Browsing by Subject "Ductile fracture"

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Open Access
A model-based investigation of tool-chip friction during precision micro cutting of commercially pure titanium alloy
(Inderscience Publishers, 2022) Aksin, Alp; Karpat, Yiğit
Understanding interaction between the cutting tool edge radius and the work material is essential to identify the conditions leading to superior surface finish during the micromachining process. The interaction between friction angle and effective rake angle has been investigated based on a slip-line field-based machining model from the literature. Machining forces and cut chip thickness values were obtained from orthogonal cutting tests and employed in the process model. The proposed model also allows for calculating material properties such as shear flow stress and fracture toughness. The proposed model can successfully simulate machining forces during shearing-dominated machining conditions. The results showed the importance of flank and rake face friction in micro-scale machining.
Open Access
The role of intermetallic particles on mode I crack propagation mechanisms in metal plates
(Elsevier Ltd, 2021-08) Tekoğlu, C.; Çelik, Ş.; Duran, Hatice; Bair-Stegmaier, S.; Nielsen, K. L.
In metal plates, the crack propagation mechanism sets the amount of the plastic deformation before failure: a slanted or a cup–cone crack typically yields limited plate thinning within the fracture process zone, while large deformation precedes cup–cup crack propagation. The present work investigates the effect of intermetallic particles on the propagation mechanisms and the associated fracture surface morphologies when tearing Al 1050 plates under far-field mode I loading. Both single edge notched and double edge notched tension specimens, with thicknesses ranging from 0.5 to 5 mm, were tested. The chemical compositions of intermetallic particles were determined by performing energy dispersive X-ray measurements, and their morphological features were characterized by Scanning Electron Microscopy (SEM). Likewise, SEM images were taken to display the fracture surfaces, and the details of the surface morphology were visualized in three dimensions by using X-ray Tomography scanning. The experimental results indicate that an increase in the volume fraction, size, and aspect ratio of the intermetallic particles all promote slanted/cup–cone cracks, while a low amount of small, circular particles leads to cup–cup cracks. Furthermore, two-dimensional finite element simulations for mode I crack propagation support the experimental findings.