Influence of heat treatment on the microstructure and mechanical properties of TC17 Titanium Alloy

Wang Min,Yao Zekun,Nin Yongquan,Fan Ya,Guo Hongzhen,Huang Darong,F Vollertsen,T.A Dean,S.J Yuan,Y Qin

doi:10.1051/matecconf/201819007002

Wang Min, Yao Zekun + Show 8 more

Open Access

https://doi.org/10.1051/matecconf/201819007002

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Abstract

The influence of heat treatment on the microstructure and mechanical properties of TC17 titanium alloy was investigated by changing holding time before forging and aging temperature after β-forging. A better heat treatment mechanism was chosen according to its working requirements. The results showed that the holding time and aging temperature had a significant influence on microstructures and mechanical properties of TC17 alloy. With the increase of holding time before forging in the single β phase region, the original β grain size enlarge, the strength and fracture toughness decrease, and the plasticity increases. The size of lamellar α-phase bundles enlarge with the rise of aging temperature after β-forging, the orientated relationship becomes simple, and the content of β-transformation increases. And the plasticity and fracture toughness of the alloy increase, the strength and hardness decreases. The fracture toughness is better under the heat treatment mechanism at 873°C/2h +918°C/64min before forging, 800°C/4h,WC+660°C /8h AC after forging, with the high and low cycle fatigue properties meet the technical requirements.

Highlights

Titanium alloys have been widely used in aircraft, aircraft engines and other fields owing to their high strength and toughness, relatively low density, excellent creep and corrosion resistance[1,2]
TC17 (Ti-5Al-2Sn2Zr-4Mo-4Cr) of near β-titanium alloy belongs to medium temperature and high strength titanium alloy
The fracture toughness decreases with the increase of strength of high strength titanium alloy, and the strengthening of alloy properties is constrained by both plasticity and toughness at a certain strength level

Summary

Introduction

Titanium alloys have been widely used in aircraft, aircraft engines and other fields owing to their high strength and toughness, relatively low density, excellent creep and corrosion resistance[1,2]. The fracture toughness decreases with the increase of strength of high strength titanium alloy, and the strengthening of alloy properties is constrained by both plasticity and toughness at a certain strength level. Along with the application of damage tolerance design idea in titanium alloy, the fracture toughness of titanium alloy has been attracted more and more attention and research. Titanium alloy β forging has a series of advantages, such as good plasticity, low deformation resistance, high production efficiency and long service life of the forging equipment [6]. TC17 titanium alloy is taken as the research subject in this paper, studying the effect of heat treatment on the microstructure and mechanical properties of TC17 titanium alloy by changing holding time before forging and aging temperature after β-forging, and optimal heat treatment system has been selected according to the service requirements of TC17 titanium alloy, which provides experimental and theoretical basis for actual practice

Materials and procedures

Results and discussion

The effect of heat treatment after forging on mechanical properties

Conclusion