Effect of Long-Term Aging on the Tensile Properties of Nickel-Based Superalloy

2012 ◽  
Vol 430-432 ◽  
pp. 7-11 ◽  
Author(s):  
Li Wei Xu ◽  
Hua Bing Li ◽  
Qi Feng Ma ◽  
Zhou Hua Jiang
Keyword(s):  
Strain Rate ◽  
Tensile Properties ◽  
Aging Time ◽  
High Strain ◽  
Dislocation Motion ◽  
Strengthening Phase ◽  
Obvious Effect ◽  
Nickel Based Superalloy ◽  
Coordination Ability

The influence of microstructure evolution of a nickel-based superalloy after long-term aging on the tensile properties and deformation behavior was investigated. The results shows that the aging time exhibits an significant effect on the strength of alloy under low strain rate and the elongation decrease with increasing the aging time, but the aging time has no obvious effect on the strength of the alloy and elongation is affected significantly by aging time. During deformation under high strain rate, the dislocation motion is blocked and the dislocation can not release in time, the strengthening phase peak size effect does not appear in the aging time ranging from 0h to 1000h, so the influent of aging time on the strength of the alloy is not obvious. After long-term aging, no precipitation appear in both sides of the grain boundary which leads to the coordination ability of plastic deformation of grain boundaries reducing, so the ductility of the alloy decreases rapidly in a short aging time.

Impact tensile behavior and frequency response of 3D braided composites

2011 ◽  
Vol 82 (3) ◽  
pp. 280-287 ◽  
Author(s):  
Xuehui Gan ◽  
Jianhua Yan ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Tensile Properties ◽  
High Strain ◽  
Tensile Modulus ◽  
Tensile Failure ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Braided Composites ◽  
3D Braided Composites

The uniaxial tensile properties of 4-step 3D braided E-glass/epoxy composites under quasi-static and high-strain rate loadings have been investigated to evaluate the tensile failure mode at different strain rates. The uniaxial tensile properties at high strain rates from 800/s to 2100/s were tested using the split Hopkinson tension bar (SHTB) technique. The tensile properties at quasi-static strain rate were also tested and compared with those in high strain rates. Z-transform theory is applied to 3D braided composites to characterize the system dynamic behaviors in frequency domain. The frequency responses and the stability of 3D braided composites under quasi-static and high-strain rate compression have been analyzed and discussed in the Z-transform domain. The results indicate that the stress-strain curves are rate sensitive, and tensile modulus, maximum tensile stress and corresponding tensile strain are also sensitive to the strain rate. The tensile modulus, maximum tensile stress of the 3D braided composites are linearly increased with the strain rate. With increasing of the strain rate (from 0.001/s to 2100/s), the tensile failure of the 3D braided composite specimens has a tendency of transition from ductile failure to brittle failure. The magnitude response and phase response is very different in quasi-static loading with that in high-strain rate loading. The 3D braided composite system is more stable at high strain rate than quasi-static loading.

Role of Deformable Fine Spinel Particles in High-Strain-Rate Superplastic Flow of Tetragonal ZrO2

2004 ◽  
Vol 821 ◽  
Author(s):  
Koji Morita ◽  
Keijiro Hiraga ◽  
Byung-Nam Kim ◽  
Yoshio Sakka
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Flow Behavior ◽  
Grain Boundary Sliding ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
Stress Concentrations ◽  
Tensile Direction

AbstractThe role of MgAl2O4 spinel particle dispersion in high-strain-rate superplasticity (HSRS) of tetragonal ZrO2 was examined by characterizing microstructural changes during deformation. The dispersed spinel particles elongate with strain along tensile direction and the elongation tends to be pronounced with increasing strain rate. In the elongated spinel particles, intragranular dislocations lying along the elongated direction were observed, suggesting that the elongation relates to the dislocation motion. The flow behavior characterized by a stress exponent of ≈ 2.0 suggests that grain boundary sliding (GBS) is the predominant flow mechanism. The dislocation-induced plasticity in the spinel particles may assist the relaxation of stress concentrations exerted by GBS, leading to HSRS in tetragonal ZrO2.

