The mechanism of internal fatigue-crack initiation and early growth in a titanium alloy with lamellar and equiaxed microstructure
Language
en
Article de revue
This item was published in
Materials Science and Engineering: A. 2020-11, vol. 798, p. 1-14
Elsevier
English Abstract
Traditionally, equiaxed alpha grains rather than lamellar microstructure (LM) domains in titanium alloys are regarded as potential internal crack origins in high-cycle fatigue (HCF) and very-high-cycle fatigue (VHCF) ...Read more >
Traditionally, equiaxed alpha grains rather than lamellar microstructure (LM) domains in titanium alloys are regarded as potential internal crack origins in high-cycle fatigue (HCF) and very-high-cycle fatigue (VHCF) re-gimes. Here, we found that the fatigue crack is prone to initiate from a large LM domain in a titanium alloy with the composition of LM and equiaxed microstructure (EM) of fine alpha grains. Then, the mechanisms of internal crack initiation and early growth for the cases of HCF and VHCF under stress ratio R =-1, 0.1 and 0.5 were addressed and a mechanism chart was constructed to illustrate the internal cracking behavior, especially showing that the numerous cyclic pressing process dominates the related microstructure evolution with grain size refinement and nanograin formation underneath the fracture surfaces in the region of crack initiation and early growth.Read less <
English Keywords
Titanium alloy
Crack initiation
Facet
Very-high-cycle fatigue
Lamellar microstructure
Origin
Hal imported