航空材料学报

2014, 34(4): .

[Abstract](1205) [PDF 3530KB](86)

Abstract:

High Temperature Titanium Alloys：Status and Perspective

WANG Qing-jiang, LIU Jian-rong, YANG Rui

2014, 34(4): 1-26.

[Abstract](2681) [PDF 9215KB](296)

Abstract:
The history of solid solution strengthened high temperature titanium alloys was briefly reviewed and those alloys developed in the UK, USA and Russia were compared. Three kinds of alloys, Ti55, Ti60 and Ti65, covering the temperature range of 550-650℃, and related welding technology were introduced. Suggestions for perfecting the systematics of high temperature titanium alloys in China are made based on an overview of the status quo. Six key issues that should be tackled in the near future are identified and discussed.

Alloy Design and Application Expectation of A New Generation 600℃ High Temperature Titanium Alloy

CAI Jian-ming, CAO Chun-xiao

2014, 34(4): 27-36.

[Abstract](1750) [PDF 1186KB](224)

Abstract:
The developments of advanced aeroengine and ultrasonic aircraft have impending demands for 600℃ high temperature titanium alloy which is heat-resistant and has a relatively low density. By substituting steel or superalloys, 600℃ high temperature titanium alloy can be manufactured into high pressure compressor discs, blades, blisks and casing of aeroengines, structural components and airframe skins of aircraft. As a result, the weight of aeroengine and aircraft can be reduced, thus the thrust-weight ratio of aeroengine, flight speed and flexibility of aircraft can be improved markedly. The design of 600℃ high temperature titanium alloy is restricted by the intrinsic contradiction between creep and thermal stability. To maximize the creep resistance, meanwhile keeping a combination of good fracture toughness, ductility and thermal stability, a new generation 600℃ titanium alloy TA29 of Ti-Al-Sn-Zr-Nb-Ta-Si-C system was designed and developed based on the Equivalent Design Criterion(EDC) and Diffusion Theory to meet the rigid design demand. TA29 alloy may seek a wide scope of application, such as high temperature components in advanced aeroengines and ultrasonic aircraft. The creep-fatigue-environment interaction, micro-textured region, surface integrality, residual stress and service properties of TA29 alloy and its components may be the research emphases in the future.

Development and Future of Chinese Titanium Industry and Technology

CHANG Hui, ZHOU Lian, WANG Xiang-dong

2014, 34(4): 37-43.

[Abstract](1631) [PDF 1626KB](173)

Abstract:
Chinese titanium industry has been got remarkable progress after the development for 60 years by 2014. Based on brief introduction of Chinese titanium industry, the progress of titanium extractions, plastic deformation theories and technologies, phase transformation and microstructure control as well as near net forming technologies was reviewed. Finally, the future of the Chinese titanium industry and technologies was pointed, including the application technology research (especially titanium alloy used in marine), cost efficient technologies, fundamental research and property data collection, computer simulation on alloy design and deformation process.

Recent Research and Development of Titanium Alloys for Aviation Application in China

ZHU Zhi-shou

2014, 34(4): 44-50.

[Abstract](2080) [PDF 2885KB](418)

Abstract:
The output capacity of titanium sponge and mill products in China has ranked the first in the world. Compared with the developed countries, the aviation application level and amount of high performance titanium alloys in China still far lags behind that of developed countries. Based on the summary of research situation in titanium alloys technology,the technology maturity promotion approaches of new type and key titanium alloys is given by means of the optimization of synthetical properties, the variety and complete specifications, the expansion of the application scales, the sophistication of standard and specifications, the sufficiency of testing and verification, etc. And it is also very necessary to establish an aviation-oriented titanium alloys system with Chinese characteristics, to meet the design requirements of high performance, low cost, and a raised amount of consumption and application level of titanium alloys.

Current Situation and Development of New Titanium Alloys Invented in China

ZHAO Yong-qing, GE Peng

2014, 34(4): 51-61.

[Abstract](1912) [PDF 2549KB](204)

Abstract:
Titanium alloys are widely used because of their excellent comprehensive properties. The research and development of new titanium alloys in recent 20 years in China, including high strength alloys, damage tolerance alloys, high temperature alloys, corrosion resistant alloys, alloys used for ship-building, low cost alloys, medical alloys and so on were reviewed. The research and development of titanium alloys in China changed from early imitation to independent research. The new titanium alloys invented in China are over 30 kinds. The important development trend of titanium is low cost, short technological process, near net shaping and so on.

Application of Finite Element Method in Hot Forming of Titanium Alloy Aircraft Engine Blades

BAI Qian, LIN Jianguo

2014, 34(4): 62-71.

