scholarly journals Correlation between Solution Treatment Temperature, MicroStructure, and Yield Strength of Forged Ti-17 Alloys

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.

2022 ◽  
Vol 60 (1) ◽  
pp. 83-93
Author(s):  
Young-We Kim ◽  
Yong-Hee Jo ◽  
Yun-Soo Lee ◽  
Hyoung-Wook Kim ◽  
Je-In Lee

The effects of dissolution of the η′ phase by solution treatment on the mechanical properties of A7075-T6 alloy were investigated. Immediately after solution treatment of the T6 sheet at 450 oC or higher, elongation significantly increased and dissolution of the η′ phase occurred. η′ is the main hardening phase. After natural-aging, GPI, which is coherent with the aluminum matrix, was formed and strength increased. When bake hardening after natural-aging was performed, the yield strength slightly increased due to partial dissolution of the GPI and re-precipitation of the η′ phase. In contrast, after solution treatment at 400 oC, there was less elongation increase due to the precipitation of the coarse η phase at grain boundaries and low dissolution of the η′ phase. In addition, when bake hardening after natural-aging was performed, the yield strength decreased due to insufficient GPI, which is the nucleation site of the η′ phase. To promote reprecipitation of the η′ phase, the solution treatment temperature was set to a level that would increase solubility. As a result, the yield strength was significantly increased through re-precipitation of a large number of fine and uniform η′ phase. In addition, to increase the effect of dissolution, a pre-aging treatment was introduced and the bake hardenability can be improved after dissolution.


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.


2020 ◽  
Vol 321 ◽  
pp. 11015
Author(s):  
M. Niinomi ◽  
T. Akahori ◽  
M. Nakai ◽  
Y. Koizumi ◽  
A. Chiba ◽  
...  

The microstructures, tensile properties, and fatigue lives of the forged Ti-17 using a 1500-ton forging simulator subjected to different solution treatments and a common aging treatment under both load- and strain-controlled conditions to evaluate high cycle fatigue and low cycle fatigue lives, respectively were examined. Then, the tensile properties, microstructures, and relationships between fatigue lives and the microstructural factors were discussed. The fatigue limit under load-controlled conditions increases with increasing solution treatment temperature up to 1143 K, which is in the (α + β) region. However, it decreases with further increase in the solution treatment temperature to 1203 K in the b region. The fatigue ratio at fatigue limit is increasing with decreasing solution treatment temperature, namely increasing the volume fraction of the primary α phase, and it relates well qualitatively with the volume fraction of the primary α phase when the solution treatment temperature is less than the b transus temperature. The fatigue life under strain-controlled conditions to evaluate the low cycle fatigue life increases with decreasing solution treatment temperature, namely increasing the volume fraction of the primary α phase. The fatigue life under strain-controlled conditions to evaluate the low cycle fatigue life relates well quantitatively with the tensile true strain at breaking of the specimen and the volume fraction of the primary α phase for each total strain range.


2013 ◽  
Vol 747-748 ◽  
pp. 932-936 ◽  
Author(s):  
Xin Nan Wang ◽  
Yue Fei ◽  
Xiao Hu Zhou ◽  
Zhi Shou Zhu ◽  
Jun Li ◽  
...  

The evolution regularities of microstructure and property of a new metastable β titanium alloy with different solution treatment and aging treatment were studied using optical microscope (OM), scanning electron microscopy (SEM) and tensile test. The results show that, the volume fraction of primary α phase decreases and globularization of α phase occurs with the increasing aging temperature from 540 to 580 and solution treated temperature from 800 to 820. When the solution treated temperature is 820, the acicular secondary α phase precipitates along β grain boundary. The strength of the investigated alloy increases and the ductility decreases with the solution treated temperature increasing. While the strength of the investigated alloy increases and the ductility decreases with the aging temperature decreasing.


2015 ◽  
Vol 661 ◽  
pp. 98-104 ◽  
Author(s):  
Kuang-Jau Fann ◽  
Pao Min Huang

Because of being in possession of shape memory effect and superelasticity, Ni-Ti shape memory alloys have earned more intense gaze on the next generation applications. Conventionally, Ni-Ti shape memory alloys are manufactured by hot forming and constraint aging, which need a capital-intensive investment. To have a cost benefit getting rid of plenty of die sets, this study is aimed to form Ni-Ti shape memory alloys at room temperature and to age them at elevated temperature without any die sets. In this study, starting with solution treatments at various temperatures, which served as annealing process, Ni-rich Ni-Ti shape memory alloy wires were bent by V-shaped punches in different curvatures at room temperature. Subsequently, the wires were aged at different temperatures to have shape memory effect. As a result, springback was found after withdrawing the bending punch and further after the aging treatment as well. A higher solution treatment temperature or a smaller bending radius leads to a smaller springback, while a higher aging treatment temperature made a larger springback. This springback may be compensated by bending the wires in further larger curvatures to keep the shape accuracy as designed. To explore the shape memory effect, a reverse bending test was performed. It shows that all bent wires after aging had a shape recovery rate above 96.3% on average.


