Hot deformation behavior of A286 superalloy with two different smelting processes

doi:10.13251/j.issn.0254-6051.2021.12.010

Abstract

Abstract: In order to investigate the hot deformation behavior of A286 superalloy with two smelting processes of VIM+VAR (vacuum induction melting+vacuum arc remelting) and EAF+LF+VAR (electric arc furnace+ladle furnace+vacuum arc remelting), hot compression tests were carried out on a Gleeble-3800 hot simulation test machine at temperatures ranging from 950 to 1150 ℃ and strain rates ranging from 0.01 to 10 s^-1. The Arrhenius constitutive equations of the A286 alloy are established based on the true stress-true strain curves and work hardening rate curves modified by friction and adiabatic heating. The hot deformation activation energies of the VIM+VAR alloy and the EAF+LF+VAR alloy are determined to be 358.15 and 372.54 kJ·mol^-1, respectively. A new dynamic recrystallization model is established by introducing the dynamic recrystallization velocity parameter k_v with critical strain and 50% dynamic recrystallization volume fraction strain. Prasad criterion is used to draw the hot processing maps at 0.2, 0.5 and 0.9 strain of the A286 alloy prepared by the two smelting processes. Combined with the microstructure analysis, the optimal hot working conditions of the VIM+VAR alloy is 1050-1100 ℃, 0.01-1 s^-1 and 1100-1150 ℃, 0.1-10 s^-1, while that of the EAF+LF+VAR alloy is 1050-1100 ℃, 0.01-1 s^-1 and 1100-1150 ℃, 0.1-3 s^-1. It is concluded that the VIM+VAR alloy has a wider hot-working range and its hot-working performance is better than that of the EAF+LF+VAR alloy.

Key words: A286 superalloy, hot deformation, constitutive equation, dynamic recrystallization, hot processing map

CLC Number:

TF764

Deng Shanshan, Sun Yongqing, Jiang Yehua, Liu Zhenbao, Liang Jianxiong, Wang Changjun. Hot deformation behavior of A286 superalloy with two different smelting processes[J]. Heat Treatment of Metals, 2021, 46(12): 61-71.

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