[Abstract](1913) [PDF 1678KB](209)

Abstract:
Titanium alloys are widely used in the precision hot forged engine blades for aircraft. Applications of hot forging for engine blades of titanium alloys are discussed.Finite element (FE) modelling has been extensively used to ensure a better understanding of the hot forming process. This review paper provides an overview of current research development on hot forging FE modelling for engine blades: material constitutive modelling, heat transfer definition and friction characteristics are among the most important aspects to ensure an accurate FE prediction. It is concluded that FE modelling studies and analysis are needed to create predictive physically-based models which should be in good agreement with reliable experimental results when investigating the effects of many parameters on hot forging of titanium alloys.

Advances in Microstructure Control during Isothermal Forming of Ti-Alloy Large Complex Components by Near-β Local Forging

YANG He, SUN Zhi-chao, FAN Xiao-guang, GAO Peng-fei, WU Chuan

2014, 34(4): 72-82.

[Abstract](1497) [PDF 7621KB](109)

Abstract:
High-performance large complex components of Ti-alloy have become the inevitable choice for aerospace high-end equipment to achieve large carrying capacity, low energy consumption, long life. The precision plastic forming of these large complex Ti-alloy components faces two large challenges, such as how to improve manufacturing capacity and how to implement an integrated regulation of forming and performance. Isothermal near- forging by local loading provides an advanced technology for the forming of such components. However, due to the particularity of forming process, complexity of component in structure and sensitivity of Ti-alloy microstructure to forming way and conditions, the microstructure control and how to get tri-modal structure with excellent performance become a key problem to be solved urgently for research, development and application of this forming technology. This paper presents analysis and state of the art from aspects such as microstructure evolutionary mechanisms of Ti-alloy during multi-pass isothermal local loading forming, microstructural uniformity control of different loading regions and transition regions, formation of tri-modal structure and parameters optimization of isothermal local loading.

Ignition Resistance Performance and Its Mechanism of TC11 Titanium Alloy for Aero-Engine

MI Guang-bao, CAO Chun-xiao, HUANG Xu, CAO Jing-xia, WANG Bao

2014, 34(4): 83-91.

[Abstract](1602) [PDF 5731KB](151)

Abstract:
The effect of friction contact pressure P and oxygen concentration c0 of premixed air flow on the ignition resistance of TC11 titanium alloy was studied by frictional ignition test. The relationship P-c0 quantitatively describing the ignition resistance of TC11 was established and the microscopic mechanism of ignition and ignition resistance of TC11 was provided by in-situ observation, SEM and EDS, etc. The results show that the relationship P-c0 of TC11 obeys parabolic rule. When Pincreases from 0.05MPa to 0.25MPa, the c0 required for ignition decreases by about 32.5%. The c0 of TC11 ignition is 20% higher than that of TC4 at least, i.e., the ignition resistance performance of TC11 is obviously higher than that of TC4. The violent sparks appeared during friction process, and the origin of ignition was located at the micro-bump which has a fresh surface. During ignition, four distinct zones form, including combustion zone, fusion zone, heat-affected zone and transitional zone. The diffusion rate of Ti from heat-affected zone to fusion zone is lowered by the Ti-based solid solution which is rich in aluminum and molybdenum, and thus the reaction between titanium and oxygen in the combustion zone is restricted. Besides, the solution of a large amount of oxygen in the fusion zone inhibits the diffusion of oxygen to the heat-affected zone. As a result, the ignition resistance of micro-bump is improved.

Research Progress on Application Technique of Ti-V-Cr Burn Resistant Titanium Alloys

CAO Jing-xia, HUANG Xu, MI Guang-bao, SHA Ai-xue, WANG Bao

2014, 34(4): 92-97.

[Abstract](1734) [PDF 1858KB](175)

Abstract:
Burn-resistant titanium alloy is developed for preventing or minimizing the titanium fire in aero-engine. Burn-resistant titanium alloys with different V containing in Ti-V-Cr alloying system are broadly researched in recent 10 years. They are Ti40 and TF550 with service temperatures of 500℃ and 550℃ respectively. Many results were achieved in the techniques of Ti-V-Cr burn resistant alloys' large scale ingot melting, ingot extruding, billet forging and ring rolling. Through the frictional ignition testing, a method based on P-c0 relationship curve was established to quantitatively describing the fireproof characteristic of titanium alloy. Results show that the fireproof characteristic of Ti40 alloy is similar to TF550 alloy. Ti40 and TF550 have their own advantages by overall considerations of the cost of raw materials, comprehensive mechanical properties and manufacturing progress.

Preparation and Performance Characteristics for Multilayered Ti-Al Intermetallics Alloys

SUN Yan-bo, MA Feng-mei, XIAO Wen-long, MA Chao-li

2014, 34(4): 98-111.

[Abstract](1776) [PDF 4654KB](155)

Abstract:
Mulitlayered microstructures constituted Ti-Al intermetallics and titanium not only retain the high temperature strength of Ti-Al intermetallics, but also possess the high toughness at room temperature, which get a lot of attention from the researchers. Author reviews two methods of preparing the multilayered Ti-Al intermetallics toughened by titanium, namely foils-foils metallurgy and physical vapor deposition process. The microstructures and properties of the different multilayered materials was presented. The advantages and disadvantages of various techniques also were described. The development and potential application of this kind of materials are also proposed. In the future, it would be still important to prepare the multilayered materials with more appropriate structures and excellent performance by adjusting the preparation process.

