Three-dimensional analysis of MMC microstructure and deformation by μCT and FE simulations

Crostack, H.‐A.; Nellesen, J.; Fischer, G.; Weber, Ulrich; Schmauder, Siegfried; Beckmann, Felix

doi:10.1117/12.795206

Cited by 8 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, digital image correlation (DIC) was employed (i.e., incremental correlation: see, e.g., Tong et al, 2005;Zavattieri et al, 2009a) for unpolished specimens. This method has been applied in previous works to SEM and IR images (Crostack et al, 2001;Feng et al, 2012;Tillmann et al, 2013) as well as to tomograms (Crostack et al, 2008;Fischer et al, 2013). Both methods are used to obtain IRR intensity-based images of the PLC band as a function of time during the tests.…”

Section: Experimental Set-up and Testingmentioning

confidence: 95%

Thermomechanical characterization of Portevin–Le Châtelier bands in AlMg3 (AA5754) and modeling based on a modified Estrin–McCormick approach

Klusemann

Fischer

Böhlke

et al. 2015

International Journal of Plasticity

Self Cite

View full text Add to dashboard Cite

Section: Experimental Set-up and Testingmentioning

confidence: 95%

Thermomechanical characterization of Portevin–Le Châtelier bands in AlMg3 (AA5754) and modeling based on a modified Estrin–McCormick approach

Klusemann

Fischer

Böhlke

et al. 2015

International Journal of Plasticity

Self Cite

View full text Add to dashboard Cite

“…Table 1 lists the composition and the particle mean size of the above mentioned two types of samples, which the manufacturer provides. Type-I in Table 1 behaved ductile, more information about which can be found in [49,50]. Type-II in Table 1 showed quasi-brittle behavior.…”

Section: Materials and Experimentsmentioning

confidence: 93%

“…As a comparison, selected deformation characteristics of type-I will be also mentioned here. Table 2 shows material properties, Young's modulus, Poisson's ratio, and thermal expansion coefficient, for the pure Co, the pure WC, and the diamond [49,50]. In Kim et al [25], the measured Young's moduli and the Poisson's ratios are 714 GPa, 0.19 for WC and 211 GPa and 0.31 for Co, accordingly.…”

Section: Materials and Experimentsmentioning

confidence: 99%

“…Comparatively, significantly fewer works reported material properties for composites with WC <50 vol.%. Crostack et al [49,50] measured the strain field and the crack development near diamond's sharp corners on the meso scale for Co/WC/diamond composites (WC <50 vol.%) using µCT. The global strain reached about 10-11% under tension, i.e., ductile behavior.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental Investigations of Micro-Meso Damage Evolution for a Co/WC-Type Tool Material with Application of Digital Image Correlation and Machine Learning

Schneider

Zielke

et al. 2021

Materials

Self Cite

View full text Add to dashboard Cite

Commercial Co/WC/diamond composites are hard metals and very useful as a kind of tool material, for which both ductile and quasi-brittle behaviors are possible. This work experimentally investigates their damage evolution dependence on microstructural features. The current study investigates a different type of Co/WC-type tool material which contains 90vol.% Co instead of the usual < 50vol.%. The studied composites showed quasi-brittle behavior. An in-house-designed testing machine realizes the in-situ micro-computed tomography (CT) under loading. This advanced equipment can record local damage in 3D during the loading. The digital image correlation technique delivers local displacement/strain maps in 2D and 3D based on tomographic images. As shown by nanoindentation tests, matrix regions near diamond particles do not possess higher hardness values than other regions. Since local positions with high stress are often coincident with those with high strain, diamonds, which aim to achieve composites with high hardnesses, contribute to the strength less than the WC phase. Samples that illustrated quasi-brittle behavior possess about 100–130 MPa higher tensile strengths than those with ductile behavior. Voids and their connections (forming mini/small cracks) dominant the detected damages, which means void initiation, growth, and coalescence should be the damage mechanisms. The void appears in the form of debonding. Still, it is uncovered that debonding between Co-diamonds plays a major role in provoking fatal fractures for composites with quasi-brittle behavior. An optimized microstructure should avoid diamond clusters and their local volume concentrations. To improve the time efficiency and the object-identification accuracy in CT image segmentation, machine learning (ML), U-Net in the convolutional neural network (deep learning), is applied. This method takes only about 40 min to segment more than 700 images, i.e., a great improvement of the time efficiency compared to the manual work and the accuracy maintained. The results mentioned above demonstrate knowledge about the strengthening and damage mechanisms for Co/WC/diamond composites with > 50vol.% Co. The material properties for such tool materials (> 50vol.% Co) is rarely published until now. Efforts made in the ML part contribute to the realization of autonomous processing procedures in big-data-driven science applied in materials science.

show abstract

“…Our sample material, much less studied as compared to those with WC as the matrix, is also a kind of tool materials, e.g., for cutting and grinding. Such materials can show both ductile and quasi-brittle behaviors [39,40]. Figure 8a presents a real 2D microstructure cut-out of a Co/WC/diamond composite with 9.06 vol.% diamond, where the volume ratio of Co:WC:diamond is 90:5:5 for the commercial sample.…”

Section: Further Applicationsmentioning

confidence: 99%

A Numerical Method to Improve the Representativeness of Real Microstructure Cut-Outs Applied in Finite Element Simulations

et al. 2021

Self Cite

View full text Add to dashboard Cite

To improve the representativeness of a real microstructural cut-out for modeling purposes, a numerical method named as “boundary pixel color alteration (BPCA)” is presented to modify measured 2D microstructure cut-outs. Its physical background is related to the phase growth. For the application, the precondition is that the representativeness of the microstructure is already satisfied to a certain extent. This method resolves the problem that the phase composition of a small cut-out can have a large discrepancy to the real one. The main idea is to change the pixel color among neighboring pixels belonging to different phases. Our process simultaneously maintains most of the characteristics of the original morphology and is applicable for nearly all kinds of multi-phase or polycrystalline metallic alloys, as well. From our axisymmetric finite element (FE) simulations (ABAQUS ) applied with 2D real microstructures, it shows that the volume ratios of microstructural phases, as a function of the structure position to the symmetric axis, converge to phase area ratios in the 2D cut-out, even though the axisymmetric element volume is position dependent. A mathematical proof provides the reason for the aforementioned convergence. As examples to achieve real compositions and to numerically prove the aforementioned convergence, four different materials including multiphase polycrystals are implemented. An improvement of the predicted FE result is presented for the application of a modified microstructure (with a higher representativeness) compared to the original one.

show abstract

Three-dimensional analysis of MMC microstructure and deformation by μCT and FE simulations

Cited by 8 publications

References 0 publications

Thermomechanical characterization of Portevin–Le Châtelier bands in AlMg3 (AA5754) and modeling based on a modified Estrin–McCormick approach

Thermomechanical characterization of Portevin–Le Châtelier bands in AlMg3 (AA5754) and modeling based on a modified Estrin–McCormick approach

Experimental Investigations of Micro-Meso Damage Evolution for a Co/WC-Type Tool Material with Application of Digital Image Correlation and Machine Learning

A Numerical Method to Improve the Representativeness of Real Microstructure Cut-Outs Applied in Finite Element Simulations

Contact Info

Product

Resources

About