Structure-Property Relationship in a Haynes® 242TM Alloy Subjected to Long-Term Exposure at 650°C

2012 ◽  
Vol 186 ◽  
pp. 156-159 ◽  
Author(s):  
Elżbieta Stępniowska ◽  
Stanisław Dymek
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Tensile Testing ◽  
Nominal Composition ◽  
Structure Property ◽  
Strengthening Phase ◽  
Nickel Based Superalloy ◽  
Structure Property Relationship ◽  
New Phase

This paper characterizes the microstructure and mechanical properties of the nickel-based superalloy with the nominal composition Ni–25Mo–8Cr (wt.%) after long-term annealing (4000, 6000 and 8000 h) at 650°C. The microstructure was characterized by TEM and SEM. Mechanical properties were measured trough tensile testing. The microstructure, composed initially of a dispersive Ni2(Mo,Cr) strengthening phase in a Ni-based solid solution, decomposed during annealing into a mixture of intermetallic (Ni3Mo- and Ni4Mo-type) phases and recrystallized Mo-lean Ni-based solid solution. The dominant new phase was a plate-shaped Ni3Mo-type phase. Regions adjacent to the plates of the Ni3Mo phase are recrystallized and free from the Ni2(Mo,Cr) strengthening phase.

An Investigation of Microstructure Inhomogeneity in Waspaloy Subjected to Plane Strain Compression Testing

2007 ◽  
Vol 558-559 ◽  
pp. 589-594 ◽  
Author(s):  
M.J. Thomas ◽  
Bradley P. Wynne ◽  
Eric J. Palmiere ◽  
Ken P. Mingard ◽  
Bryan Roebuck
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Plane Strain ◽  
High Strain ◽  
Plane Strain Compression ◽  
Strain Rates ◽  
Nickel Based Superalloy ◽  
Nominal Strain ◽  
Plane Strain Compression Test ◽  
Low Strain Rate

An assessment of the inhomogeneity of microstructure generated within plane strain compression test specimens has been performed using the nickel based superalloy, Waspaloy. Two variables were investigated: the effect of strain rate and the effect of friction at the tool/specimen interface. Tests were performed at 1040°C at nominal strain rates of 0.01 and 1 s-1 with and without a glass based lubricant. At the low strain rate the microstructure was relatively homogeneous regardless of the friction conditions. At the high strain rate there was significant microstructure variation from surface to mid plane which was further exaggerated by increased friction. Quantification of the inhomogeneity, however, is non-trivial in this alloy due to the complicated recrystallisation behaviour it exhibits and difficulty in differentiating between recrystallised and non-recrystallised grains.

scholarly journals Effect of Fiber Blending Ratio on the Tensile Properties of Steel Fiber Hybrid Reinforced Cementitious Composites under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4504
Author(s):  
Minjae Son ◽  
Gyuyong Kim ◽  
Hongseop Kim ◽  
Sangkyu Lee ◽  
Yaechan Lee ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Synergistic Effect ◽  
Strain Rate ◽  
Tensile Properties ◽  
High Performance ◽  
Steel Fiber ◽  
High Strain ◽  
Strain Rates ◽  
Cementitious Composite ◽  
Hybrid Fiber

In this study, a high-performance hybrid fiber-reinforced cementitious composite (HP-HFRCC) was prepared, by mixing hooked steel fiber (HSF) and smooth steel fiber (SSF) at different blending ratios, to evaluate the synergistic effect of the blending ratio between HSF and SSF and the strain rate on the tensile properties of HP-HFRCC. The experimental results showed that the micro- and macrocrack control capacities of HP-HFRCC varied depending on the blending ratio and strain rate, and the requirement for deriving the appropriate blending ratio was confirmed. Among the HP-HFRCC specimens, the specimen mixed with HSF 1.0 vol.% and SSF 1.0 vol.% (H1.0S1.0) exhibited a significant increase in the synergistic effect on the tensile properties at the high strain rate, as SSF controlled the microcracks and HSF controlled the macrocracks. Consequently, it exhibited the highest strain rate sensitivities of tensile strength, strain capacity, and peak toughness among the specimens evaluated in this study.

High Strain Rate Tensile Properties of AISI Type 304 Stainless Steel

1973 ◽  
Vol 95 (3) ◽  
pp. 182-185 ◽  
Author(s):  
J. M. Steichen
Keyword(s):  
Stainless Steel ◽  
High Strain Rate ◽  
Strain Rate ◽  
Tensile Properties ◽  
High Strain ◽  
304 Stainless Steel ◽  
Aisi Type ◽  
Type 304 ◽  
Type 304 Stainless Steel ◽  
Strength And Ductility

The high strain rate tensile properties of solution annealed Type 304 stainless steel have been determined experimentally. Tests were performed at strain rates ranging from 3 × 10−5 to 1 × 102 in./in./sec at temperatures from 600 to 1600 deg F. At temperatures to 1000 deg F, the strength and ductility are largely insensitive to variations in strain rate, whereas at temperatures from 1200 to 1600 deg F, significant increases in both strength and ductility are observed with increasing strain rate.