2018 ◽  
Vol 939 ◽  
pp. 38-45 ◽  
Author(s):  
Risly Wijanarko ◽  
Irene Angela ◽  
Bondan Tiara Sofyan

Al 7xxx alloy is a heat treatable Al alloy with superior strength. Solution treatment in precipitation hardening sequence of the alloy has an important role to dissolve second phases and bring vacancies out to form precipitates in the ageing process. Another strengthening can be done by Ti addition as grain refiner. As cast alloy by squeeze casting was homogenized at 400 °C for 4 h. Solution treatment was conducted at 220, 420, and 490 °C, followed by rapid quenching. Subsequent ageing was conducted at 130 °C for 48 h. Characterization was performed by optical microscope, SEM-EDS (Scanning Electron Microscopy – Energy Dispersive Spectroscopy), Rockwell hardness testing, XRD (X-Ray Diffraction), and STA (Simultaneous Thermal Analysis). Ti added alloy showed rounder grains, lower hardness, and more reduction in second phase volume fraction along with increasing solution treatment temperature than those in alloys without Ti addition. Otherwise, the alloy final hardness was increasing and higher after the ageing process due to higher second phase dissolution which leads to more precipitates formed.


2020 ◽  
Vol 321 ◽  
pp. 11048
Author(s):  
Ren Yong ◽  
Yang Nan ◽  
Lei Jinwen ◽  
Li Shaoqiang ◽  
Du Yuxuan

The effects of primary α phase volume fraction on the tensile properties at 400℃ of TC4 titanium alloy was studied by different solution temperature(Tβ-(10~80)℃). The effects of the thick of secondary α phase on the tensile properties at 400℃ of TC4 titanium alloy was studied by different cooling speed after solution treatment (water quench, air cooling, furnace cooling). The results show that with the decrease of primary α phase, the tensile and yield strength increase up, but the ductility has a little change. The thick of secondary α phase increases with the deceases of cooling speed after solution treatment, highest tensile and yield strength by water quench, the tensile strength of air cooling and furnace cooling were basically the same, but the yield strength of furnace cooling was 40MPa lower than air cooling. Therefore, the influence of the primary α phase volume fraction on the tensile strength at 400℃ was particularly obvious, we can control solution treatment and cooling way in combination with different requirements.


2020 ◽  
Vol 1010 ◽  
pp. 21-27
Author(s):  
Noraziana Parimin ◽  
Esah Hamzah

The effect of solution treatment temperature on the microstructure, phase present and hardness on Fe-33Ni-19Cr alloy was study in this work. The Fe-33Ni-19Cr alloy was experienced a solution treatment process at six different temperatures which are 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C and 1200 °C for 3 hours soaking time followed by water quench. The average grain size was measured by using linear intercept methods ASTM E112. Microstructure of solution-treated Fe-33Ni-19Cr alloy was characterized by using optical microscope and scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) spectrometer. The phase present was analyzed using x-ray diffraction (XRD) technique. The Vickers hardness was used to measure the hardness of solution-treated Fe-33Ni-19Cr alloy. Increasing the solution treatment temperatures were increase the average grain size of solution-treated Fe-33Ni-19Cr alloy. In addition, all samples exhibited an equiaxed matrix grain with slight distribution of precipitates particles. The hardness of solution-treated Fe-33Ni-19Cr alloy was decrease as the solution treatment temperature increase.


2014 ◽  
Vol 783-786 ◽  
pp. 2423-2428 ◽  
Author(s):  
Hideki Hosoda ◽  
Kenta Kasuya ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Shuichi Miyazaki

In order to develop new β (bcc) Ti alloys, the Ti-Fe-Sn system was focused and phase constitution, microstructure, mechanical properties of Ti-5mol%Fe-6mol%Sn and Ti-6mol%Fe-3mol%Sn were clarified in addition to aging effect. It was estimated by differential scanning calorimetry (DSC) that α phase is formed at temperature from 773-779K and that β transus temperature is 1019K in both the alloys. X-ray diffraction analysis revealed that, in both alloys, β single phase is formed after the solution treatment (ST) at 1273K followed by water quenching, while α phase is formed after the aging at 773K and 873K for 3.6ks. The formation of α phase is also confirmed by optical microscopy. The volume fraction of α phase reaches to 90% in Ti-5Fe-6Sn and 80% in Ti-6Fe-3Sn after the aging at 873K for 3.6ks. The 0.2% proof stress was increased by aging at 873K from 550MPa to 650MPa in Ti-5Fe-6Sn and 500MPa to 690MPa in Ti-6Fe-3Sn. Besides, apparent Young’s modulus measured by dynamic mechanical analysis was raised by the aging treatment. These changes in the mechanical properties were discussed in connection with α phase precipitation.


2011 ◽  
Vol 695 ◽  
pp. 405-408 ◽  
Author(s):  
Ho Seob Yun ◽  
Joon Sik Park ◽  
Seong Uk An ◽  
Jeong Min Kim

It was observed that both primary and secondary gamma prime precipitates were more significantly influenced by the solid solution treatment temperature as compared to the following cooling rate. Single and duplex size precipitate distribution with different average size could be obtained through the appropriate solid solution and aging treatment. Micro-hardness test result indicated that single size distribution of gamma prime precipitates provides higher hardness than duplex size distribution.


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