Open AccessEffect of pre-deformation and artificial aging on fatigue life of 2198 Al-Li alloy
Author(s) -
Yue Zhang,
Juan Liang,
Huaguan Li,
Xiaohu Luo,
Yongmin Wang
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
ISSN - 2053-1591
DOI - 10.1088/2053-1591/ab83a6
Subject(s) - materials science , alloy , nucleation , deformation (meteorology) , metallurgy , precipitation , transmission electron microscopy , dislocation , scanning electron microscope , composite material , chemistry , nanotechnology , physics , organic chemistry , meteorology
The effects of pre-deformation and artificial aging on fatigue life of 2198 Al-Li alloy were explored to further reveal its fatigue behavior and improve the damage tolerance. Fatigue life was investigated on 2198-T3 alloy after pre-deformation and aging treatments. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the fracture morphology, precipitation behavior, fatigue crack initiation and propagation. Results indicated that T 1 (Al 2 CuLi) phase dominated the strengthening of 2198-T3 alloy after the further aging. Pre-deformation increased the number of dislocations in the matrix, which provided favorable position for nucleation of T 1 . The precipitation of θ ′ (Al 2 Cu) and δ ′ (Al 3 Li) were inhibited. Also, the formation and coarsening of precipitate-free zone (PFZ) were effectively avoided in this condition. Dislocation density in the 2198 Al-Li alloy matrix increased with the amount of pre-deformation, leading to an increase in micro-crack defects on the surface and inside alloy. As a result, decreased fatigue life and an increased crack growth rate of the alloy were observed. Overall, 2198 Al-Li alloy had the best fatigue life and damage tolerance enhancement after it underwent 3% pre-deformation and was aged at 155 °C for 15 h.