Influences of Solution Temperatures on Microstructure and Mechanical Properties of near α Titanium Alloy

2021 ◽  
Vol 1035 ◽  
pp. 89-95
Author(s):  
Chao Tan ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Xiao Zhao Ma ◽  
Zi An Yang

A new type of Ti-Al-Sn-Zr-Mo-Si series high temperature titanium alloy was prepared by a water-cooled copper crucible vacuum induction melting method, and its phase transition point was determined by differential thermal analysis to be Tβ = 1017 °C. The influences of solution temperature on the microstructures and mechanical properties of the as-forged high temperature titanium alloy were studied. XRD results illustrated that the phase composition of the alloy after different heat treatments was mainly α phase and β phase. The microstructures showed that with the increase of the solution temperature, the content of the primary α phase gradually reduced, the β transformation structure increased by degrees, then, the number and size of secondary α phase increased obviously. The tensile results at room temperature (RT) illustrated that as the solution temperature increased, the strength of the alloy gradually increased, and the plasticity decreased slightly. The results of tensile test at 650 °C illustrated that the strength of the alloy enhanced with the increase of solution temperature, the plasticity decreased first and then increased, when the solution temperature increased to 1000 °C, the alloy had the best comprehensive mechanical properties, the tensile strength reached 714.01 MPa and the elongation was 8.48 %. Based on the room temperature and high temperature properties of the alloy, the best heat treatment process is finally determined as: 1000 °C/1 h/AC+650 °C/6 h/AC.

2020 ◽  
Vol 993 ◽  
pp. 208-216
Author(s):  
Ya Peng Cui ◽  
Zi Yong Chen ◽  
Xiao Zhao Ma ◽  
Ying Ying Liu ◽  
Zhi Lei Xiang ◽  
...  

The microstructures and mechanical properties of a new type near α high temperature titanium alloy Ti-6.5Al-2.5Sn-9Zr-0.5Mo-0.25Si-1Nb-1W-0.3Re (wt. %) (denoted as TA6.5) were investigated. It was observed that the microstructure of forged TA6.5 mainly consisted of deformed lamellar α phase, small amount of equiaxed α phase, and residual β phase, exhibiting high strength and comparatively low elongation. Three different heat treatments processes were performed on forged TA6.5. The results showed that all heat treated alloys displayed high tensile strengths, and the values of strength parameters were almost unchanged with the increasing solution temperature, ascribing to the combination effects of decreasing primary α phase and increasing contents and widths of secondary α phase and lamellas. The tensile elongations of heat treated alloys tested at 650 °C decreased slightly with the increasing solution temperature, which is due to the increased width of secondary α lamellas and the generation of coarse grain boundary α phase. TA6.5 treated in the process of 990 °C/1 h/AC+700 °C/4 h/AC exhibited excellent comprehensive mechanical properties, i.e. the ultimate tensile strength of 829 MPa, yield strength of 707 MPa and elongation of 18.73% respectively.


2012 ◽  
Vol 535-537 ◽  
pp. 924-927
Author(s):  
Wang Tao ◽  
Mi Lin Zhang ◽  
Shu Jin Zhao ◽  
Chun Mei Song ◽  
Cheng Ju

Mg-8.5Li-1Al-1Ce alloys were prepared with vacuum induction melting method. Uniaxial rolling deformation of alloys was obtained by two-roll milling. The effect of rolling deformation was studied on the microstructure and mechanical properties of Mg-8.5Li-1Al-1Ce. The results show that the microstructure morphologies of α-phase, β-phase and Al2Ce-phase go through different changes under different rolling percentages, and the mechanical properties are improved with increasing deformation. Besides the basal slip system, the prism and pyramidal slip systems are also activated in α(Mg) phase, with all the slip systems in β(Li) phase being uniformly activated.


2018 ◽  
Vol 910 ◽  
pp. 155-160 ◽  
Author(s):  
An Jin Liu ◽  
Lin Wang ◽  
Hua Xiang Dai

Microstructure evolution and compression property of Ti-10V-2Fe-3Al titanium alloy were studied in this paper. Solution treatments were performed at temperature ranging from 710°C to 830°C and some followed by aging treatment. Ti-10V-2Fe-3Al alloys with α+β phase show higher mechanical properties compared with single β phase alloy. With the increase of solution temperature, the content of equiaxed α phase decrease. Consequently, the strength of the alloy increases while the plasticity drops down. The highest yield strength value of 1668 MPa was obtained in the sample treated by 770°C solution treated for 2 hours then water quenched and followed by 520°C aging for 8 hours then air cooled. The stress induced martensite α'' phase appeared after SHPB dynamic compression in the sample solution treated at 830°C.


