Modeling and investigation for atomic diffusion and mechanical properties of TiAl/Ti 3 Al interface: temperature effect
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Modeling and investigation for atomic diffusion and mechanical properties of TiAl/Ti3Al interface: temperature effect Jinsong Chen1 · Wenjun Chen1 · Changhao Wang2 Received: 26 March 2020 / Accepted: 28 May 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The effect of temperature on the diffusivity and mechanical property of the TiAl/Ti3Al interface at nanoscale was investigated using molecular dynamics (MD). The diffusion mechanism is atomic self-diffusion in the TiAl or T i3Al blocks at the temperatures of 673 ~ 1273 K. However, self-diffusion and asymmetric counter-diffusion determine the diffusion process. The self-diffusion of atoms in the T i3Al block is much better than that in the TiAl block under the same temperature. The average atomic diffusive distance in the TiAl block is significantly farther than that in the T i3Al block owing to its lower melting point and greater numbers of slipping system. The yield strength of the joint after diffusion welding at the temperatures of 673 ~ 1373 K is about 1.2 GPa higher than that at 1473 K. The temperature has little effect on the mechanical properties of elastic modulus, yield strength, yield strain and flow stress of the diffusion joint at the temperatures of 673 ~ 1273 K. However, the elastic modulus, yield strength and flow stress decrease gradually with the increase in temperature at 1273 ~ 1473 K. Keywords γ-TiAl/α2-ti3al interface · Molecular dynamics · Atomic diffusion · Temperature · Mechanical properties
1 Introduction TiAl-based alloys containing γ-TiAl and α2-Ti3Al biphasic lamellar structures, which exhibit excellent comprehensive properties such as high specific strength, corrosion resistance and oxidation resistance are extensively applied to aerospace, national defense and navigation, electronic devices and transportation and other fields [1–3]. Generous researches have been carried out on the preparation of biphasic lamellar TiAl alloys (γ-TiAl and α2-Ti3Al) by severe plastic deformation process. Schillinger et al. [4] investigated that the textures of TiAl base alloy after hot rolling were mainly common dislocations, super dislocations and twinning, which had a significant influence on recrystallization and mechanical properties. Sun et al. [5] researched the effect of isothermal forging process on the mechanical properties and microstructures of TiAl-based alloys. It was * Wenjun Chen [email protected] 1
Institute of Physics and Electronic Engineering, Yibin University, Yibin 644000, Sichuan Province, People’s Republic of China
Chengdu Aeronautic Polytechnic, College of Aeronautic Engineering, Chengdu 610100, People’s Republic of China
2
found that the isothermal forging process could make TiAlbased alloys form α2/γ colonies, thus increasing the tensile strength and yield strength of about 80 MPa without sacrificing plasticity. Shen et al. [6, 7] fabricated TiAl/Ti3Al micro-laminated sheets with high strength by electron beam physical vapor deposition and hot isostatic pressing, which had good ten
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