Open AccessEffect of thermal relaxation on residual stress and microstructure in the near-surface layers of dual shot peened Inconel 625
Author(s) -
Lihui Wu,
Chuanhai Jiang
Publication year - 2018
Publication title -
advances in mechanical engineering/advances in mechanical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.318
H-Index - 40
eISSN - 1687-8140
pISSN - 1687-8132
DOI - 10.1177/1687814018800530
Subject(s) - materials science , residual stress , microstructure , inconel , peening , relaxation (psychology) , isothermal process , composite material , stress relaxation , inconel 625 , metallurgy , diffraction , shot peening , stress (linguistics) , alloy , thermodynamics , optics , linguistics , philosophy , psychology , social psychology , creep , physics
Thermal relaxation behavior of residual stress and microstructure in the near-surface layers of dual shot peened Inconel alloy 625 was investigated by X-ray diffraction method. Residual stress on the top surface layer was significantly relaxed in the first 15 min at the elevated temperatures of 500°C, 600°C, and 700°C. However, there was still high maximum compressive residual stress in subsurface layers. The relaxation behavior of residual stress has contributed to the thermally activated process. The activation enthalpy Δ H and m were calculated according to the Zener–Wert–Avrami method, the values of which were 1.59 eV and 0.4934, respectively. Microstructural evaluation revealed that it was slightly changed in the near-surface layers after various isothermal treatments. Accordingly, high level of compressive residual stress and dislocation density resulted in the retained mechanical properties of dual shot peened Inconel 625, which was discussed based on the relaxation of microstructure and microhardness.