Number of the records: 1
Fatigue crack propagation in UFG Ti grade 4 processed by severe plastic deformation
- 1.
SYSNO ASEP 0471662 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Fatigue crack propagation in UFG Ti grade 4 processed by severe plastic deformation Author(s) Fintová, Stanislava (UFM-A) ORCID
Arzaghi, M. (FR)
Kuběna, Ivo (UFM-A) RID, ORCID
Kunz, Ludvík (UFM-A) RID, ORCID
Sarrazin-Baudoux, C. (FR)Number of authors 5 Source Title International Journal of Fatigue. - : Elsevier - ISSN 0142-1123
Roč. 98, MAY (2017), s. 187-194Number of pages 8 s. Language eng - English Country GB - United Kingdom Keywords Titanium ; Fatigue ; Crack growth ; Crack closure ; Equal channel angular processing Subject RIV JL - Materials Fatigue, Friction Mechanics OECD category Audio engineering, reliability analysis R&D Projects LQ1601 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) LM2015069 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UFM-A - RVO:68081723 UT WOS 000398008100018 EID SCOPUS 85011407783 DOI 10.1016/j.ijfatigue.2017.01.028 Annotation Fatigue crack growth was investigated in commercially pure Ti grade 4 processed by severe plastic deformation. The ultrafine-grained structure was prepared by means of equal channel angular pressing technique followed by cold drawing. The growth of fatigue cracks was investigated also in the as-received coarse-grained state of material for comparison.
The fatigue crack growth rate in the ultrafine-grained material was found to be higher and the threshold stress intensity range delta Kth for crack growth lower than in the coarse-grained Ti, 2.5 and 4.7 MPa m1/2, respectively. A combination of transcrystaline and intercrystaline crack growth was typical for all crack growth rates in the coarse-grained material. Contrary to the combined fracture mechanism in coarse-grained Ti only transcrystalline crack growth was a characteristic feature of crack propagation in the ultrafine-grained material.
It has been found that the experimentally and theoretically determined values of closure are in reasonable agreement. Crack closure calculated according to the Newman model taking into account only plasticity induced closure was in the range from 67% to 69% of Kmax for as-received and 70% for UFG state of material. Crack closure determined experimentally was 67% of Kmax for as-received and 67% for UFG CP Ti grade 4.
Investigation of fracture surfaces did not bring any evident signs of the effects of fracture surface morphology resulting in roughness induced closure or oxide induced closure under testing conditions used. This indicates that plasticity induced closure seems to be a dominant closure mechanism in both states of the investigated Ti grade 4.Workplace Institute of Physics of Materials Contact Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485 Year of Publishing 2018
Number of the records: 1