Provide personal solutions to such problems for your reference:

I will find a product within the applicable scope of TC 18, and take the demand intensity and working temperature of the product as the experimental values in the first stage, and then make adjustments according to the experimental results.

For example, I want to use TG6 as the engine material, and the engine must meet the conditions of 800℃ and 500 MPa, so I set 800℃ and 500 MPa as the experimental conditions. Reference suggestion

You can follow the relevant experimental methods.

I. Standard of applicable test methods for creep endurance testing machine

1. national standard GB/T2039- 1997 "test method for tensile creep and durability of metals"

2. Aviation industry standard HB5 195-96 "High temperature tensile fatigue test method for metals"

Generally, it is incorrect to control the creep strain below 0.4%. I read a paper that said so, but I'm sorry I can't remember which one.

Test method for influence of microstructure on creep behavior of near α TG6 titanium alloy at high temperature;

The creep properties of TG6 titanium alloy were tested on RDW30 100 electronic endurance tester at 600℃ and 200MPa. In the experiment, a cylindrical specimen is used, the diameter of the working part is 16 mm, and the gauge distance is 50 mm The relationship curve between strain and time is recorded by automatic data acquisition system, and the steady creep rate (minimum creep rate) is calculated according to the slope of the curve. In Philip Quanta? The microstructure of TG6 titanium alloy was observed and analyzed by 600 scanning electron microscope.

I hope it will be helpful to your research and wish you success.

Provide several recently read journal articles for reference only.

Relationship between microstructure and properties of TC 18 titanium alloy and heat treatment system, Material Research,No. 1, 2009.

Abstract: The effects of three temperature stages of two-stage annealing heat treatment system on the properties and microstructure of TC 18 titanium alloy were studied by using the orthogonal design method of three factors and three levels. The influence of heat treatment temperature change on the comprehensive properties of the alloy was quantitatively analyzed. The results show that increasing the middle temperature and decreasing the low temperature can improve the strength of the alloy, and decreasing the high temperature and increasing the low temperature can improve the plasticity of the alloy. Reducing the middle and high temperature can improve the impact toughness of the alloy. Microstructure analysis shows that the strength of TC 18 titanium alloy is mainly controlled by the total amount of untransformed β structure and secondary αs phase generated on it, and the content and shape of secondary αs phase. The plasticity of the alloy is controlled by the shape of primary αp phase and the number and shape of secondary αs phase. The impact toughness of the alloy is controlled by the content and shape of primary αp phase.

Effect of TC 18 Hot Pressing Parameters on Rheological Stress and Microstructure of Titanium Alloy Engineering 20 10No. 1

Author: Sha Li Hongen

Abstract: the effects of strain rate and deformation temperature on the deformation resistance and microstructure of titanium alloy TC 18 were systematically studied through thermal simulation experiments at 700 ~ 950℃ and strain rate of 0.00 1 ~ (- 1). The results show that increasing the deformation temperature or decreasing the strain rate can significantly reduce TC 65438. Compared with the single-phase region, the deformation resistance in the two-phase region is more sensitive to the change of temperature. When α+β zone is deformed, both α phase and β phase participate in the deformation, the spherical primary α is slightly elongated along the deformation direction, and β phase forms a fibrous structure along the metal flow direction. When the deformation temperature is higher than the β phase transition point, the β phase is fibrous along the metal flow direction, and the recrystallization equiaxed β grains can be observed at 950℃.

Effects of Two Typical Heat Treatment Processes on Microstructure and Properties of TC 18 Titanium Alloy: Progress of Titanium Industry, No.6, 2009

Author: Lu Zhengping Peng Yang Jianchao Mao Xiaonan

Abstract: Two typical heat treatment systems, two-stage annealing and solid solution strengthening, were used to systematically study the effect of the whole heat treatment process on the microstructure and properties of TC 18 titanium alloy forgings through mechanical properties test, microstructure analysis and XRD phase analysis. The results show that the two-stage annealing structure not only meets the strong-plastic matching, but also the fracture toughness KIC value can reach 75 Mpa? m 1/2； Although the structure after solution strengthening heat treatment has higher strength than the former, the plastic loss is greater and the fracture toughness KIC value is lower.

Tensile plasticity of equiaxed microstructure and full lamellar microstructure of BT 18y titanium alloy at room temperature.