A Creep Model for Solder Alloys

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Yongchang Lee ◽  
Cemal Basaran
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Diffusion Processes ◽  
Dislocation Motion ◽  
Creep Model ◽  
Solder Alloys ◽  
Creep Models ◽  
And Diffusion ◽  
Cycling Loading

Demand for long-term reliability of electronic packaging has lead to a large number of studies on viscoplastic behavior of solder alloys. Various creep models for solder alloys have been proposed. They range from purely empirical to mechanism based models where dislocation motion and diffusion processes are taken into account. In this study, most commonly used creep models are compared with the test data and implemented in ABAQUS to compare their performance in cycling loading. Finally, a new creep model is proposed that combines best features of many models. It is also shown that, while two creep models may describe the same material stress–strain rate curves equally well, they may yield very different results when utilized for cycling loading. One interesting observation of this study is that the stress exponent, n., also depends on the grain size.

scholarly journals Influence of Hot Deformation and Precipitates on the Recrystallization of Nb-V-Ti Free-Cutting Steel

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1587
Author(s):  
Yang Yang ◽  
Xian-Ming Zhao ◽  
Chun-Yu Dong ◽  
Xiao-Yu Zhao
Keyword(s):  
Grain Boundary ◽  
High Strain Rate ◽  
Strain Rate ◽  
Hot Deformation ◽  
High Strain ◽  
Boundary Migration ◽  
Great Influence ◽  
Material Model ◽  
Dislocation Motion ◽  
Cutting Steel

Nb, V, and Ti were added to free-cutting steel to improve its mechanical properties by means of precipitation strengthening and fine grain strengthening. The process parameters during the hot deformation of Nb-V-Ti free-cutting steel were studied at strain rates of 0.01–10 s−1 and temperatures of 850–1250 °C. The isothermal compression test results showed that the temperature rise at low deformation temperature and high strain rate has a great influence on the softening of the steel. The processing maps at strains of 0.3–0.6 were established based on a dynamic material model (DMM). When the strain was 0.6, the optimum hot-working window was at a temperature in the range of 1150–1250 °C and at a strain rate in the range of 0.01–0.1 s−1. The instable regions were mainly located at low temperature and high strain rate. The instable characteristics included the mixed grains around the MnS phase, flow localization, and intense deformation. In general, the existence of MnS leads to a decrease in the toughness of the steel. The MnS phase was easy to be broken when the compression tested at a lower temperature, e.g., 850 °C and at a higher strain rate, e.g., 10 s−1; its morphology changed from a long-rod shape to a discontinuous shape, and then, to a dot-like shape with the decrease in temperature from 1250 to 850 °C and the increase in strain rate from 0.01 to 10 s−1. The nucleation mechanism of this steel was grain boundary bulging. The size of fine (Nb,Ti) (C,N) precipitates is less than 10 nm, inhibiting austenite recrystallization and leading to austenite strengthening during hot deformation at 850 °C. Moreover, the dislocation motion and grain boundary migration were greatly inhibited by the Ti-rich(C,N) and MnS throughout the entire hot deformation process.

scholarly journals High Strain Rate Tensile Properties of Annealed 2 1/4 Cr-1 Mo Steel

1976 ◽  
Vol 98 (4) ◽  
pp. 361-368 ◽  
Author(s):  
R. L. Klueh ◽  
R. E. Oakes
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
High Strain ◽  
Total Elongation ◽  
Major Effect ◽  
Dynamic Strain

The high strain rate tensile properties of annealed 2 1/4 Cr-1 Mo steel were determined and the tensile behavior from 25 to 566°C and strain rates of 2.67 × 10−6 to 144/s were described. Above 0.1/s at 25°C, both the yield stress and the ultimate tensile strength increased rapidly with increasing strain rate. As the temperature was increased, a dynamic strain aging peak appeared in the ultimate tensile strength-temperature curves. The peak height was a maximum at about 350°C and 2.67 × 10−6/s. With increasing strain rate, a peak of decreased height occurred at progressively higher temperatures. The major effect of strain rate on ductility occurred at elevated temperatures, where a decrease in strain rate caused an increase in total elongation and reduction in area.

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