J. Mater. Sci. Technol. ›› 2012, Vol. 28 ›› Issue (3): 221-228.

• Reviews • 上一篇    下一篇

Coarsening kinetics of γ' Precipitates in the dendritic regions of a Ni3Al base alloy

Hosein1,M. Soltanieh2,3,Saeed Rastegari2,3   

  1. 1. Iran ubiversity of science and technology
    2. Iran university of science and technology
    3.
  • 收稿日期:2011-04-18 修回日期:2011-09-09 出版日期:2012-03-31 发布日期:2012-03-31
  • 通讯作者: Hosein

Coarsening Kinetics of γ′ Precipitates in Dendritic Regions of a Ni3Al Base Alloy

H.B. Motejadded, M. Soltanieh, S. Rastegari   

  1. School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran
  • Received:2011-04-18 Revised:2011-09-09 Online:2012-03-31 Published:2012-03-31
  • Contact: Hosein BannaMotejadded Emrooz

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摘要： Coarsening behavior of γ' precipitates in the dendritic regions of a Ni3Al base alloy containing chromium, molybdenum, zirconium and boron was investigated. Annealing treatment was performed up to 50 hours at 900, 1000 and 1100 oC. The alloy was produced with vacuum-arc remelting technique. Results show that coarsening of the γ' precipitates in this complex alloy containing high volume fractions of γ' phase follows Lifshitz-Slyozov-Wagner (LSW) theory. Coarsening activation energy of the γ' precipitates was evaluated to be about 253.5 kJ.mol-1 which shows that the growth phenomenon is controlled by volume diffusion of aluminum. With an innovative approach, diffusion coefficient of the solute element(s) and also the interfacial energy between γ' precipitates and γ (matrix) was estimated at 900, 1000 and 1100 oC. Accordingly, the interfacial energies at 900, 1000 and 1100 oC are 4.49±1.48, 2.08±0.69 and 0.98±0.32 mJ.m-2, respectively. Also the diffusivities of solute element(s) at these temperatures are 3.41±1.08, 30±9.5 and 145.15±45.85 (10-15 m2.sec-1), respectively.

Abstract: Coarsening behavior of γ′ precipitates in the dendritic regions of a Ni3Al base alloy containing chromium, molybdenum, zirconium and boron was investigated. Annealing treatment was performed up to 50 h at 900, 1000 and 1100 °C. The alloy was produced by vacuum-arc remelting technique. Results show that coarsening of the γ′ precipitates in this complex alloy containing high volume fractions of γ′ phase follows Lifshitz-Slyozov-Wagner (LSW) theory. Coarsening activation energy of the γ′ precipitates was evaluated to be about 253.5 kJ?mol-1 which shows that the growth phenomenon is controlled by volume diffusion of aluminum. With an innovative approach, diffusion coefficient of the solute element(s) and the interfacial energy between γ′ precipitates and γ (matrix) were estimated at 900, 1000 and 1100 °C. Accordingly, the interfacial energies at 900, 1000 and 1100 °C are 4.49±1.48, 2.08±0.69 and 0.98±0.32 mJ?m-2, respectively. Also the diffusivities of solute element(s) at these temperatures are 3.41±1.08, 30±9.5 and 145.15±45.85 (10-15 m2?s-1), respectively.

Key words: Ni3Al base intermetallic, Coarsening kinetics, Activation energy