Author: Yang Yang

Abstract: The tensile properties of deformed Ti-6.9Al-3.6Zr-2.7Sn-0.7Mo-0.6Nb-0.21Si (BT18Y) titanium alloy bars after solution treatment at two temperatures were tested. The relationship between tensile plasticity and microstructure of the alloy at room temperature was studied by metallographic microscope, transmission electron microscope and scanning electron microscope. The results show that the material after air cooling at 920℃ for 2 h has fine-grained equiaxed structure, good coordination between grains during deformation, excellent tensile properties at room temperature, especially plastic protrusion. The material air-cooled at 65438 0020℃ for 2 h has a coarse lamellar structure of grain boundary α phase. During tensile deformation, it is required that adjacent grains and adjacent α beams in the grains coordinate with each other, which increases the resistance of plastic deformation, but the residual β phase keeps the material plastic. Multi-angle observation shows that the α beam is directional, and the beam with a small angle to the tensile axis has good tensile properties, and the β phase intermediate layer in the beam with a large angle to the tensile axis is the priority area for crack formation in the tensile process.

Research progress of BT22 titanium alloy and its heavy forgings Material Guide 20 10/0,24 (3)

Northwest Institute of Nonferrous Metals, Xi 'an, 7 100 16.

Author: Peng Province Mao Yafeng Zheng Ping Yang Jianchao Han

The application status of BT22 alloy and its modified alloy at home and abroad is reviewed, and the forging process and heat treatment process of BT22 alloy are introduced. The results show that BT22 alloy can be forged many times in the temperature range below β _ turn 15 ~ 50℃, and the thermal deformation is not less than 60% each time. By strictly controlling the deformation rate and final forging temperature, forgings with uniform structure and fine grains can be prepared. After two-stage integral heat treatment, the best match of strength, plasticity and toughness can be obtained. According to the domestic research status, the problems to be solved urgently in the preparation of BT22 alloy heavy forgings and the future research and development direction are pointed out.

Brief introduction of hot working process of BT22 titanium alloy, 38, 2009 (14)

(School of Metallurgical Engineering, Xi University of Architecture and Technology, Xi, Shaanxi, 710055; Northwest Nonferrous Metals Research Institute, Titanium Alloy Research Institute, xi 'an, Shaanxi, 7 100 16)

Author: Mayor Mao Xiaonan Yang Guanjun Niu Rongrong

The development and application of a new type of high strength and high toughness titanium alloy (BT22) are introduced. The alloy composition, mechanical properties, physical properties, alloy phase transformation and heat treatment process are listed.

Analysis of solution cooling characteristics of BT22 titanium alloy: rare metal materials and engineering: 20 10 02

Xi University of Architecture and Technology; Northwest Institute of Nonferrous Metals;

Wu Xiaodong Peng Ge Yang Guanjun Mao Xiaonan Zhou Wei Feng Baoxiang

Using ANSYS finite element analysis software, the temperature field of BT22 titanium alloy in cooling stage after solution heat treatment was simulated, and the equivalent diagram of temperature distribution of heat-treated workpiece during cooling process was drawn. The inhomogeneity of temperature drop is analyzed from two angles: temperature-time curve and temperature curve of different parts in the workpiece. By comparing the measured curve with the simulated curve, it is found that the relative error between them is 2% ~ 5%. At the same time, the measured cooling curve is divided into three stages: rapid cooling stage, gentle cooling stage and slow cooling stage, and the reasons for its formation are analyzed.

Effect of Microstructure on Stress Controlled Low Cycle Fatigue Properties of TC 18 Titanium Alloy, Materials Engineering, No.5, 2009

Author: Rusha Ai Xue Feng Kang Tun, Yvonne Wang

Abstract: The effects of two typical microstructures, flake and basket, on the low cycle fatigue life of TC 18 titanium alloy under different stress amplitudes were studied. The results show that the low cycle fatigue life of TC 18 titanium alloy is insensitive to the change of microstructure. Under the same stress amplitude, the fatigue life of twin-crystal structure and sheet-like structure is basically the same. The low cycle fatigue life n of TC 18 titanium alloy depends on the stress amplitude, and σmax has a logarithmic relationship with n.

Study on creep behavior of flaky TiAl alloys with different W content Chen Wenhao Southwest Jiaotong University 2009

In this paper, the mechanical properties of three as-cast TiAl alloys (0W alloy, 1 w alloy, 1.4w alloy) with full lamellar structure with tungsten content of 0,1and1.4w alloy were studied at 700℃, atmospheric atmosphere and different stress conditions. The microstructure changes of three alloys before and after creep were analyzed in detail. It is found that among the three as-cast TiAl alloys with W content of 0 at. %，65，438+0 at。 % and 65,438+0.4 at. %, 65,438+0 at alloy. % w has the best creep performance, while 65,438+0.4 at. % w has the worst creep performance. Grain size has a decisive influence on the creep resistance of TiAl alloy with full lamellar structure. The refinement of grain size will obviously reduce the creep properties of the alloy. W can stabilize γ and a2 platelets. After creep 1000 hours, the γ and a2 lamellae of the two tungsten-containing alloys remain stable, while the a2 lamellae without tungsten alloy decompose in parallel, and the a2 lamellae content decreases. At the same time, it is also found that a certain amount of B2+ω segregation phase is located at the grain boundary, which is beneficial to the creep properties of the full-lamellar TiAl alloy. The intragranular creep mechanisms of the three alloys are dislocation slip and creep. After creep, a large number of dislocations appear in γ lamellae of the alloy, which will move to the center of γ lamellae and entangle with each other, but the dislocations cannot move across a2 lamellae.

