Near threshold fatigue crack growth in ultrafinegrained copper

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Arzaghi, M.^1 ; Fintová, S.^2 ; Sarrazin-Baudoux, C.^1 ; Kunz, L.^3 ; Petit, J.^1

PPRIME Institute UPR 3346 CNRS, ISAE-ENSMA, Université de Poitiers, France^1

Brno University of Technology, CEITEC BUT-Central European Institute of Technology, Technická 3058/10, 616 00 Brno, Czech Republic^2

Institute of Physics of Materials, AS CR, Zizkova 22, 61662 Brno, Czech Republic^3

关键词: Coarse-grained;    Effect of environments;    Effective stress intensity factor;    Field emission scanning electron microscopes;    Focused ion beam technique;    Near thresholds;    Orders of magnitude;    Ultrafine-grained copper;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012158/pdf
DOI  :  10.1088/1757-899X/63/1/012158

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The near threshold fatigue crack growth in ultrafine-grained (UFG) copper at room temperature was studied in comparison to conventional coarse-grained (CG) copper. The fatigue crack growth rates da/dN in UFG copper were enhanced at ΔK ≤ 7 MPa√m compared to the CG material. The crack closure shielding, as evaluated using the compliance variation technique, was shown to explain these differences. The effective stress intensity factor amplitude AKeff appears to be the same driving force in both materials. Tests performed in high vacuum on UFG copper demonstrate the existence of a huge effect of environment with growth rates higher of about two orders of magnitude in air compared to high vacuum. This environmental effect on the crack path and the related microstructure is discussed on the basis of fractography observations performed using scanning electron microscope and completed with field emission scanning electron microscope combined with the focused ion beam technique.