Method comparison for the determination of stretch zone parameters

21st Chemnitz Seminar on Materials Engineering – 21. Werkstofftechnisches Kolloquium

Hähnel, U.^1 ; Markus, M.^1 ; Hübner, P.^1

University of Applied Sciences, Faculty Engineering Sciences, Germany^1

关键词: Digital microscopes;    Fracture behaviour;    Fracture surfaces;    Mechanical characteristics;    Mechanical parameters;    Method comparison;    Stretch zone;    The scanning electron microscopes (SEM);   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/480/1/012025/pdf
DOI  :  10.1088/1757-899X/480/1/012025

来源: IOP

【 摘 要 】

The fracture behaviour of ductile failing materials is evaluated by parameters of yielding fracture mechanics. According to ISO 12135 the determination of fracture mechanical characteristic values involves, among other things, analysing the stretch zone width (SZW) in the scanning electron microscope (SEM). This procedure is very time-consuming and requires great experience in handling SEM images of fracture surfaces. An alternative method for determining the stretch zone parameters works with 3D elevation profiles of the fracture surface in the stretch zone area taken with a digital microscope. The fracture mechanical parameters determined using the above methods were finally compared. The Ji and δi values of scrap steels resulting from the digital determined SZW show a good agreement with analytically determined crack initiation values (Ji/BL , δi/BL ).