Study on high temperature creep behavior of Ti-44Al-5Nb-0.85W-0.85B alloy

Huang Wenze

Key Laboratory of Advanced Materials Technology, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 6 1003 1.

Abstract: Fine-grained as-cast TiAl alloy Ti-44al-5nb-0.85w-0.85b (at. %) has been studied. Before creep, the alloy was subjected to hot isostatic pressing at 1260℃ and 1340℃ respectively, and two different microstructures were obtained: after hot isostatic pressing at 1260℃, a large number of B2+ω precipitates were precipitated at the lath grain boundaries, while in the α single-phase region (1. Constant stress tensile creep experiments were carried out at 700℃ and 150 ~ 300 MPa, and the effects of B2+ω segregation on the creep properties of the alloy under different stresses were studied and discussed. The results show that after long-term creep 1000 hours at 700℃ and 300MPa stress, the alloys in the two states are still in the steady-state creep stage without fracture. All-lath alloy containing W shows good creep properties. It is also found that the microstructure containing B2+ω segregation phase has better creep performance than that without this segregation phase, and the creep control mechanism has changed between 200 ~ 300 MPa and 300 MPa. The microstructure was observed in detail by scanning electron microscope and transmission electron microscope. The results show that the thick γ lath contains high dislocation density, and dislocation plugging is found at the tip of the lath, the anti-domain boundary and the α2/γ interface. α2+γ lath shows good stability. Occasionally, coarse α2 laths are decomposed in parallel, and only a few γ laths are deformation twins, and there is no lath fracture spheroidization. The results show that the massive B2+ω segregation phase is completely eliminated after hot isostatic pressing at 1340℃, but the ordered phase reappears on the grain boundary after creep.

Journal of University of Science and Technology Beijing on high temperature deformation behavior of powder metallurgy TiAl-based alloys: 20 10 09

Lu Xin Wang Shuchao in Hongmin District Xuanhui

The high temperature compressive properties and deformation behavior of powder metallurgy Ti-47.5Al-2.5V- 1.0Cr alloy were studied at the deformation temperature of 600 ~ 1050℃ and the strain rate of 0.002 ~ 0.2s- 1.05℃. The results show that the alloy is compressed at high temperature. With the increase of deformation temperature and the decrease of strain rate, the yield strength decreases and the plasticity tends to increase. During plastic deformation at high temperature, the Arrhenius relation modified by hyperbolic sine function can be well satisfied among peak flow stress, strain rate and deformation temperature, which shows that deformation is controlled by heating. In the range of 800 ~1050℃/0.002 ~ 0.2s-1

Low Cycle Fatigue Behavior of TC2 1 Alloy under Stress Control and Strain Control, Rare Metal Materials and Engineering, No.2, 2009.

Abstract: The low cycle fatigue behavior of TC2 1 alloy under strain control and stress control was studied. The experimental temperature is room temperature, the cyclic strain ratio and stress ratio are both 0. 1, and the load waveform is triangular wave. The results show that at the initial stage of strain fatigue, TC2 1 alloy softens rapidly under cyclic tensile stress and hardens rapidly under cyclic compressive stress, and the softening and hardening rate decreases with the cyclic process. The back stress has little effect, and the friction stress is always changing, and the change of cyclic stress is related to the friction stress. The low cycle fatigue results of stress control show that the cyclic creep of TC2 1 alloy is obvious, which is related to stress, and friction stress is the main factor affecting cyclic creep.

High temperature mechanical behavior and deformation mechanism of Ti-47Al-2W-0.5Si creep resistant alloy: 200 1 08

Zhou Guo Jianting v. Lupinc M.Maldini

The mechanical behavior and deformation mechanism of Ti-47Al-2W-0.5Si casting alloy were studied. The results show that the yield strength at room temperature and high temperature and the creep strength at 650℃ of the alloy exceed the specific yield strength and creep strength of IN7 13LC nickel-based superalloy, showing excellent mechanical properties at medium temperature. During the creep process, the minimum creep rate of the alloy increases with the increase of load and temperature. It can be described by the creep equation ε m = a () 10 exp (-). Dislocation spreads at the interface and entangles and blocks in α2/γ lamellae, which leads to the decrease of the initial creep strain rate of the alloy. When the dislocation motion is blocked, the internal stress can be relieved by twins. Twinning and shearing may occur in the first stage of creep. Under the action of high temperature stress, α 2 lamellae become coarse and undergo phase transformation.