scholarly journals The effects of solution treatment on the microstructure of the cast Ni-based IN100 superalloy

10.30544/78 ◽  
2015 ◽  
Vol 21 (3) ◽  
pp. 167-182 ◽  
Author(s):  
A. Jafari ◽  
S. M. Abbasi ◽  
A. Rahimi ◽  
M. Morakabati ◽  
M. Seifollahi

In this research, the effects of the partial, full and partial + full solution heat treatments followed by aging at 900 °C for 10 h, on the microstructure of cast Ni-based IN100 superalloy were assessed. It has been found that, the alloy in the partial + full solution treated condition had the optimal combination of γ’ morphology, volume fraction and size. In this condition, the alloy possesses a cubic primary γ’with an average size of 470±10nm and 45% volume fraction. Discrete M23C6 and M6C carbides were formed at the grain boundaries and the morphology of the cubic MC carbide was changed to the spherical shape. In addition, the volume fraction of γ’/γ eutectic phase dropped to half of its value, compared to the as-cast alloy. During partial solution treatment followed by aging, discrete carbides were formed at the grain boundaries. This treatment without full solutioning was not an effective method to provide an optimal volume fraction and arrangement of γ’ and MC carbides morphology. Full solutioning alone, changed the cubic morphology of the primary γ’ and the blocky MC carbides to the spherical shape.

2014 ◽  
Vol 937 ◽  
pp. 182-186
Author(s):  
Quan An Li ◽  
Lei Lei Chen ◽  
Wen Chuang Liu ◽  
Xing Yuan Zhang ◽  
Hui Zhen Jiang

The influence of the solution treatment (at the temperature of 500-520°C for 4-12 h) on microstructures and mechanical properties of Mg-Gd-Y-Zr alloy was investigated by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Vickers hardness measurement. The as-cast alloy contains a microstructure consisting of α-Mg matrix, Mg5Gd phase and Mg24Y5phase. With increasing solution temperature and time, the quantity of the primary particles (Mg5Gd and Mg24Y5) in the alloy continually decreased, and the degree of recrystallization gradually increased, which result in the gradual decrease of the Vickers hardness of the solution-treated alloys.


2010 ◽  
Vol 17 (3) ◽  
pp. 350-361
Author(s):  
C.J. Boehlert ◽  
S.C. Longanbach

AbstractUdimet 188 was subjected to thermomechanical processing (TMP) in an attempt to understand the effects of cold-rolling deformation on the microstructure and tensile-creep behavior. Commercially available sheet was cold rolled to varying amounts of deformation (between 5–35% reduction in sheet thickness) followed by a solution treatment at 1,464 K (1,191°C) for 1 h and subsequent air cooling. This sequence was repeated four times to induce a high-volume fraction of low-energy grain boundaries. The resultant microstructure was characterized using electron backscattered diffraction. The effect of the TMP treatment on the high-temperature [1,033–1,088 K (760–815°C)] creep behavior was evaluated. The measured creep stress exponents (6.0–6.8) suggested that dislocation creep was dominant at 1,033 K (760°C) for stresses ranging between 100–220 MPa. For stresses ranging between 25–100 MPa at 1,033 K (760°C), the stress exponents (2.3–2.8) suggested grain boundary sliding was dominant. A significant amount of grain boundary cracking was observed both on the surface and subsurface of deformed samples. To assess the mechanisms of crack nucleation, in situ scanning electron microscopy was performed during the elevated-temperature tensile-creep deformation. Cracking occurred preferentially along general high-angle grain boundaries (GHAB) and less than 25% of the cracks were found on low-angle grain boundaries (LAB) and coincident site lattice boundaries (CSLB). Creep rupture experiments were performed at T = 1,088 K (815°C) and σ = 165 MPa and the greatest average time-to-rupture was exhibited by the TMP sheet with the greatest fraction of LAB+CSLB. However, a clear correlation was not exhibited between the grain boundary character distribution and the minimum creep rates. The findings of this work suggest that although grain boundary engineering may be possible for this alloy, simply relating the fraction of grain boundary types to the creep resistance is not sufficient.