Progress of Deformed TiAl Alloys

CHEN Yu-yong, CUI Ning, KONG Fan-tao

2014, 34(4): 112-118.

[Abstract](1588) [PDF 1799KB](178)

Abstract:
Deformed TiAl alloys, the most promising high temperature structure materials due to their low density, high strength and good oxidation resistance, can be used to replace heavier Ni-based alloys applied in power system of aerospace industries. Great improvement was made after years of research. Progresses in alloying, smelting, hot deformation (forging, hot extrusion and rolling), powder metallurgy and heat treatment of TiAl alloys were reviewed. The problems existed in researches were also discussed. Finally, the prospective future development of deformed TiAl alloys was summarized. The hot workability and room temperature ductility of TiAl alloy need to be further improved. Alloying, hot deformation and numerical simulation are future research directions. The ultimate goal is engineering applications.

Key Technologies and Research Advances of Wrought TiAl Alloys

ZHANG Ji

2014, 34(4): 119-125.

[Abstract](1595) [PDF 2304KB](148)

Abstract:
The key technologies and research advances of wrought TiAl alloys were reviewed. The micro-alloying process with Ni was identified to improve the hot workability remarkably and also enchance the dynamic recrystallization during hot deformation. Meanwhile, lowering Al content introduces high temperature phase that impedes the grains' growth above the transus temperatures, so the fully lamellar microstructures is refined. The Ti-46Al-2.5V-1.0Cr-0.3Ni (atomic percentage) alloy modified accordingly shows a prominent hot workability as preheated up to 1200-1250℃. After extrusion, the refined fully lamellar microstructures was produced by the heat treatment at 1350℃ for 5mins and followed with air-cooling and exhibited excellent mechanical properties.

Progress on Discontinuously Reinforced Titanium Matrix Composites

HUANG Lu-jun, GENG Lin

2014, 34(4): 126-138.

[Abstract](1746) [PDF 3750KB](164)

Abstract:
Discontinuously reinforced titanium matrix composites (DRTMCs) exhibited extensive application due to their superior characteristics of low density, high temperature durability, high strength and good deformability. Recently, researchers pay more attention to DRTMCs again,because of urgently needs of new ultra-high-speed aircraft and next-generation high thrust weight ratio aeroengine. Recent research progress of fabrication methods, selection of reinforcement and matrix, reinforcement distribution, subsequent deformation and heat treatment and mechanical properties were reviewed. In addition, the problems in the present research are also pointed out and then the further research directions in future are proposed. In order to obtain further development, a series of DRTMCs with high modulus, high abrasion resistance, high strength and toughness and high temperature durability should be prepared respectively. Moreover, gradient surface or coating with higher abrasion resistance or higher oxidation resistance should be designed and fabricated in order to enhance their service lifetime. Fabricating tiny components, intricate components and controlling the reinforcement distribution by 3D printing technology should be involved in future work. The components with large size, intricate shape and different materials of DRTMCs can be obtained by proper welding technologies.

Progress on in-situ Discontinuously Reinforced Titanium Matrix Composites

LU Wei-jie, GUO Xiang-long, WANG Li-qiang, QIN Ji-ning, ZHANG Di

2014, 34(4): 139-146.

[Abstract](1778) [PDF 2102KB](168)

Abstract:
The synthesis reactions, microstructures and mechanical properties of in situ discontinuously reinforced titanium matrix composites were introduced in detail. Moreover, the future research field for titanium matrix composites is the development of new reinforcement reinforced titanium matrix composites, and the study of the addition law of strengthening effects of hybrid reinforced titanium matrix composites are pointed.

Cold Working Plastic Deformation for TiNbTaZr Titanium Alloy

WANG Yu-hui, ZHANG Hui, ZHANG Wang-feng, YAN Meng-qi, LI Ye

2014, 34(4): 147-152.

[Abstract](1448) [PDF 2167KB](134)

Abstract:
The cold working plasticity and its mechanism of Ti35Nb2Ta3Zr0.3O alloy were investigated based on mechanical property test, collaborated with optical microscopy, XRD, SEM and TEM analysis techniques. The results show that low work hardening, even no work hardening, occurs at the initial deformation for Ti35Nb2Ta3Zr0.3O alloy. After deformation ratio exceeded 50%, grain size became refined significantly and plasticity was enhanced. It is concluded that the addition of about 35% Nb can decrease the stacking fault energy of the alloy, which results in the partially inhibition of sliding and climbing of the dislocations. However, the plastic deformation is improved by twinning. During large deformation, multi order twinning happened. It is the reason that the unique plasticity of Ti35Nb2Ta3Zr0.3O alloy is caused by twining and sliding together due to twinning induced plasticity (TWIP) and the low stacking fault energy.

2014 Vol. 34, No. 4