1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.


2021 ◽  
Vol 1035 ◽  
pp. 305-311
Author(s):  
Qing Shan Liu ◽  
Bo Long Li ◽  
Tong Bo Wang ◽  
Cong Cong Wang ◽  
Peng Qi ◽  
...  

A new type of near α high temperature titanium alloy of Ti-Al-Sn-Zr-Mo-Si-Er was studied. The samples with different primary α phase content were prepared by solid solution at 950 °C/1 h—1010 °C/1 h. The multi-step hot compression experiments were carried out by Gleeble-3500 in a sequence of upper region of α + β phase, then followed by lower region of α + β phase. The effects of primary α phase content and deformation temperature on the microstructure of the alloy were studied by means of true stress-strain curve and optical microscope. The results show that the content of primary α phase gradually decreases from 45.4% at 950°C to 0% at 1010°C. As the deformation temperature decreases from 940°C to 900°C, the content of α phase increases gradually from 65% to 94%, which is changed from dynamic recrystallization to deformed structure elongated along RD direction. It is found that the arrangement of α phase along RD direction is the longest at 920°C. With the increase of the deformation temperature in the multi-step high temperature region from 970°C to 990°C, the width of deformed α phase decreases from 3.64 μm at 970°C to 2.71 μm at 990°C. The optimized microstructure is composed of 20% primary α phase arranged along RD direction. This process has a certain potential in the process of hot deformation of the alloy. Key words: high temperature titanium alloy, primary α phase, multi-step hot deformation


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.


2013 ◽  
Vol 477-478 ◽  
pp. 1288-1292
Author(s):  
Bo Long Li ◽  
Tong Liu ◽  
Jie Yuan ◽  
Zuo Ren Nie

The high strength and low cost Ti-Fe based alloy was produced by double vacuum induction melting method followed by hot deformation. The microstructure has been investigated by Optical Microscopy, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The microstructure of as-forged alloy is composed of α and β phase without the precipitation of TiFe intermetallic compound. The Ti-Fe-Al alloys show good comprehensive mechanical properties, demonstrating ultimate tensile strength of 1100MPa and elongation above10%. The results indicate the Fe is a good candidate for solution strengthening and simultaneously increasing ductility in titanium alloys. Effect of the Fe and Al elements on the microstructure and mechanical properties have been discussed.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1185
Author(s):  
Zhimin Wang ◽  
Lulu Sun ◽  
Wenchao Ke ◽  
Zhi Zeng ◽  
Wei Yao ◽  
...  

The joining of high-temperature titanium alloy is attracting much attention in aerospace applications. However, the defects are easily formed during laser welding of titanium alloys, which weakens the joint mechanical properties. In this work, laser oscillating welding was applied to join TC31 high-temperature titanium alloy. The weld appearance, microstructure and mechanical properties of the laser welds were investigated. The results show that sound joints were formed by using laser oscillating welding method, and a large amount of martensite was presented in the welds. High mechanical properties were achieved, which was approaching to (or even equaled) the strength of the base material. The joints exhibited a tensile strength of up to 1200 ± 10 MPa at room temperature and 638 ± 6 MPa at 923 K. Laser oscillating welding is beneficial to the repression of porosity for welding high-temperature titanium alloy.


2018 ◽  
Vol 913 ◽  
pp. 109-117 ◽  
Author(s):  
Qing Yun Zhao ◽  
Si Rui Cheng ◽  
Li Dong Wang ◽  
Li Min Dong ◽  
Feng Lei Liu

The effects of heat treatment on microstructure and mechanical properties of Ti-38644 alloy were investigated by scanning electron microscope (SEM) and transmission electron microscopy (TEM) as well as uniaxial tensile test. The results show that when the solution temperature is lower than 845°C, the microstructure of Ti-38644 alloy is equiaxed β phase with the grain size of 20μm, and the tensile strength is about 960MPa. As raising solution temperature to 860°C, the grain size of Ti-38644 alloy increases to 100μm and the tensile strength decreased to 870MPa. There are a large number of secondary α phase precipitated from the grain boundaries and within grain of β phase undergoing aging treatment. Secondary α phase coarsens with increasing the aging temperature, leading to the decrease of tensile strength. After solution treatment at 815°C for 1.5h, water quenching plus aging at 520°C for 10h, air cooling, Ti-38644 alloy shows a better mechanical property with the tensile strength 1330MPa, elongation and reduction of area 10% and 45% respectively.


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