2013 ◽  
Vol 747-748 ◽  
pp. 320-326 ◽  
Author(s):  
Wen Xiang Wu ◽  
Li Jin ◽  
Jie Dong ◽  
Zhen Yan Zhang ◽  
Wen Jiang Ding

The hot deformation behaviors and microstructural evolution of Mg-3.0Nd-0.2Zn-0.4Zr (wt. %, NZ30K) alloy were investigated by means of the isothermal hot compression tests at temperatures of 350-500 °C with strain rates of 0.001, 0.01, 0.1 and 1s-1. The results showed that the flow stress increased to a peak and then decreased which showed a dynamic flow softening. The flow stress behavior was described by the hyperbolic sine constitutive equation with an average activation energy of 193.8 kJ/mol. The average size of dynamically recrystallized grains of hot deformed NZ30K alloy was reduced by increasing the strain rate and/or decreasing the deformation temperature. A large amount of fine particles precipitated in the grains interior and at the grain boundaries when heated to the compression temperatures and soaked for 5min below 450 °C. However, the volume fraction of particles decreased significantly when soaked for 5 min at 500 °C, and the coarse particles precipitated mainly at the grain boundaries. Hot deformation at the temperature of 500 °C around and at the strain rate range of 0.1s-1 was desirable for NZ30K alloy.


2013 ◽  
Vol 747-748 ◽  
pp. 398-403 ◽  
Author(s):  
Dong Qing Zhao ◽  
Xu Guang Dong ◽  
Xin En Zhang ◽  
An Jiang Gao ◽  
Ji Xue Zhou ◽  
...  

The microstructures and tensile properties of as-cast, solution-treated and aged Mg-4Zn-2Sn-2Al (wt.%) alloy have been investigated. The microstructure of the as-cast alloy consists of α-Mg, Mg2Sn and Mg32(Al,Zn)49 phases. The yield tensile strength and the ultimate tensile strength of the as-cast alloy are 87.7 MPa and 241.3 MPa, respectively, and the elongation reaches to 18.8% showing excellent ductility. After solution treatment, all of the Mg32(Al,Zn)49 phase and the majority of Mg2Sn particles have dissolved into the matrix. During aging process, Mg2Sn phase precipitates from the α-Mg supersaturated solid solution. With the precipitation strengthening of Mg2Sn phase, the yield tensile strength and the ultimate tensile strength of the alloy increase to 112.5 MPa and 280.4 MPa, respectively, while, the elongation decreases to 12%.


2020 ◽  
Vol 12 (9) ◽  
pp. 1399-1402
Author(s):  
Ji-Hyun Kim ◽  
Min-Su Kim ◽  
Tae-Hyun Nam

Ti–xNi–12Cu (at%) (x = 39, 40) alloys were prepared and then their transformation behavior and microstructures were investigated after solution treatment at various temperatures by means of scanning electron microscopy, energy dispersive X-ray spectroscopy, and differential scanning calorimetry. Matrix (B2), Ti2 (Ni, Cu) and Ti(Ni, Cu)2 phases were observed in all specimens except the TiNi39Cu12 alloy solution treated at 1373 K in which matrix (B2) and Ti2 (Ni, Cu) were observed. Volume fraction of Ti(Ni, Cu)2 phase decreased with increasing solution treatment temperature. All specimens showed the B2–B19 martensitic transformation behavior. Transformation temperatures and hysteresis decreased with increasing solution treatment temperature, which was ascribed to the decrease in the volume fraction of Ti(Ni, Cu)2 phase resulting in the increase in Ni content of matrix.


2006 ◽  
Vol 503-504 ◽  
pp. 107-112 ◽  
Author(s):  
Bert Verlinden ◽  
M. Popović

Two Aluminium alloys, type AA5182 and AA5182+1.2wt% Cu, have been studied. The second alloy in solution treated condition is 18% stronger than the first one. During ageing at 150°C or 200°C it shows a characteristic fast increase in yield strength during the first minutes of ageing, followed by a 'plateau'. Both materials have been deformed in an ECAP die (4 and 8 passes) at 200°C and the microstructure, hardness and mechanical properties in compression at room temperature have been investigated. Although in none of the two materials a true sub-micron grain size was obtained at 200°C, a fair combination of strength and strain hardening was observed. The AA5182+Cu alloy, when ECAP’ed after a solution treatment and quenching, shows an increase in strength of about 20% compared to the AA5182 reference alloy. A post-ECAP annealing at 200°C does not lead to a further increase in hardness or strength. An analysis of the substructure and the mechanical properties during ECAP led to the conclusion that the precipitates formed during ECAP at 200°C do not directly contribute to the higher strength of alloy AA5182+Cu, but they contribute indirectly by slowing down the recovery.


