Indexed by:Journal Papers

Date of Publication:2020-04-01

Journal:ULTRASONICS

Included Journals:PubMed、EI、SCIE

Volume:103

Page Number:106090

ISSN No.:0041-624X

Key Words:Coarse-grained austenite; Fatigue damage; Electron backscatter diffraction; Ultrasonic; Grain scale

Abstract:The elastic anisotropy and heterogeneity effects of coarse-grained austenite on ultrasonic propagation significantly undermine the effectiveness of ultrasonic property-based fatigue damage evaluation. A discrete method based on electron backscatter diffraction (EBSD) was proposed to decouple the effects between coarse-grained structure and fatigue damage. An orientation-based damage index, local misorientation (M-L), was extracted and macroscopic and microscopic plastic deformations were characterized. The evolution of ultrasonic attenuation coefficient Delta alpha was established with Delta M-L in grain scale. Approximate downward parabolas was observed, and the peak value of Delta alpha in < 1 1 1 > orientation was found to be larger and more sensitive to the cyclic damage than that of < 0 0 1 > and < 0 1 1 >. The influences of the heterogeneous substructure and surface roughness were discussed respectively.