):  
Yuan Yuan Wang ◽  
Bao Sen Wang ◽  
Li Jia Chen
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Properties ◽  
Nickel Base Superalloy ◽  
Cycle Fatigue ◽  
Welding Joint ◽  
Nickel Base ◽  
Base Superalloy

High temperature low cycle fatigue properties and fracture behavior of Inconel 625 nickel-base superalloy welding joint at 760oC were investigated under fully reversed total strain-controlled mode. The fatigue life and cyclic stress-strain data were analyzed to determine the individual strain fatigue parameters. It is noted that the welding joint exhibits the cyclic strain hardening and stability. The fatigue cracks initiate predominantly on the free surface of fatigue specimens and propagate in an intergranular mode or a mixed transgranular and intergranular mode.

Evaluation of Microstructural Evolution and Thermal Fatigue Crack Initiation in Sn-Ag-Cu Solder Joints

2003 ◽  
Author(s):  
Toshihiko Sayama ◽  
Takeshi Takayanagi ◽  
Yoshiaki Nagai ◽  
Takao Mori ◽  
Qiang Yu
Keyword(s):  
Microstructural Evolution ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Growth Parameters ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Phase Growth ◽  
Thermal Fatigue Crack ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

Thermal fatigue damage in solder joints is believed to be closely related to microstructural evolution. In this study, a microstructural approach will be taken to evaluate the lifetime of Sn-3.0Ag-0.5Cu lead-free solder joints before the initiation of thermal fatigue cracks. In order to clarify the relation between the microstructural change and the initiation of thermal fatigue cracks, a series of thermal cycle tests were performed using fabricated PCBs on which various chip resistors were mounted. The following results were obtained via SEM observations. First, both the β-Sn and the Ag3Sn phases grow as the number of cycles N increases. This phase growth is characterized by phase growth parameters Ss and SA in the β-Sn phase and the Ag3Sn phase, respectively, which are defined as the average phase size to the 4th power. The phase growth proceeds such that the parameters increase proportionally to N. Furthermore, simple relations exist between the average number of cycles leading to the initiation of thermal fatigue cracks Ni and the average increase in the parameters per cycle ΔSs or ΔSA. That is, power law relations ΔSs = C2Ni−β and ΔSA = C3Ni−γ are determined. These relationships will enable us to evaluate the lifetime of the solder joints before the initiation of thermal cracks based on observations of microstructural evolution.

Improvement of Thermal Fatigue Resistance of A Wrought Nickel-Base Superalloy by Laserglaze

1985 ◽  
Vol 58 ◽  
Author(s):  
Zhao Qi ◽  
Ge Yunlong ◽  
Hu Zhuangqi ◽  
Jiang Ming ◽  
Shih Changshu
Keyword(s):  
Heat Treatment ◽  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
Fatigue Cracks ◽  
Nickel Base Superalloy ◽  
Post Heat Treatment ◽  
Thermal Fatigue Resistance ◽  
Nickel Base ◽  
Thermal Fatigue Cracks ◽  
Base Superalloy

ABSTRACTLaserglaze with appropriate post heat treatment has improved the thermal fatigue resistance of a wrought nickel-base superalloy. It was found that laserglaze was able to eliminate the blocky MC phase, refine grains and form a very interesting microstructure of serrated grain boundaries. Careful selection of post heat treatment markedly increased the strength in the laser irradiated region. The initiation and propagation of thermal fatigue cracks were suppressed by this novel microstructure.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

scholarly journals Quantitative Analysis of Inclusion Engineering on the Fatigue Property Improvement of Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 476 ◽  
Author(s):  
Chao Gu ◽  
Min Wang ◽  
Yanping Bao ◽  
Fuming Wang ◽  
Junhe Lian
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
Bearing Steels ◽  
Inclusion Distribution

The fatigue property is significantly affected by the inner inclusions in steel. Due to the inhomogeneity of inclusion distribution in the micro-scale, it is not straightforward to quantify the effect of inclusions on fatigue behavior. Various investigations have been performed to correlate the inclusion characteristics, such as inclusion fraction, size, and composition, with fatigue life. However, these studies are generally based on vast types of steels and even for a similar steel grade, the alloy concept and microstructure information can still be of non-negligible difference. For a quantitative analysis of the fatigue life improvement with respect to the inclusion engineering, a systematic and carefully designed study is still needed to explore the engineering dimensions of inclusions. Therefore, in this study, three types of bearing steels with inclusions of the same types, but different sizes and amounts, were produced with 50 kg hot state experiments. The following forging and heat treatment procedures were kept consistent to ensure that the only controlled variable is inclusion. The fatigue properties were compared and the inclusions that triggered the fatigue cracks were analyzed to deduce the critical sizes of inclusions in terms of fatigue failure. The results show that the critical sizes of different inclusion types vary in bearing steels. The critical size of the spinel is 8.5 μm and the critical size of the calcium aluminate is 13.5 μm under the fatigue stress of 1200 MPa. In addition, with the increase of the cleanliness of bearing steels, the improvement of fatigue properties will reach saturation. Under this condition, further increasing of the cleanliness of the bearing steel will not contribute to the improvement of fatigue property for the investigated alloy and process design.

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