2007 ◽  
Vol 353-358 ◽  
pp. 357-360
Author(s):  
Gui Qing Wang ◽  
Zhong Kui Zhao ◽  
Yan Liu

The present work was performed on Al11Si3Cu0.35Mg samples cast in a permanent mold preheated to 200 °C. The tensile properties for varies solution treated samples aged at 200 °C for 6 h were examined in order to study the influence of solution temperature on the alloy properties. The dissolution of copper-containing phases and the incipient melting were analyzed for cast samples solution treated in the temperature range 500~520 °C for 8 h followed by quenching in water. The influence of the incipient melting on mechanical properties has been discussed.


2013 ◽  
Vol 747-748 ◽  
pp. 238-244 ◽  
Author(s):  
Xin Su ◽  
De Jiang Li ◽  
Yan Cai Xie ◽  
Xiao Qin Zeng ◽  
Wen Jiang Ding

The effect of Sm content (2, 4, 6, 8wt.%) on the microstructures and mechanic properties of gravity casting Mg-xSm-0.4Zn-0.3Zr alloys were investigated. The results showed that the cast alloy mainly consists of α-Mg matrix and Mg41Sm5 phase distributed at the grain boundaries, and the amount of the second phase increased with the rise of Sm content. After the solution treatment (T4), the second phase disappeared, however small amount of cuboid-like phase were found inside the grain, and its volume fraction also increases with the rise of Sm content. It is found in the age hardening curves of the alloys at 175, 200, and 225 °C that the alloys with various components almost showed the same trend of age hardening. While the higher the Sm content, the harder the alloy. With the Sm content increases, the yield strength (TYS) of cast alloys (F state) were obviously improved, however the tensile strength (UTS) became lower because of the quick drop of the elongation. The elongations of solid solution (T4) and aging (T6) alloy became lower, while the yield strength and tensile strength increased at first and then decreased. The optimized component is Mg-4Sm-0.4Zn-0.3Zr, which the mechanic properties at T6 state are: TYS=131MPa; UTS=261MPa; δ=6.8%.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 625
Author(s):  
Yoko Yamabe-Mitarai ◽  
Syuji Kuroda ◽  
Norie Motohashi ◽  
Takanobu Hiroto ◽  
Akira Ishida ◽  
...  

The Ti compressor disks of aviation jet engines are produced by forging. Their microstructure, which depends on the forging conditions, strongly affects their mechanical properties. In this study, changes in the microstructure of Ti-17 alloy as a result of different solution-treatment (ST) temperatures and the related tensile yield strengths were investigated to elucidate the correlation between the ST temperature, microstructure, and yield strength. Ti-17 alloys ingots were isothermally forged at 800 °C and solution-treated at 750, 800, and 850 °C. The microstructure and yield strength were investigated for samples subjected to different ST temperatures. The primary α phase formed during the ST, and the secondary α phase formed during the aging treatment at 620 °C. The yield strength increased with increasing volume fraction of the primary α phase and increased further upon formation of the secondary α phase during the tensile test at room temperature. The correlation of the primary and secondary α phases with yield strength was clarified for tensile properties at room temperature, 450, and 600 °C. An equation to predict the yield strength was constructed using the volume fraction of the primary and secondary α phases.


2020 ◽  
Vol 321 ◽  
pp. 04018
Author(s):  
Z. Huvelin ◽  
C. Gouroglian ◽  
N. Horézana ◽  
S. Naka

The effect of Tungsten (W), Tantalum (Ta) and simultaneous addition of Germanium (Ge) and Silicon (Si) on the microstructure evolution, tensile and creep properties of the near-alpha alloy Ti-5.7Al-3.9Sn-3.7Zr-0.7Nb-0.5Mo-0.35Si-0.05C have been investigated at high temperatures up to 650°C. Microstructural characterizations following solution treatment at 1050°C for 2 hours with oil quenching and aging treatment at 700°C for 2 hours followed by air cooling, highlighted that the additions of refractory elements such as W and Ta led to a decrease of both the volume fraction of the primary alpha phase (ap) and its average size. Tensile tests performed up to 650°C revealed a significant improvement in tensile strength with additions of W and Ta, even though a decrease of ductility has been also detected. Creep tests carried out at 600°C under a constant stress of 200 MPa pointed out that, refractory elements, Ge and Si have a beneficial effect on both primary and steady-state creep strain rates.


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